Let?s make this a fiberglass information thread!

[jcsftwre]

Let?s try to accumulate fiberglassing information in this thread but not intended for asking questions, please. This way it can be a one stop shop to find information on the subject.
​

If we can do this without having questions here it will be just facts and not have the information get lost in questions. Fiberglass questions will be happily answered in this forum when asked.​

This is not mandatory but just a very kind request.​

Some information given shale be opinions or personal advice. Remember this, they are just opinions and advice from individuals. Please respect one & other.​

 

[jcsftwre]

How much resin do I need? & Suggested Reading

How much resin do I need? & Suggested Reading

More Information: http://www.iboats.com/Fiberglass_Boat_Repair_Manual/dm/*******.186416504--list_time.1227973818--**********.460012336--view_id.12698

Fiberglass Information, and How much resin do I need?
Please remember several things: These are estimates not hard and fast rules. If you are laminating over wood, the raw wood will soak up some resin, which is good, but you will use more resin on the first layer. Thin resin goes farther than thick resin.
Chopped strand mat:
The general rule for chopped stand mat is 1.5 to two times the weight in resin to the weight of mat.
For 1.5 ounce chopped strand mat you will need 3 to 4 ounces per SQUARE FOOT.
For 2.0 ounce chopped strand mat you will need 4 to 5 ounces per SQUARE FOOT.
There are about 150 ounces or resin by weight per gallon. Example: 10 square yards of chopped strand mat is 90 square feet. 90 x 4 = 360 oz. 360 oz of mat divided by 150 oz per gallon gives you 2.4 gallons.
Material to approximate gallons of resin used.
1.5 OZ MAT = 1 gallon covers 4.2 square yds
2.0 OZ MAT = 1 gallon covers 3.4 square yds
Here is a helpful table for cloth:
There are about 150 ounces per gallon by weight
1.5 ounce cloth (cloth not chopped mat)?.1 gallon wets out 40 square yards
2.5 ounce cloth?.1 gallon wets out 25 square yards
4 ounce cloth??1 gallon wets out 15 square yards
6 ounce cloth??1 gallon wets out 10 square yards
10 ounce cloth?..1 gallon wets out 6.5 square yards
18 ounce woven roving ?1 gallon wets out 4.5 square yards
24 ounce woven roving ?1 gallon wets out 3.5 square yards.
Biaxial mat 1708.????.. 1 gallon wets out 4 square yards

 

[jcsftwre]

Types of reinforcement cloth

Types of reinforcement cloth

Woven cloth

Fiberglass cloth is woven on textile weaving machinery. It can be woven several different ways, plain weave, long shaft satin weave, and unidirectional weave. There are also other more complicated weaves, such as twill weave,
Fiberglass cloth is measured by ounces per yard in the USA, and grams per square yard in Europe. Cloth sold in the USA can vary from one half ounce per square yard, up to over 50 ounces per square yard. The most commonly used weights for most projects are four, six, and ten ounces per square yard.
Most cloths that you will find yourself using are plain weave. Plain weave cloth usually has the same number of strands running its length and width (warp and weft). Plain weave produces a stiffer end product than most other weaves, and because it has the same number of strands running in each direction it is easier to keep the laminate strength balanced.
Plain weave cloth is ideal for large and simples molds, and flat, or nearly flat surfaces.
Woven cloth gives the most strength, but is the least thick. Cloth requires the least amount of resin, this makes the cloth very strong, but it lacks stiffness. Also, it does not give good waterproof-ness because of the small amount of resin. It is the resin, not the cloth that gives you the waterproof-ness. To solve this problem, cloth is usually layered with chopped strand mat.
Fiberglass cloth

CHOPPED STRAND MAT

More Information: http://www.iboats.com/MAS_Fiberglass_Mat/dm/*******.186416504--list_time.1227972978--**********.460012336--view_id.342217

Chopped strand mat is made by laying down chopped strands of glass fibers in a random pattern on a flat surface. Each stand is about two inches long. A bonding agent (usually a powder) is used to hold the strands together. The result is a mat of even thickness , made up of fibers going in every possible direction. This will give you strength in every possible direction.
CSM as we will call it, is sold in ounces per square foot. All other reinforcements are sold in ounces per square yard. It can be purchased in weights ranging from ? ounces per square foot, up to 4 ounces per square foot. In the USA the two most used weights are 1.5 ounce, and 2.0 ounce per square foot.
The CSM that you find in stores, in plastic packages is 1.5 ounces per square yard.
CSM usually comes in widths from 38 to 50 inches. In can be purchased by the yard or in large rolls.
CSM is the least expensive of all reinforcements, and it is very versatile. CSM soaks up more resin than any other reinforcement. The advantage of this is that is gives more waterproof-ness than any other type of reinforcement. CSM produces the stiffest laminate, and because the strands are in a random pattern, it gives strength in every direction.
For repairs jobs , CSM is the easiest material to use. It is easy to wet out, or saturate with resin. In its dry state it is fairly stiff and will not easily go into tight curves, but when saturated with resin, the binder holding the individual strand together breaks down, and this allows the mat to be shaped into any configuration.
When using mat on curved surfaces, 1.5 ounce per square foot is recommended. 2.0 ounce is better suited for flat surfaces, and for buildup, because it is stiff.
It takes about 20 layers of 1.5 ounce CSM to make a laminate 1 inch thick. In most repairs , two layers of CSM will be sufficient, but you can make it as thick as you wish to get the desired strength.

Woven Roving

More Information: http://www.iboats.com/MAS_Woven_Roving/dm/*******.186416504--list_time.1227973029--**********.460012336--view_id.341118

Fiberglass woven roving is different from fiberglass cloth. Fiberglass cloth is made from glass fiber thread that is twisted like yarn, woven roving is made from continuous strands of glass fibers that are grouped together. Woven roving is a thick cloth like reinforcing material. In the 18 and 24 ounce weights, it is as thick as a blanket. The two most common weights for woven roving, are 18, and 24 ounces per square yard.
Woven roving is mostly used for buildup when thickness is needed. It is alternated with layers of chopped strand mat to fill in the heavy weave pattern of the woven roving.
The combination gives good thickness and strength. On a weight basis, woven roving is cheaper than cloth, and more expensive than chopped strand mat.. The advantage of using woven roving, is that is gives a quicker buildup of thickness , compared to using cloth. Because of the heavy thick weave, you are not going to get the nice smooth finish of cloth when you use woven roving. , that is why it is generally used for buildup, after you use cloth for your first layer , to get the smooth finish. Like cloth. Woven roving uses less resin then chopped strand mat. That is why in situations that require waterproof ness, chopped strand mat is used in combination with woven roving.

BIAXIAL MAT

More Information: http://www.iboats.com/West_System_737_738_Biaxial_Fabric/dm/*******.186416504--list_time.1227973615--**********.460012336--view_id.13264

There is a product available called ?combination mat? or Biaxial mat . It is a ?combination? of woven roving , and chopped strand mat. They are stitched together. It is sold in various weights. It is also called stitch bonded mat. This is used to save time when very heavy buildup is needed. It is flat instead of woven and has a better appearance than woven roving. It also has the advantage of saving on resin because you are doing two steps at one time ( roving and mat). In most projects resin will be your highest expense, so the higher expense of Biaxial mat may be worth it. Many of our clients have switched to it.

CARBON FIBER

Carbon fiber looks much like woven roving, except that it is usually black in color. Each strand of carbon fiber is made up of 3,000 or more individual strands of carbon fiber thread. The resulting product is so many times stronger than E, or S glass . Carbon fiber is used when great strength is needed, but light weight is desired. One layer of Carbon Fiber is equal to many layers of Fiberglass cloth. It is used and applied in the same manner as any other reinforcement. The big drawback is the price. It is very expensive. It is used in race cars, speed boats, wind turbines, airplanes, any place where you need superior strength, and light weight.

 

[jcsftwre]

Resins

Resins

Note: When you apply resin to your fiberglass, the fiberglass is properly saturated when it becomes completely clear.

Polyester resin

More Information: http://www.iboats.com/Marine_Store/dm/*******.186416504--current_category.--keywords.Polyester%20resin%20--search_in_category.f--**********.576691099--submit.x.30--submit.y.5

Polyester resin is a thermosetting plastic. Thermosetting means that it is set or cured by heat, which can either be applied chemically from the inside, or from the outside. An accelerator or catalyst, commonly known as the curing agent is added to create the internal heat. Polyester resin is used at room temperature. When the curing agent is evenly mixed in, this causes an internal heat, which in turn causes the resin to cure, or harden. You can control the working time of the resin by the amount of catalyst you use. However, if you use too little, it will not cure at all. Most of the time you will be buying the resin in quarts, or gallons. It will come with a clear liquid (usually MEKP) in a small plastic container . The resin will come with a chart that will tell you how much of the catalyst to use to get the desired working time .
Working time can range from 5 minutes to one hour. Caution: all resins have a shelf life. Usually about one year FOR POLYESTER, AND THEE YEARS FOR EPOXY. After that they are no good. Fiberglass reinforcement can last for years and years in dry storage, and will still be good, but old resin is useless.
The Polyester resin you will most commonly buy is called a ?general purpose resin.? this means that it is good to use for most any job that you re going to do. Polyester resin is used when you are starting from scratch, epoxy resin is used when you are. Bonding. Epoxy is used when you are bonding new fiberglass to old fiberglass, or bonding fiberglass to metal or plastic, etc. Epoxy is also used when you are going to need flexibility, polyester is rigid and not flexible.

