How much fiberglass and resin

[109jb]

Well I'm finally starting on the deck replacement on my 16 foot Sea Ray Seville. I'm getting ready to order some materials and I've kind of roughly figured that I need 30 yards of 50" wide 1.5 oz CSM and 10 gallons of resin. I figured that amount based on one layer of CSM on the bottom and 2 layers on the top of the deck. The 2 stringers are about 7" tall at the tallest location and will get 2 layers of CSM. Was just wondering if someone that has done a similar size boat can tell me if I'm in the ballpark.

 

[Yacht Dr.]

Re: How much fiberglass and resin

hello 109..

Well for sure I can tell you how much 30 yards (90') x 50" (4.16') x 1.5 oz mat will need for resin... that would be about 18-20 Gallons ( depending on how much substrate takes ).

YD.

 

[109jb]

Re: How much fiberglass and resin

Really??? According to the sticky at the top of the forum it says 3 to 4 oz of resin per sq ft of 1.5 oz CSM. A 50" wide roll is 4.16 feet and 30 yards is 90 feet. 90 x 4.16 = 375 sq ft of CSM. 375 X 4 = 1500 oz of resin. Then 150 oz per gallon means 1500/150= 10 gallons. So, is the sticky wrong??? Am I missing something? I also found the same ratio of 4 oz resin per sq ft of 1.5 oz CSM and several different supplier websites.

 

[Yacht Dr.]

Re: How much fiberglass and resin

Its actually 128 oz/gl ( water/milk a gallon ) which is about 12 gals m8..

now in my experience .. you will waste about 1/8 in resin ( if not WAY more if you dont have to buy it and doing smaller layups .. which you will..) but on typical "lets go and glass" you will have waste..more then you know..

Im saying .. anticipate ( you asked ) 25% more than what you Think it will take.

Your not a 20 year " hand layup in prime conditions " kinda guy....you will not know..and then run out of resin .. ? Trust me.. you need (will use ) 15... gal to wet out 30 yards of 1.5 oz mat.

Unless you have time to ... have time..to do it one .. square .. foot .. at time..

Trust ol' YD..

 

[109jb]

Re: How much fiberglass and resin

Actually, according to the sticky a gallon of resin WEIGHS 150 oz and the 4 oz is a WEIGHT of resin per sq ft of CSM.

That wasn't my question though. Let me put it this way. Is 30 yards of the CSM about right for a 16' V-hull boat with one layer on the bottom of the deck and 2 layers on top plus the stringers.

 

[Yacht Dr.]

Re: How much fiberglass and resin

Actually, according to the sticky a gallon of resin WEIGHS 150 oz and the 4 oz is a WEIGHT of resin per sq ft of CSM.

That wasn't my question though. Let me put it this way. Is 30 yards of the CSM about right for a 