LAMINATING AND FINISHING RESINS

Many types of polyester resin have been developed for specific purposes. The two basic types are laminating, and finishing (also called surface) resin.
The laminating, or layup resin is air inhibited, which means that in the presence of air it will not cure fully. This will leave the surface tacky. This condition is actually desirable when additional layers of fiberglass are to be added to the laminate, as there is no waxy surface to prevent the next layer to adhere properly.

Finishing, or surface resin, is non-air inhibited, which means that it will fully cure in the presence of air. This is desirable for the final layer of a laminate. Non air inhibited resin has a wax or similar ingredient added. When the catalyst is added, the wax rises to the surface, sealing off the air, and allowing a complete cure. The surface then can be sanded.
Laminating, or layup polyester resin can be made tack free by adding a special wax to the resin , prior to application. Another method of achieving a cure when laminating or layup resin is used is to seal the surface from the air. This can be achieved with a layer of cellophane or plastic. All possible areas where air could come in must be taped off.

When finishing surface resin is used, it cures with a waxy surface. If you intend to add another layer to this, the wax must be removed. You can either sand it off, or wipe it off with acetone .
The general purpose resin we spoke of earlier gets around all of these problems. Some pros look down on general purpose resin, but most people who use it find that it is satisfactory for most types of fiberglass repair work, and small jobs.
For large jobs, study up on the laminating and finishing resins, rather than a general purpose resin.

EPOXY RESIN

More Information: http://www.iboats.com/Boat_Epoxy_Resin/dm/*******.186416504--**********.576691099--view_id.217327

Epoxy resin is usually twice as expensive as poly. Instead of resin and hardener, epoxy comes in a two part system. You cannot control the working time of epoxy resin, so start with small quantities until you get your experience. You use epoxy resin just like poly. Saturate the cloth until it becomes clear, work out the bubbles, and wait for it to set..
APPLYING RESIN OF EITHER KIND

First read and follow mixing instruction on the can. Wear all proper protective clothing, have proper ventilation, and use a respirator. The best and easiest way to apply resin is to mix it, and then pour it directly onto the surface you are working. If you are fiberglassing over plywood, you must first apply resin to the wood to let it soak in. With polyester resin, you can roll on a primer coat, let it dry, and then continue, with epoxy , you have more working time, so apply epoxy resin to the bare wood then lay down your cloth or mat. Lay the dry cloth down on the surface, pour the resin on, and then spread it out with plastic disposable putty knives you can get at your local home store. Spread the resin around. When the material becomes clear, it is properly saturated. Move the resin from the clear areas to the dry areas. You will need a laminate roller, or bubble buster roller to get the air bubbles that are trapped under the resin. When it is not possible to pour the resin on, use disposable paint rollers. For mixing you can buy containers that are marked in ounces and quarts at your local home store.

GEL COAT

More Information: http://www.iboats.com/Marine_GelCoat_Repair/dm/*******.186416504--**********.460012336--view_id.246645

Gel coat is a type of polyester resin. Its main use it to form the protective color coat on the outer surface of a fiberglass mold. If you have ever seen a fiberglass boat, you have seen the shiny gel coat surface.
Gel coat comes in clear, or colored, or you can add your own pigment. Gel coat is applied over the mold release agent that is first applied to the mold. Then the various layers of reinforcement are added. Gel coat touch up kits are available at most boating stores, just follow directions.

MOLD RELEASE AGENTS

Whatever type of mold you are using, wood, metal, plastic etc. , you must first apply a mold release agent to the entire surface of the mold. If you do not, you will not be able to remove the finished product from the mold.
( you do not use mold release agent when you are applying fiberglass to a surface that you want it to stick to forever, like a surfboard, or the deck of your boat) Most mold release agents have to be applied in several layers, but there is a one part mold release agent on the market. See what your local boat supply store has , or look at a boat supply internet store, which is more likely to have the latest thing. All of the release agents come with full directions. After applying the release agent, be careful when applying your first layer of reinforcement. If you scratch of the mold release agent, the mold will stick in that area.

 

[jcsftwre]

Tools Equipment And Supplies

Tools Equipment And Supplies

More Information: http://www.iboats.com/Epoxy_Fiberglass_Composite_Tools/dm/*******.186416504--**********.460012336--view_id.366223

Mixing containers are used for mixing your resins, for holding solvent agents for cleaning brushes and tools, etc. Disposable mixing containers are sold very cheaply at boating supply stores. Do not use paper containers , because they usually have a wax coating that will contaminate your mix. Disposable plastic containers are most desirable. Most of them come with ounces and cups measured on the side. Always buy more than you need. You will want to mix your resins in amounts you can use before they cure up. You can pour the mixed resin directly onto your project, and then work it around with a plastic squeegee.

MIXING STICKS

Here is another no- brainier . Wooden mixing sticks are either very cheap or free at most paint stores. Get more than you think you will need, and dispose of them after each use.
PAINT BRUSHES
Paint brushes can be used to apply resin to small areas, or too hard to reach areas. We recommend cheap throw away brushes. You can clean up a brush with acetone, but it will be more time and trouble than it is worth.

SQUEEGEES

Here is another cheapee that you must buy more of than you think you will need. Plastic squeegees cost about 69 cents, but they are worth their weight in gold when it comes to spreading resin. On a flat mold, you can pour on some resin, spread it with the squeegee, then lie on your cloth, pour on more resin, and spread it evenly with the squeegee. Each time a squeegee gets fouled up, set it aside and start a new one. Sometimes when the resin dries, you can bend the squeegee, and the resin will break off evenly and you can use it again. Get a few different size Squeegees for different size areas.

SCISSORS

A good pair of cloth cutting scissors will cut any reinforcement that you are using. Eclectic scissors are available for big jobs.

MASKING TAPE

Keep a good supply of masking tape handy to mask of areas you don?t want to ruin, and to tape off plastic barriers if you choose to use the,

RAGS

Rags are a man?s best friend when working with resins. Buy a bag of cheap disposable rags. Always use white rags only because resin will dissolve the dyes in colored rags, and make a mess!

PUTTY KNIVES

Flexible putty knives come in various sizes. They are useful for applying putty and fillers.

CELLOPHANE

As we discussed before, there are times when you have to seal off a project from air. Cellophane is good for small areas, plastic is better for large areas.

UTILITY KNIVES

Keep a good supply of blades on hand. You can cut cloth on a hard surface with a utility knife, and you will find yourself needing the knife for many other uses.

SAND PAPER

There are many different kinds of sand paper, and all kinds can be used on fiberglass. Sanding is usually done by starting with the heavy grits, and working down to the finer grits. 80 grit is extremely coarse, 150 is medium, and 600 grit is for very fine sanding.

FIBERGLASS RUBBING AND POLISHING COMPOUND

This is used for making gel coat repairs, and for the maintenance of gel coats. Read and follow directions.

LAMINATING LAY UP ROLLERS.(bubble buster rollers)

These are used to remove air bubbles from your project as you lay on the resin. After laying on the fiberglass , and using the Squeegee to evenly apply the resin, use the roller to work out any air bubbles. Work from the center, and push the bubbles out to the sides, and then away. These rollers are available wherever resin is sold.

PAINT ROLLERS AND TRAYS

More Information: http://www.iboats.com/Boat_Painting_Supplies/dm/*******.186416504--**********.576691099--view_id.217340

Paint rollers are very useful for applying resin to large areas. As always, buy cheap throw away roller covers, and plastic disposable tray liners. Paint rollers can also be used for another neat trick that will save sanding time. While the resin is still wet, lay clear plastic film over the wet surface. Gently use the roller to smooth the plastic over the surface. Then slowly remove it before the resin dries. This will save sanding time in the end.

CUTTING WHEEL

More Information: http://www.iboats.com/Sanding_Supplies/dm/*******.186416504--**********.219763963--view_id.478590

Every home store sells a cutting wheel attachment for your drill. You will find this very useful in cutting away the parts of the finished product you do not need. Wear your respirator.

PROTECTIVE CLOTHING

We cannot stress enough the importance of protecting your eyes, skin, and lungs from the fiberglass, and the resins. Always cover your skin completely, wear gloves, respirator, and eye protection.

Fiberglassing A Plywood Deck or Roof
More and more it is becoming popular to fiberglass plywood decks or roofs.
First you must decide on materials. You will be using Chopped strand mat for your fiberglass and polyester resin for your resin.
1.5 ounce chopped strand mat is usually adequate for most applications, it will give you a hard waterproof finish, however if you want to go that extra mile, or if the area is going to be subjected to high traffic or heavy weight usage we would recommend using 2 ounce chopped strand mat.

Step one is to calculate how much mat you will need. Chopped strand mat comes in a 50 inch width, so let?s call it four feet wide. Therefore each linear yard is 12 square feet. For our sample deck, we are going to use the measurements of 12 x25. A 12 x 25 foot deck will need 300 square feet of material. 300 square feet divided by 12 = 25 linear yards of mat . You take the square footage of the deck (300) and divide it by 12 to get the number of linear yards you will need for your project.

Next, how much resin. We will do the calculations for 1.5 ounce chopped strand mat, and 2.0 chopped strand mat. The rule of thumb is for each square foot of 1.5 you will need 3 ounces of resin, but because you are going over raw plywood ( never pressure treated! Note: some people agree and some don?t. It is up to you!) , you must account for the amount the wood will soak up. So our rule of thumb is going to be 4 ounces per square foot for 1.5 ounce, and 5 ounces per square foot for 2.0 ounce.

This is how you do the calculations:
You take the number of square feet of your deck times the number of ounces of resin. For our 300 square foot deck it goes like this.
For 1.5 ounce mat
300 x 4 = 1200 ounces
Then you divide by the number of ounces by WEIGHT in a gallon. The number of ounces by weight in a gallon is 150. So 1200 ounces divided by 150 gives us 8 gallons.
For 2.0 ounce mat
300 x 5 = 1500 ounces
1500 oz Divided by 150 = 10 gallons of resin.
Just take the number of square feet of your deck times it by either 4 or 5 then divide by 150 to get the number of gallons of resin you will need.
Now what else will you need before getting started.?

Get the chopped strand mat, and resin, you will also need a couple of laminate rollers. Laminate rollers are not for spreading the resin, they are for pressing the resin down, and popping out the air bubbles. They look like 40 little pizza cutters linked together on a roller.

 

[jcsftwre]

Here are a list of things you will need to get

Here are a list of things you will need to get

Acetone for clean up

ore Information: http://www.iboats.com/Evercoat_Acetone/dm/*******.186416504--list_time.1227978835--**********.576691099--view_id.38718

Rubber gloves

More Information: http://www.iboats.com/West_System_832_Disposable_Gloves/dm/*******.186416504--list_time.1227979537--**********.576691099--view_id.259785

Eye protection

ore Information: http://www.iboats.com/3m_Splash_Proof_Safety_Goggles/dm/*******.186416504--list_time.1227979421--**********.576691099--view_id.21507

Respirator

More Information: http://www.iboats.com/Respirators/dm/*******.186416504--**********.576691099--view_id.246658

Protective coveralls

More Information: http://www.iboats.com/Lakeland_Industries_Protective_Coverall/dm/*******.186416504--list_time.1227979639--**********.576691099--view_id.20893

1.5 gallon plastic mixing buckets, marked of in quarts
Paint stirs
Plastic squeegees, such as disposable mud knives 8??, and some smaller disposable putty knives. These will be used to spread the resin.
Mini Disposable paint rollers 4 inch

 

[jcsftwre]

Getting started

Getting started

First, the plywood must be bone dry, any moisture at all will stop the resin from soaking in, and you will have wasted you time and money. Sweep or blow of any dust from the deck.

Now, pre cut your pieces of mat to fit your deck. Once you get going you will not want to stop to do this, so do it ahead of time.

Lay down the first section of mat.

Now it must be between 65 and 90 degrees F when you are doing the work. If it is too cold the resin will never set, if it is too hot it will set to quickly.

Never work in the direct sunlight. For your First batch, mix a small amount of resin, one or two quarts. (You must mix the resin with a stick for two minutes, or with a power drill attachment for one minute, a complete mixing is very important.)

This first batch will give you a feel for the working time of the resin. You will usually have ten minutes per batch, so have all your ducks in a row before you add the hardener to the resin.

Do not add the wax to the resin if you plan to paint or gel coat the deck. We recommend a marine grade topcoat gel coat, or a very high quality (Sherwin Williams) porch and deck paint. You can also use Marine No- Skid paint.

If you are not going to paint, but are going to carpet, or cover with something else, add the wax as recommended in the directions that come with the resin. Keep in mind that when you overlap the sections of mat, you will have to sand off the wax and wipe it down with acetone so that the overlap layers will bond.

Now lay the mat down like a piece of carpet. Take the resin you have mixed, and pour it directly onto the mat. Gently spread the resin like butter on bread with your hard plastic spreader. . You do not want to move the strands of mat around, just the resin so be gentle . When an area is properly saturated with resin, it will turn from white to clear. Keep moving the resin from the wet areas to the dry areas.

This first batch will give you an idea of your working time, and how much resin you will need to mix each time.

Note: Resin builds up heat when it is in the mixing bucket. The more resin, the more heat. The more heat the shorter the working time. So , mix the resin, and get it out of the bucket ASAP! , or you will end up with a hot bucket of hard resin.

Also, Polyester resin is nasty stuff, you must wear all proper safety equipment, you do not want to get it on your skin or in your eyes, or you will end up with an injury. The fumes are also quite strong, so we recommend a proper respirator.

For each section overlap the mat at least one or two inches to ensure a waterproof deck. Keep laying out the mat, and spreading the resin until the entire deck is finished.

Flashings and overhangs;

If you want to run the mat 4 to 6 inches up the wall to get a waterproof seal , just fold the mat and rest it against the wall, use a disposable mini roller to roll the resin onto it, and press it down with the laminate roller.

The same goes if you want to do a lip around the deck, let the mat hang over the edge , bend it down, roll resin on it with the mini roller, and then press it down with the laminate roller.

After 24 to 48 hours, apply your deck paint or gel coat. Now you are finished, and if you did it right, it can last anywhere from 15 to 25 years.

Some information was obtained from FiberglassSite.com

 

[TK]

Re: Let?s make this a fiberglass information thread!

A good cheap cleaner when using epoxy resin....is plain old vinegar.

I use it to clean the chip brushes when I know I am doing another lay up in a day or two.

I also use vinegar to wash my lay up table after a lay up. I then follow with the acetone. It does a good job in saving dollars and smells much better.

It does not replace any of the above cleaners, however for spot cleaning and knowing you can wash your hands in it makes it a good thing to have around.

 

[jcsftwre]

Polyester compared to Epoxy resin.

Polyester compared to Epoxy resin.

Polyester compared to Epoxy resin.​

The most common cause for the line of thought that polyester doesn't bond to anything, is people doing a repair with little or no prep work, sometimes not even cleaning off the old dirt and gunk, then using cloth as the first layer. This type of repair will fail almost immediately and then the resin is blamed. For the best results use a grinder with 36 grit or coarser paper and keep the surface clean.

Yes, once the resin has cured you get less of a chemical bond and more of a mechanical bond, but there are still reactive sites in the old layup (resin) to bond with. The mechanical bond, while not quite as strong, is not weak and will take a great deal of abuse. You test the bond in the lab by pulling it apart, if it's been prepped well and the bond is good, glass fibers will be torn from each surface, which is common. Sometimes it doesn't separate along the new bond, it may be deeper into the old section or new one, and it may also be a combination of the two. If you did a poor job of prep or if the surface was contaminated for some reason, then the bond may (will) be poor and it may pull apart easily with little or no fiber sticking to either surface.

Mat & Roving cloth.​

Mat is used to build bulk and sort of help with the bond. If you use cloth or roving as the first layer, there is a resin rich layer between the glass and substrate, this resin rich layer is weak, just like the casting oops! made. Add glass fiber to it and it becomes strong, this is the roll of the mat, and fibers in the mat are random and will fill the area that cloth and roving won't. Now when stressed there is glass near the surface of the substrate, not just resin, so it will not fail like a cloth only layup will. The bond is actually the same as far as the resin is concerned; it's just that the resin isn't failing near the bond line now.

Some examples of contrition and what results to expect.​

Epoxy does bond better, the problem is, you still have polyester under it, and so if you exceed the stress level the polyester substrate can handle, the epoxy layup will still pull right off, only with some of the polyester still stuck to it. It's almost like the polyester to polyester test, except all of the failure is in the polyester substrate this time. Epoxy is much stronger, so this resin rich area at the bond line is less likely to fail when only cloth is used.

As far as doing repairs or rebuilds being done with epoxy compared to polyester, it won?t make a big difference in the finished product, these boats were made with polyester and normally the polyester didn?t fail it was the wood that rotted away. Wood rots from getting wet; it makes no difference which resin is used.

Don?t try to glue things together with polyester, it?s a poor glue and is somewhat brittle, epoxy ?is? a glue and works great. Don?t expect polyester to seal wood when used without glass, just coating the surface of wood with it will only hold up for a short period time, it will soon begin to crack and peel letting the wood get wet. Epoxy works better, a thin layer of glass (cloth) should be used for much longer lasting results though.

When glassing over wood.​

When glassing over wood with either type of resin always pre-coat the wood with resin and at least let it start to get hard before going any further. The wood may (will) suck up a great deal of resin which can pull resin out of the glass leaving dry areas which will be weak if you don?t.

Mat has the lowest strength of the typical types of glass on the market, it's not weak and may add strength and stiffness (don't confuse stiffness with strength), but other types of glass do a better job at adding strength for the same weight. Cloth works well for some things, but I rarely use it and most boat builders don't use it either, as the cost is high for the strength it adds. Roving is strong and is less costly than most other types of fabric, plus it's very easy to work with, so it gets used a great deal. Biaxial type products are very strong and add the least amount of weight for the strength and cost more, much of the time they come with a thin layer of mat stitched to them for better bonding and to help hold the resin in place.

Types of glass cloth.​

There are also two types of glass E and S, E is the most common and is what you will find most of the time. S is stronger and costs more, to buy it you normally need to special order it. When it comes to other high end types of fibers like carbon or Kevlar, use epoxy, they don't work well with polyesters.

Information on Polyester resin.​

Not all polyester resins are of the same quality and neither are epoxies and it can be very difficult to know what you?re buying. I'm not an epoxy guy, so I won't give information on it because it may not be accurate.

Polyester boats normally have a skin layer on the hull of a better grade of resin, it may be a straight VE, a VE-DCPD blend, or a straight ISO. This is a thin layer near the gel coat for better water resistance, this layer is commonly chopped, but it may be hand laid with mat. The rest of the hull and deck are normally made with an ORTHO-DCPD blend, it's not as strong or water resistant as VE or ISO, but costs much less.

Store bought resins, commercial resins. What works well.​

What you buy in the store is normally a straight ORTHO, because DCPD's and the blends with it added, have a shorter shelf life and they need a long shelf life for the retail market. You can get ISO and VE resin, but you normally need to go to a fiberglass supply store and ask for them, they will cost more. The VE will be stronger, more water resistant and bond better than ISO, which in turn is better than ORTHO, that leaves DCPD's at the bottom, but DCPD?s do offer very good surface profile because they shrink less than the other types. Straight DCPD's aren't used that often, they're typically blended with one of the other resins to lower the cost and help reduce the shrink.

For a typical repair anything but a straight DCPD works well, and you won't be able to buy it, so don't worry about it. Boat builders assemble the entire boat with these standard polyester products, some are chemical bonds and some are mechanical bonds, rarely do they fail. The larger the boat, the more mechanical bonds there are because of the length of time it takes to build them.

Advice on fiberglassing.​

Always check to see how the resin and/or gel coat is supposed to be used, does it have wax added, if it has wax in it you need to apply the next layer before the first one gets hard, if it gets hard you need sand and clean the surface very well before applying the next layer. What catalyst % is recommended (typically from 1% to 2.4%), what do they say about adding other things to it. Don't over or under catalyze and always measure it, don?t use the glug glug method and don't add large amounts of anything to thin them, when you add more than about 5% it can start to have negative affects. Stir well after adding anything, not just a couple swipes with a stick or brush.

While it is important to use good products when doing a repair, it's more important that you use good methods and do it correctly.

Information supplied by ondarvr .​

 

[jcsftwre]

Definitions A - L

Definitions A - L

Definitions of Terms
A

ACCELERATOR?Additive that reduces gel and cure time of
thermosetting plastics such as polyester gel coat and resin.
Also called promoter or activator.

ACETONE?in the context of FRP, primarily useful as a cleaning
solvent for removal of uncured resin from applicator
equipment and clothing. VERY FLAMMABLE LIQUID.
ADHESIVE?Material that unites two surfaces.

ADHESIVE FAILURE?Failure in an adhesive joint that occurs
between the adhesive material and the adherend; contrast
with Cohesive Failure.

ADDITIVE?Substance added to resin mix to impart special
performance qualities, such as ultraviolet absorbers, and
flame retarding materials (waxes, accelerators, etc.).
AIR-INHIBITED RESIN?Resin which cures with a tacky surface
(air inhibits its surface cure).

B

BAG MOLDING?Technique in which composite material is
placed in rigid mold and covered with flexible bag. Pressure is
applied by vacuum, autoclave, press, or by inflating the bag.

BENZOYL PEROXIDE (BPO)?Catalyst used in conjunction
with aniline accelerators or where heat is used as an accelerator.

BI-DIRECTIONAL?Arrangement of reinforcing fiber strands
in which half the strands are laid at right angles to the other
half; a directional pattern that provides maximum product
strength to those two directions.

BINDER?Bonding resin applied to glass fibers to hold them
in position in a broadgoods textile structure. During lamination,
this resin is dissolved by the styrene in polyester resin,
and, if unsaturated, can become part of the final polymer
network.

BINDERLESS CHOPPED STRAND MAT?Textile material
consisting of short glass fibers held together with polymer fiber
cross-stitch; resembles chopped strand mat without the
binder. Also called Stitched Chopped Strand Mat.

BLEEDER CLOTH?Layer of woven or nonwoven material
(not part of composite) that allows excess gas and resin to
escape during molding process.

BLEEDING?Result of softening of backside of gel coat (typically
by laminating resin, or post applied gel coat) which
causes pigments (color) to reflow.

BLEED OUT?Excess liquid resin appearing at the surface,
primarily occurring during filament winding or from an RTM
mold tube.

BOND STRENGTH?Stress required (as measured by load/
bond area) to separate a layer of material from another material
to which it is bonded. Also, amount of adhesion between
bonded surfaces.

BRIDGING?Condition that occurs when textile or sheet
material does not conform to inside edge or radius on mold
or laminate surface.

BUCKLING?Failure mode usually characterized by fiber
deflection rather than breaking.

BULK MOLDING COMPOUND (BMC)?Premixed blend
of thermosetting resin, reinforcements, catalysts and fillers
for use in closed molding process. Similar to sheet molding
compound (SMC), but mechanical qualities are not as good
and it is less expensive.

C

CARBON (OR GRAPHITE) FIBER?Reinforcing fiber known
for its light weight, high strength, and high stiffness.

CARBOXYL?Chemical group characteristic of organic acids,
which are incorporated into the polyester reaction process.

CAST POLYMER?Non-reinforced composite (resin used
without reinforcing fibers). Combines polymers, fillers and
additives as composites to meet specific applications requirements.

CATALYST?In scientific sense, substance that promotes or
controls curing of compound without being consumed in
the reaction (initiator). Within the composites industry, free
radical initiators such as MEKP are often referred to as ?catalysts.?
Such usage is scientifically inaccurate since initiator is
consumed during usage.

CATALYST (PEROXIDE)?In FRP terms, substance added to
resin or gel coat in controlled quantities to make it gel and
cure. Catalyst is reduced by accelerator, creating free radicals,
which in turn initiate polymerization.

CHALKING?Dry, powder-like appearance or deposit on
exposed gel coat surface.

CHOPPED STRAND?Uniform lengths of fibers formed by
cutting continuous strand yarn or roving, usually from 1/32
to two inches long. Lengths up to 1/8 inch are called milled
fibers.

CHOPPED STRAND MAT (CSM)?Uniform lengths of fibers
held together by binder and added to increase composite
part glass skin thickness. Relatively inexpensive, generally
used with other glass mats.

CLOTH?Fine weaves of woven fiberglass.

COBALT?Used as accelerator for methyl ethyl ketone peroxide
catalyzed polyesters.

COHESION?Tendency of single substance to adhere to itself.
Also, force holding single substance together.

COHESIVE FAILURE?Failure of adhesive joint that occurs
either within adhesive material or within one or both adherends.

COMPOSITE?Material that combines fiber and binding
matrix to maximize specific performance properties. Neither
element merges completely with the other.

COMPRESSION MOLD?Mold that is open when material
is introduced and that shapes material by heat and by the
pressure of closing.

CONTACT MOLDING?Open-mold process that includes
spraying gel coat, followed by hand layup or sprayup with
glass and resin. Also called open molding.

CONTINUOUS FILAMENT MAT (CFM)?Textile material
comprising continuous fibers, typically glass, that are swirled
randomly in a construction with more loft than chopped
strand mat for the same areal weight.

CONTINUOUS FILAMENT STRAND?Individual fiber with
small diameter, flexibility and indefinite length.

CONTINUOUS LAMINATING?Process for forming panels
and sheeting in which fabric or mat is passed through resin
dip, brought together between cellophane covering sheets,
and passed through heating zone for cure. Squeeze rollers
control thickness and resin content as various plies are
brought together.

CONTINUOUS ROVING?Parallel filaments coated with sizing,
gathered together into single or multiple strands and
wound into cylindrical package. May be used to provide
continuous reinforcement in woven roving, filament winding,
pultrusion, prepregs, or high-strength molding compounds.
(Also see ?Chopped Strand.?)

CORD, REINFORCING?Loosely twisted cord made up from
rovings and designed for incorporation in moldings where
edge reinforcement and high strength ribs are necessary.

CORE?(1) Central component of a sandwich construction
to which inner and outer skins are attached; common core
materials include foam, honeycomb, paper and wood. (2)
Channel in mold for circulation of heat-transfer media. (3)
Part of complex mold tool that molds undercut parts, also
called core pin.

CRAZING?Cracking of the resin due to internal stress.

CROSS-LAMINATED?Laminated so some layers are oriented
at right angles to remaining layers with respect to
grain or strongest direction in tension.

CURE?Polymerization or irreversible transformation from
liquid to solid state with maximum physical properties, including
hardness.

CURE TEMPERATURE?Temperature at which material attains
final cure.

CURE TIME?Time required for liquid resin to reach majority
of polymerized state after catalyst has been added.

CURING AGENT?Catalytic or reactive agent that initiates
polymerization when added to resin; also called ?hardener.?

D

DELAMINATE?Separation of layers due to failure of adhesion
or cohesion of one component to others. Also includes
separation of layers of fabric from core structure. May be
associated with bridging, drilling, and trimming.

DELAMINATION?Laminate defect that occurs due to mechanical
or thermal stress and is characterized by separation
between laminae.

DIMENSIONAL STABILITY?Capability of substance or part
to maintain its shape when subjected to varying forces,
moments, degrees of temperature and moisture, or other
stress.

DIMETHYLANILINE (DMA)?Accelerator used in conjunction
with BPO catalyst; more effective than DEA.

DIMPLES?Small sunken dots in gel coat surface, generally
caused by foreign particle, air void, or catalyst droplets in gel
coat or laminate.

DOUBLER?Extra layers of reinforcement for added stiffness
or strength where fasteners or other abrupt load transfers
occur.

DRY SPOT?Laminate defect that occurs during molding
process and is characterized by dry, un-wet fibers that have
never been encapsulated by matrix material.

E

EDGE?Geometric feature characterized as line formed
where two panels on different planes come together. When
angle between two panels is between zero and 180 degrees,
edge is inside. When angle is between 180 and 360
degrees, edge is outside.

E-GLASS?Electrical glass; refers to borosilicate glass fibers
most often used in conventional polymer matrix composites.

ELASTICITY?Capacity of materials to recover original size
and shape after deformation.

ELASTIC LIMIT?Greatest stress material is capable of sustaining
without permanent strain remaining after complete
release of stress.

ELONGATION?Increase in length of section under tension
when expressed as percentage difference between original
length and length at moment of rupture.

ENAMEL?Gel coat or surface coat which cures tack free.

ENCAPSULATING?Enclosing article in closed envelope
of plastics) by immersion. Milled fibers or short chopped
strands are often poured with catalyzed resin into open
molds for casting electrical components.

END?Strand of roving consisting of given number of filaments
is considered an end before twisting.

END COUNT?Exact number of strands contained in roving.

EXTENDERS?Low-cost materials used to dilute or extend
higher-cost resins without excessive reduction in properties.

F

FABRIC, NONWOVEN?Material formed from fibers or yarns
without interlacing, (e.g., stitched nonwoven broad goods).

FABRIC, WOVEN?Material constructed of interlaced yarns,
fibers or filaments.

FABRICATION?Process of making composite part or tool.

FATIGUE?Failure of material?s mechanical properties
caused by repeated stress over time.

FATIGUE STRENGTH?Maximum cyclical stress withstood
for given number of cycles before material fails.

FADING?Loss of color in gel coat.

FIBER BLOOMING?Fiber and resin are eroded by weathering
or sandpaper at different rates. Resins erode before
fiber. As a result, fiber rich surface, when sanded, often has
fibers protruding; called fiber blooming.

FIBER CONTENT?Amount of fiber in composite expressed
as ratio to the matrix by weight.

FIBER ORIENTATION?Direction of fiber alignment in nonwoven
or mat laminate; most fibers are placed in same direction
to afford higher strength in that direction.

FIBER REINFORCED PLASTICS (FRP)?General term for composite
material or part that consists of plastic matrix containing
reinforcing fibers such as glass or carbon having greater
strength or stiffness than plastic. FRP is most often used to denote glass
fiber-reinforced plastics. ?Advanced composite?
usually indicates high-performance aramid or carbon
fiber-reinforced plastics.

FIBERGLASS?Fibers similar to wool or cotton fibers, but
made from glass; sometimes call fibrous glass. Glass fiber
forms include cloth, yarn, mat, milled fibers, chopped
strands, roving, woven roving.

FLEXURAL STRENGTH?Strength of material (in bending)
expressed as stress of bent test sample at instant of failure;
usually expressed in force per unit area.

FRACTURE?Rupture of surface of laminate due to external
or internal forces; may or may not result in complete separation.
FRP?Fiber Reinforced Polymers; with evolution of new fibrous
materials, GRP (or GRFP) becomes Glass Reinforced
Polymers term.

FUMED SILICA (Aerosil, Cabosil)?Thickening agent used in
polyesters to increase flow or sag resistance qualities.

G

GEL?Partial cure stage in plastics resins of a viscous, jellylike
state where liquid material starts to transform into solid.

GEL COAT?Surface coat, either colored or clear, providing
cosmetic enhancement and protection for the laminate.

GEL TIME?Length of time that catalyzed polyester remains
workable after hardener is added.

GELATION?Transition of liquid to soft solid.

GENERATION?Term used to describe single step in progression
from concept to master mold to production mold
when molding composite parts with multiple molds from
same pattern.

GLASS TRANSITION?Reversible change in amorphous
polymer between viscous or rubbery condition and hard,
relatively brittle one.

GLASS TRANSITION TEMPERATURE (Tg)?Approximate
temperature above which increased molecular mobility
causes a material to become rubbery rather than brittle.
The measure value of Tg can vary, depending on the test
method. (A widely accepted method is Differential Scanning
Calorimeter?DSC.)

H

HAND LAYUP?Laminating by ?hand? as opposed to using
spray equipment. Usually requires mat and fabric reinforcements
in sheet form.

HARDENER?Substance that reacts with resin to promote or
control curing action.

HEAT?Term used colloquially to indicate any temperature
above ambient (room) temperature, to which part or material
is or will be subjected.

HEAT-CONVERTIBLE RESIN?Thermosetting resin convertible
by heat to an infusible and insoluble mass.

HEAT-DISTORTION TEMPERATURE (HDT)?Temperature at
which test bar deflects certain amount under specified load.
(e.g., temperature at which material softens).

HEAT-PRESSURE LAMINATES?Laminates molded and cured
at pressures not lower than 1000 psi.

HELICAL?Ply laid onto mandrel at an angle, often 45 degree
angle.

HERMETIC?Completely sealed, air-tight.

HONEYCOMB?Manufactured product of sheet metal or
resin-impregnated sheet (paper, fibrous glass, etc.) that has
been formed into hexagonal shaped cells. Used as core
material for sandwich construction.

HOOP?Ply laid onto mandrel at 90 degree angle.

HOOP STRESS?Circumferential stress in cylindrically
shaped part as result of internal or external pressure.

HOT POT?Catalyst is mixed with gel coat or resin in material
container prior to spraying, as opposed to internal or
external gun mixing.

HYBRID COMPOSITE?Composite with two or more types
of reinforcing fibers. Also refers to composite prepared from
a polymer which uses more than one type of chemistry, such
as XYCON? polyester/polyurethane hybrid material.

HYBRID RESIN?Resin with two or more types of chemistries
combined.

HYDROPHOBIC?Moisture resistant capability, moisture repelling.

HYGROSCOPIC?Moisture absorbing capability.

I

IMPREGNATE?Saturation of reinforcement with a resin.

IMPREGNATED FABRIC?See ?Prepreg.?

INCLUSION?Physical and mechanical discontinuity occurring
within material or part.

INHIBITOR?A substance designed to slow down or prevent
chemical reaction; chemical additive that slows or delays
cure cycle.

INJECTION MOLDING?Method of forming plastic to desired
shape by forcibly injecting polymer into a mold.

INTEGRAL HEATING?System in which heating elements are
built into a tool, forming part of the tool and usually eliminating
need for oven or autoclave as heat source.

INTERFACE?Surface between two materials in glass fibers,
(e.g., area at which glass and sizing meet). In laminate, area
at which reinforcement and laminating resin meet.

INTERLAMINAR?Existing or occurring between two or more
adjacent laminae.

INTERLAMINAR SHEAR?Shearing force that produces displacement
between two laminae along plane of their interface.
ISOTROPIC?Arrangement of reinforcing materials in random
manner, resulting in equal strength in all directions.

J

JACKSTRAWING?Prominence of fiberglass pattern having
turned white in the laminate because glass has separated
from resin due to excessive exothermic heat; usually associated
with thick, resin rich laminates. Cosmetic problem
only.

K
KEVLAR??Strong, lightweight aramid fiber trademarked
by Dupont; used as reinforcement fiber.

L

LAMINA?One layer of laminate; can be chopped fiber reinforced
plastic layer, textile reinforced plastic layer, or core
material, etc. Plural is laminae.

LAMINATE (noun)?Panel that consists of multiple laminae
that are permanently bonded together.

LAMINATE (verb)?Action of manufacturing laminate (noun)
by arranging one or more laminae. In FRP, each lamina usually
consists of a fibrous reinforcement and a resinous matrix
material.

LAMINATED PLASTICS?Material consisting of superimposed
layers of synthetic materials that have been bonded
together, usually by means of heat and pressure, to form
single piece.

LAMINATION?Laying on of layers of reinforcing materials
and resin, much like buildup of plywood. Several layers of
material bonded together.

LAYUP?Placing reinforcing material onto mold and applying
resin to it; can be done by hand or by using sprayup
equipment. Layup is sometimes used as a term for the work
piece itself.

LOW-PRESSURE LAMINATES?Laminates molded and
cured in range of pressures from 400 psi down to and including
pressure obtained by mere contact of plies.

LOW PROFILE?Resin compounds formulated for low, zero,
or negative shrinkage during molding.

Information supplied by ondarvr .​

 

[jcsftwre]

Definitions M - R

Definitions M - R

M

MACROSCOPIC?Large enough to be visible at magnification
of 60x or less.

MALE?Archaic term formerly used to describe convex surface
or outside edge or feature.

MAT?Fibrous reinforcing material composed of chopped
filaments (for chopped-strand mat) or swirled filaments (for
continuous-strand mat) with binder applied to maintain
form; available in blankets of various widths, weights, thicknesses
and lengths.

MATRIX?Material in which fiber reinforcements of composite
system is imbedded. Thermoplastic and thermoset resin
systems can be used, as well as metal and ceramic.

MEK PEROXIDE (MEKP)?Abbreviation for methyl ethyl ketone
peroxide; free radical source commonly used as initiator
for polyesters in FRP industry.

MEK (SOLVENT)?Abbreviation for methyl ethyl ketone; colorless
flammable liquid commonly used in spray gun clean
up procedures.

MICRO CRACKING?Cracks formed in composites when
thermal stresses locally exceed strength of matrix.

MICROSCOPIC?Small enough to require magnification
much greater than 10x to be visible.

MIL?Unit used in measuring film thickness and diameter of
fiber strands, glass, wire, etc., (one mil = .001 inch).

MILLED FIBERS?Carbon or glass used for making fiberfilled
putty or BMC strands hammer-milled into short fiber
lengths of 1/32 inch, 1/16 inch, 1/8 inch and 1/4 inch.

MODULUS OF ELASTICITY?Material property that describes
relationship between tension, compression or shear
forces, and deflection experienced by material. Known as
Young?s Modulus for isotropic materials in tension. Modulus
is independent of specimen geometry; therefore, it is a material
property.

MOISTURE ABSORPTION?Pick-up of water vapor from air by
a material. Relates only to vapor withdrawn from air by a material MATRIX
?Material in which fiber reinforcements of composite
system is imbedded. Thermoplastic and thermoset resin
systems can be used, as well as metal and ceramic.

MEK PEROXIDE (MEKP)?Abbreviation for methyl ethyl ketone
peroxide; free radical source commonly used as initiator
for polyesters in FRP industry.

MEK (SOLVENT)?Abbreviation for methyl ethyl ketone; colorless
flammable liquid commonly used in spray gun clean
up procedures.

MICRO CRACKING?Cracks formed in composites when
thermal stresses locally exceed strength of matrix.

MICROSCOPIC?Small enough to require magnification
much greater than 10x to be visible.

MIL?Unit used in measuring film thickness and diameter of
fiber strands, glass, wire, etc., (one mil = .001 inch).

MILLED FIBERS?Carbon or glass used for making fiberfilled
putty or BMC strands hammer-milled into short fiber
lengths of 1/32 inch, 1/16 inch, 1/8 inch and 1/4 inch.

MODULUS OF ELASTICITY?Material property that describes
relationship between tension, compression or shear
forces, and deflection experienced by material. Known as
Young?s Modulus for isotropic materials in tension. Modulus
is independent of specimen geometry; therefore, it is a material
property.

MOISTURE ABSORPTION?Pick-up of water vapor from air by
a material. Relates only to vapor withdrawn from air by a material
; must be distinguished from water absorption, which is
gain in weight due to take-up of water by immersion.

MOLD?(1) To shape plastics parts by heat and pressure.
(2) Cavity or matrix into/onto which plastics composition is
placed and from which it takes its form. Female: Made into.
Male: Made onto. (3) Assembly of all parts that function collectively
in molding process.

MOLD CLAMPING METHOD?RTM process feature that describes
how mold pieces are held together.

MOLD COAT?Coat of resin over bare mold. Used to seal
mold and make smooth surface on which to mold parts. Essentially
the same as a gel coat.

MOLD OPEN-CLOSE METHOD?RTM process feature for
separating mold pieces to allow insertion of dry glass and
removal of finished part.

MOLD RELEASE?A substance used on the mold or in the
compound to prevent sticking and for ease of part release.

MOLD SKIN?Element of cure tool with hard surface that is
polished to high gloss. This surface forms one external face
of production part during molding process.

MOLDING?Forming of part by various means, such as
contact, pressure, matched die and continuous laminating,
into given shape.

MOLECULES?Chemical units composed of one or more
atoms.

MONOFILAMENT?Single filament of indefinite length; generally
produced by extrusion.

MONOMER?A relatively simple compound capable of polymerization
with itself or with a compatible resin. It may also
is be used to dissolve or dilute polyester.

N

NET SHAPE?Part fabrication resulting in final dimensions
that do not require machining or cutting.
NON-AIR INHIBITED RESIN?Resin, cure of which will not
be inhibited or stopped by presence of air, possibly due to
surfacing agent added to exclude air from resin surface.

NON-VOLATILE MATERIAL?Material remaining after heating
to condition short of decomposition.

O

ONE-OFF?Fabrication process in which single part is fabricated.

ORANGE PEEL?Backside of gel coated surface that takes
on rough wavy texture of orange peel.

ORIFICE?Opening, generally referred to regarding spray tip
size.

ORIGINAL EQUIPMENT MANUFACTURER (OEM)?Companies
that design and build products bearing their name.

OUT-GASSING?Release of solvents, volatiles, gasses and
moisture from composite parts under vacuum.

P

PAN (POLYACRYLONITRILE)?Base material in manufacture
of some carbon fibers.

PARALLEL-LAMINATED?Laminated so all layers of material
are oriented approximately parallel with respect to the grain
or strongest direction in tension. Also called unidirectional.
This pattern allows highest loading of reinforcement, but
gives maximum strength in only one direction.

PART CONSOLIDATION?Process of composites fabrication
in which multiple discrete parts are designed and fabricated
together into single part, thus reducing number of fabricated
parts and need to join those parts together.

PARTING AGENT?See ?Mold Release.?

PATTERN?General term for master model that is usually
constructed from single material or material type. Pattern is
generally not durable and suitable for producing only one
(or small number) of molds. Sometimes used interchangeably
with Plug.

PEEL PLY?Layer of material applied to a layup surface that
is removed from the cured laminate prior to bonding operations,
in order to leave clean, resin-rich surface ready for
bonding.

PEEL STRENGTH?Strength of adhesive bond obtained by
stress that is applied ?in a peeling mode.?

PEROXIDES?Category of compounds containing unstable
O-O (or O-OH) Group: Oxygen to Oxygen atoms; used as
initiators.

PHENOLIC RESIN?Thermosetting resin produced by condensation
of aromatic alcohol with aldehyde, particularly
phenol with formaldehyde.

PIGMENT?Ingredient used to impart color, as in gel coats.

PIGMENT SEPARATION?Mottled (varied color) appearance
of gel coat surface.

PINHOLES?Small air bubbles in gel coat film, few enough
to count. Generally larger in size than porosity.

PLASTICS?High molecular weight thermoplastics or thermosetting
polymers that can be molded, cast, extruded or
laminated into objects; major advantage of plastics is they
can deform significantly without rupturing.

PLUG?General term for master model that is usually handcrafted
from variety of materials. Plug is generally not durable;
suitable for producing only one (or small number) of
molds. Sometimes used interchangeably with ?Pattern.?

PLY?Fabric/resin or fiber resin/layer bonded to adjacent
layers in composite.

PLY SCHEDULE?Layup of individual plies or layers to build
laminate (FRP). Plies may be arranged (scheduled) in alternating
fiber orientation to produce multi-directional strength
part (see ?Fiber Architecture?).

POLYESTER (Unsaturated)?Resin formed by reaction between
dibasic acids and dihydroxy alcohols, one of which
must be unsaturated (typically maleic anhydride) to permit
cross-linking.

POLYMER?Large chemical chain composed of many repeating
groups such as polystyrene.

POLYMERIZATION?Chemical reaction of linking molecules
or chains of molecules.

POLYVINYL ALCOHOL (PVA)?Water soluble release agent.

POROSITY?Small air bubbles in composite or gel coat film;
too numerous to count. Generally smaller in size than pinholes.

POSTCURE?Exposure of cured resin to higher temperatures
than during molding; necessary in certain resins to attain
complete cure and ultimate mechanical properties.

POT LIFE?See ?Gel Time.?

POTTING?Similar to encapsulating, except steps are taken
to insure complete penetration of all voids in object before
resin polymerizes.

PREFORM?Preshaped fibrous reinforcement formed by
distribution of chopped fibers by air, water flotation, or vacuum
over surface of perforated screen to approximate contour
and thickness desired in finished part. Also, compact
pill of compressed premixed materials.

PREFORM MAT?Fiber reinforced mat shaped like mold in
which it will be used. Eliminates need for overlapping corners
in molding.

PREHEATING?Heating of compound prior to molding or
casting in order to facilitate operation, reduce molding cycle,
or remove volatiles.

PREMIX?Mixture of resin, pigment, filler and catalyst for
molding.

PREPREG?Resin-impregnated cloth, mat or filaments in flat
form that can be stored for later use. Resin often partially
cured to tack-free state called ?B-staging.? Additives can be
added to obtain specific end-use properties and improve
processing, storage and handling characteristics.

PRE-RELEASE?Premature release of the gel coat or laminate
from the mold.

PRESSURE BAG?Tailored bag (usually rubber sheeting)
placed against the in an open mold, hand layup process.
Air or steam pressure (up to 50 psi) is applied between the
bag and pressure plate located over mold.

PRIMARY LAMINATE??Bulk? or ?second? laminate; laminate
applied after skin coat has cured. Generally thicker than skin
coat.

PRINT-THROUGH?Transfer through gel coat film of image
of glass strands.

PROFILE?Surface contour of part viewed from edge or
cross section. When describing cosmetic features, profile is
the roughness of surface on scale large enough to affect
visual appearance but small enough to be insignificant with
respect to dimensional functionality. Low profile corresponds
to very smooth surface; high profile corresponds to surface
with greater roughness.

PROMOTER?See ?Accelerator.?

PROTOTYPE?Process of creating test part not intended for
commercial release that establishes design, material and
fabrication parameters for new product. May require multiple
iterations (repetitions) to arrive at final/commercial part
design.

PULTRUSION?Automated continuous process for manufacturing
composite rods, tubes and structural shapes
having constant cross section. Roving and other reinforcements
saturated with resin and continuously pulled through
a heated die, where part is formed and cured. Cured part
then automatically cut to length.

R

RAMPING?Gradual programmed increase/decrease in
temperature or pressure to control cure or cooling of composite
parts.

REINFORCED MOLDING COMPOUND?Reinforced compound
in form of ready-to-use materials, as distinguished
from premix, as ?BMC? or ?Gunk.?

REINFORCEMENT?Strong, relatively inert material molded
into plastics to improve strength, stiffness and impact resistance.
Usually fibers of glass, carbon, boron mineral, synthetic
polymer, ceramic, textile, sisal, cotton, etc., in woven
or nonwoven form.

RELEASE AGENT?See ?Mold Release.?

RELEASE FILM?Impermeable film layer that does not bond
to composite during cure.

RESIN?Any of class of natural or synthetic polymers, solubilized
or semi-solid, generally of high molecular weight having
no definite melting point. Used in reinforced products to
surround and hold fibers. Most resins are polymers.

RESIN INFUSION?To draw or force resin into dry reinforcement
already in mold cavity.

RESIN PRESSURE HEAD?RTM process feature; state of
pressure across a part from injection point to vent point;
driving force that causes resin to flow through and saturate
fiber pack.

RESIN RICH?Localized area filled with excess resin as compared
to consistent resin/fiber ratio.

RESIN STARVED?Localized area lacking sufficient resin for
fiber wetout.

RESIN TEARING?Separation of vehicle from pigments/ fillers
in gel coat film, usually seen as black wavy lines.

RESIN TRANSFER MOLDING (RTM)?Molding process in
which catalyzed resin is pumped into two-sided, matched
mold where fibrous reinforcement has been placed. Mold
and/or resin may or may not be heated.

RESIN TRANSFER SCHEME?RTM process feature that describes
pathway used to transfer resins into fiber pack.

RIBBON DIRECTION?On honeycomb core, direction in
which honeycomb can be separated; direction of one continuous
ribbon.

ROVING?Collection of bundles of continuous filaments either
as untwisted strands or as twisted yarns. For filament
winding, generally wound as bands or tapes with as little
twist as possible.

Information supplied by ondarvr .​

 

[jcsftwre]

Definitions S - Z

Definitions S - Z

S

S-GLASS?Magnesia/alumina/silicate glass reinforcement
designed to provide very high tensile strength. Commonly
used in high-performance parts.

SAGS/RUNS?Sag: Slumping of gel coat or resin film. Run:
Running of gel coat film or laminating resin.

SANDWICH LAYUP?Laminate composed of two outside
layers of reinforced material such as glass mat and inside
layer or layers of honeycomb, glass cloth, or other lightweight
core material.

SCRIMP?Seemann Composite Resin Infusion Molding Process.
(See ?Resin Infusion.?) Pulls vacuum before resin entry.

SEALANT?Applied to joint in paste or liquid from that hardens
in place to form seal.

SECONDARY BONDING?Joining together by adhesive
bonding of two or more previously cured parts, or subsequent
lamination onto earlier cured laminate surface.

SET?To convert resin into fixed or hardened state by chemical
or physical action, such as condensation, polymerization,
vulcanization or gelation.

SHEAR?Stress resulting from applied forces. Caused by
two contiguous parts of body sliding, relative to each other,
in direction parallel to their plane of contact. In cross shear,
plane of contact is composed of resin and glass fibers. In interlaminar
shear (ILS), plane of contact is composed of resin
only. In liquids, force and movement of components or layers
against each other.

SHEET MOLDING COMPOUND (SMC)?Ready-to-mold,
glass-fiber-reinforced, thickened polyester material primarily
used in closed molding. Similar to bulk molding compound
(BMC), but with improved mechanical properties.

SHELF LIFE?Length of time uncatalyzed polyester remains
workable while stored in tightly sealed container; also referenced
as ?storage life.?

SISAL?White fiber produced from leaves of agave plant.
Used as reinforcing filler, in short chopped lengths, to impart
moderate impact resistance.

SIZING?Water-soluble solution of chemical additives use
to coat filaments; additives protect filaments from water absorption
and abrasion. They also lubricate filaments and reduce
static electricity (see chapter on ?Open Molding?).

SKIN LAMINATE?Thin, glass laminate applied directly
against gel coat to provide durability by eliminating entrapped
air, and good cosmetic quality by isolating gel
coat from subsequent laminate shrinkage due to exotherm
heat.

SLAVE PUMP?Small, specifically sized pump driven by
master gel coat or resin pump to deliver catalyst in ratio of
one to three percent.

SOLVENT?Liquid used to dissolve and clean materials.

SPEC?Specification of properties, characteristics or requirements
particular material or part must have to be acceptable
to potential user of material or part.

SPECIFIC GRAVITY?Ratio of weight of any volume of substance
to weight of equal volume of some substance taken
as standard unit; usually water for solids and liquids, and air
or hydrogen for gasses.

SPRAYUP?Process in which glass fibers, resin and catalyst
are simultaneously deposited in mold. Roving is fed through
chopper and ejected into resin stream directed at mold. Catalyst
and accelerated resin may be sprayed from one or two
guns. Glass resin mix is then rolled by hand before curing.

STABILIZER?Additive for polymers which aids maintenance
of certain properties.

STIFFNESS?Structural property that describes relationship
between forces and moments applied to, and stretching
and bending deflections experienced by any item.

STRAIN?Deformation resulting from stress.

STRANDS?Primary bundle of continuous filaments combined
into single compact unit without twist.

STRESS?Internal resistance to change in size or shape, expressed
in force per unit area.

STRESS CORROSION?Preferential attack of areas under
stress in corrosive environment, where such an environment
alone would not have caused corrosion.

STRESS CRACK?External or internal cracks in composite
caused by tensile stresses; cracking may be present internally,
externally or in combination.

STYRENE MONOMER?Unsaturated aromatic hydrocarbon,
used in plastics. In polyester, a reactive diluents.

SUBSTRATE?Material on which adhesive-containing
substance is spread for any purpose, (e.g., bonding or
coating).

SURFACE PROFILE?Cosmetic quality of surface (see
?Profile?).

SURFACING AGENT?Material (commonly paraffin wax)
that allows surface of polyesters to cure; limits adhesion of
another coat of resin if first is thoroughly cured. May be removed
by sanding or rubbing with steel wool.

SURFACING VEIL?Used with other reinforcing mats and
fabrics to enhance quality of surface finish. Designed to
block out fiber patterns of underlying reinforcements; also
called ?surfacing mat.?

SYMMETRIC?Laminate design term used with composites
to indicate that laminate is symmetric about the plane, midway
through its thickness.

T

TACK?Stickiness.

TBPB?Abbreviation for tertiary-butyl perbenzoate used as
catalyst (initiator) in high temperature molding of polyester
resin systems.

TBPO?Abbreviation for tertiary-butyl peroctoate used as catalyst
in high speed, heated cures of polyester resin systems.

TENSILE STRENGTH?Maximum stress sustained by composite
specimen before it fails in tension test.

TEXTILE?Any type of sheet material made from fibers that
are woven, knitted, knotted, stitched or bonded together.

THERMAL CONDUCTIVITY?Ability to transfer heat.

THERMAL SHOCK?Temperature changes rapidly, causing
large thermal stresses.

THERMAL STRESS?Occurs when change in temperature
causes materials to expand and contract at different rates.
Can form within and between layers of laminate as well as
between laminate and steel frame.

THERMAL STRESS CRACKING?Crazing or cracking of
some thermoset or thermoplastic resins from overexposure
to elevated temperatures or cyclic temperature variations.

THERMOCOUPLE?Assembly used to sense and record
temperature.

THERMOPLASTICS?Polymers that can be repeatedly softened
when heated, hardened when cooled. Thermoplastics
such as polymers and copolymers of acrylics, PET, polycarbonates,
nylons, fluorocarbons and styrene are fast becoming
important engineering materials.

THERMOSETS?Materials that will undergo or have undergone
chemical reaction, leading to relatively infusible
state. Typical materials are aminos (melamine and urea),
unsaturated polyesters, alkyds, epoxies and phenolics; not
reformable.

THIXOTROPIC?Condition in which material possesses
resistance to flow until it is agitated (mixed, pumped, or
sprayed).

THIXOTROPIC INDEX (TI)?Indication of sag resistance determined
by dividing low shear viscosity by high shear viscosity.
TOOLING GEL COAT RESIN?Special polyesters designed
for moldmaking.

TOUGHNESS?Measure of ability of material to absorb
energy.

U

UNDERCUT?Negative or reverse draft on the mold. Split
molds necessary to shape pieces that are undercut.

UNIDIRECTIONAL?Refers to fibers oriented in the same direction,
such as unidirectional fabric, tape or laminate; often
called UD.

V

VACUUM BAG MOLDING?Molding process for minimizing
emissions voids and maximizing reinforcement content,
forcing out entrapped air and excess resin from layups, by
drawing vacuum into flexible film draped over part. Also
considered ?Resin Infusion.? Vacuum may be drawn after
resin entry.

VACUUM-ASSISTED RESIN TRANSFER MOLDING (VARTM)?
Infusion process where vacuum draws resin into one sided
mold; cover, either rigid or flexible, is placed over top
to form vacuum-tight seal.

VAPOR BARRIER?Material through which water vapor will
not pass readily or at all.

VEIL?Tissue of fibers which drapes and wets easily; of
particular value to provide resin-rich barrier to corrosion or
glass print, as in surfacing veil.

VISCOSITY?Fluid?s resistance to flow.

VOIDS?Laminate defect that occurs during molding process;
characterized by lack of resin material (entrapped air,
un-wetted fibers).

VOLATILE MATERIAL?Material vaporizing under specific
conditions short of decomposition; nonvolatile material remains.

VOLATILE ORGANIC COMPOUNDS (VOC)?Carbon-containing
chemical compounds (e.g., solvents or liquids) that
evaporate readily at ambient or process temperatures. Environmental,
safety and health regulations often limit exposure
to these compounds, so low VOC content is preferable.

W

WARP?Yarns running lengthwise and perpendicular to the
narrow edge of woven fabric.

WARPAGE?Dimensional distortion in composite part.

WATER JET?High-pressure water stream used for cutting
polymer composite parts.

WAX?Mold release agent or surfacing agent.

WEAVE?Pattern by which fabric is formed from interlacing
yarns. In plain weave, warp and fill fibers alternate to make
both fabric faces identical. In satin weave, pattern produces
satin appearance with warp roving crossing over several fill
rovings and under next one (e.g., eight-harness satin would
have warp roving over seven fill rovings and under eighth).

WEAVE PRINT?Extreme form of fiber print resembling architecture
of woven or stitched glass ply just below or near
gel coat surface.

WEFT?Yarns running perpendicular to warp in woven fabric.

WET LAYUP?Application of liquid resin to dry reinforcement
in the mold.

WET WINDING?Filament winding wherein fiber strands
are impregnated with resin immediately before they contact
mandrel.

WETOUT?Process in which reinforcing material can be
completely saturated with resin. Rate usually determined
visually and measured in elapsed time.

WETTING AGENT?Surface-active agent that promotes wetting
by decreasing cohesion within liquid.
WHISKER?Short single crystal fiber or filament used as reinforcement
in matrix.

WIND ANGLE?Measure in degrees between direction parallel
to filaments and established reference.

WINDING PATTERN?Regularly recurring pattern of filament
path in filament winding after certain number of mandrel
revolutions.

WIRE MESH?Fine wire screen used to increase electrical
conductivity. Typically used to dissipate electrical charge
from lightning or electromagnetic interference.

WITNESS MARK?Defect in gel coat surface profile that corresponds
to some feature, either in underlying laminate or
on/in molding surface; sometimes called mark-off.

WOVEN ROVING FABRIC?Heavy fabrics woven from continuous
filaments in roving form. They drape well, are quickly
impregnated are intermediate in price between mats and
yarn cloths, and contribute to higher glass content.

WOVEN TAPE?Tape of various thicknesses woven from
continuous filament yarns.

WRINKLE?Imperfection in surface of laminate that appears
to be crease in one of outer layers; occurs in vacuum-bag
molding when bag improperly placed.

X

X-AXIS?Axis in plane of laminate used as zero reference.

Y

Y-AXIS?Axis in plane of the laminate perpendicular to the
x-axis.

YARN?Twisted strand of roving.

YOUNG?S MODULUS?Ratio of normal stress to corresponding
strain for tensile or compressive stresses less than
proportional limit of material.

Z

Z-AXIS?Reference axis normal to laminate plane in composite
laminates.

Information supplied by ondarvr .​

 

[erikgreen]

Re: Let?s make this a fiberglass information thread!

A couple things that I think you might want to do some research into:

1) Epoxy->poly bonding. Epoxy is an excellent glue. If you bond epoxy over poly, it's true that the whole assembly is only as strong as its components, but the weakest component is the polyester glass. IE, if you bond it properly and pull it apart, what will fail is usually the glass components themselves, not the bond. One side or the other pulls apart, somewhere in the parts that you were connecting. If you had a bond fail where little bits of poly and glass ended up stuck to the epoxy, you didn't have a good bond in the first place.

2) Use of epoxy in amateur boat repair. On the one hand, you're correct that most boats are poly to begin with, but the logic of "it was built with poly, poly is good enough" isn't quite true. Polyester resin is a good molding compound, IE it's great for making strong molded items from. If you get a chemical bond between parts (as you do when molding a whole hull, it all hardens at once) then you have good strength. If you attach more poly to an already cured part, you have a mechanical bond only, which is weaker than chemical. You're right that done properly it's plenty strong enough for boat repair, in most cases. I'd still be worried about major hull repairs... here's why.

"Done properly" is the key phrase here. Almost all amateur boat repair folks and many pro shops don't know how to properly prep and repair with poly. Which is why so many people tell horror stories about poly over poly bonds failing. That's why I usually recommend epoxy for boat repair. It isn't that poly is too weak, it's that epoxy "forgives" many sins as far as proper use goes due to the fact that it's such a good glue.

It's also worth noting that some boats are built with epoxy to start.. those made with exotic fabrics are, since poly generally won't bond those. Also, a lot of home built boats are epoxy since, again, it's forgiving stuff for inexpert users, and they usually have a huge margin of strength in the design. Since you can't bond poly to epoxy strongly (yeah, there are exceptions, but generally...) you use epoxy to repair those.

Erik

 

[ondarvr]

Re: Let?s make this a fiberglass information thread!

Eric


I think what your saying was discussed in the post you're referring to.


1. and 2. are kind on the same topic.
I?m not sure exactly where you were going with this part, but if you have bits and pieces of both sides failing, then the bond was pretty good, it shows both sides were failing at about the same rate and for the most part not at the bond line itself. What you?re seeing is the mechanical bond over powering the chemical bond in some locations resulting in failure of the chemical bond within the laminate.

Larger boat and yacht hulls are commonly extended many feet, sometimes during production and sometimes at a later date, this is normally done with polyester and all of the bonds are mechanical. The issues with secondary bonding came to a head when resin chemistry started to change, the newer resins tended to cure more thoroughly at the surface, so even if you laminated over them a few days later the bond could possible be poor. This was compounded when people used poor methods of construction or repair.

The difficult thing to determine for the average person is how much difference is there between the strength of polyester and epoxy, or between chemical and secondary mechanical bonding.

There is a difference in strength between polyester and epoxy, with epoxy being much stronger in most situations, but what's been proven over many years of production is that polyester is more than up to the job of building and repairing boats. Epoxy should be used when you're building a resin and glass over plywood design, or if you?re building and/or modifying a very very high end performance boat, but even new these high end boats are made with polyester. Very few new boats are made with epoxy, I would guess it?s less than 1% and I don?t recall any of the production boats discussed here ever having been made with epoxy, so the odds are very low someone would be doing repairs on epoxy construction. High end canoes and kayaks are the most likely boats people would run into that would be made from epoxy, these would also have carbon fiber and Kevlar construction, but some of these are also made with VE resin.

When it comes to repairs, it?s the same thing, if you?ve never done them before in big enough numbers to become familiar with how strong they can be, it?s hard to know if the difference in strength between secondary and chemical bonding with polyester creates a big issue. People many times choose polyester because it costs less and they want to do a
?cheap and quick? job, this often means they don?t sand or even clean the surface before doing the repair. When this repair fails they blame the resin and then are told to use epoxy because it ?will? stick. Now they clean off all of the previous repair, most of the time needing to sand it off. Having learned a little from the first attempt, they do a better job and this time it holds up, so the epoxy gets the credit. This story gets repeated many times over and it soon becomes "fact" that polyesters don?t bond well even to themselves.
If you look at some of the before pics that get posted on how the previous owners tried to repair rotten floors and transoms you frequently see work done so poorly that it wouldn?t make any difference which resin was used and there are pics of both products failing in the same way.

Don?t get me wrong, epoxy does bond better, but polyester bonds well enough to do most any repair on a polyester boat. The prep work involves cleaning off all the dirt, grease, bilge gunk, wax and anything else that may be on the surface then sanding (grinding) with at least 36 grit discs, this would be the same with either resin.

The choice of resin is up the person doing the job and most of the time there?s no real right or wrong product, both will work, and if even ?some? care is used in doing the job neither product will fail.

 

[jcsftwre]

Powdered Resin Fillers & Fiberglass Additives

Powdered Resin Fillers & Fiberglass Additives

Powdered Resin Fillers & Fiberglass Additives​

Aerosil-Cabosil
(Fumed Silica) ( Aer-o-sil 200 )

Thickening agent for epoxies, polyesters, and urethanes. Thicken resins to your own taste by adding varying amounts. Ideal for making adhesives and putties for gluing wood, fiberglass, stone, concrete, etc. However, adding this product will make the cured resin much more difficult to sand.


Q-Cells

Inorganic hollow spheres added to resins that will allow for a smoother paste than glass bulbs. Can be used with polyesters or epoxies to fill surface holes and allow for easy sanding. Not for use below waterline.

SM Fairing Compound

Blend of multiple fillers that when mixed with epoxy resins are ideal for multipurpose fairing, filling and sanding. Good for fine and large surface filling that needs a easy sanding, creamy putty.

1/4" Chopped Strand

This material consists of 1/4" chopped fiberglass. Used to increase strength especially in tight corners.

ATH - Alumina Trihydrate

Hydrated aluminum powder can be added to epoxy, polyester and urethane resins for dispersing heat while resin cures in larger castings.

3M Glass Bubbles
(K-25)

These hollow glass microspheres can be added to any epoxy and polyester resin. These bubbles will make a lightweight, easy sanding putty for minor surface filling of cracks, holes, etc.

Phenolic Microballoons
(BJO-0930)

These red/purple color Phenolic spheres when mixed with epoxy resins will create a low density paste compound which will sand easily and improve strength/flexibility of the cured resin. Better for large gap filling.

1/32" Milled Fiber

Milled fiberglass powder added to epoxies and polyesters to increase strength of putty and add surface toughness/hardness.

1/4" Chopped Strand

This material consists of 1/4" chopped fiberglass. Used to increase strength especially in tight corners.


1/2" Chopped Strand

Longer strands than the 1/4" and will provide a coarser mixture that will also give a stronger reinforcement.


Talc

Lowest cost filler for thickening polyester and epoxy resins but will add significant weight over fillers such as Cabosil. Talc also can be applied to skin to help prevent itching when working with fiberglass.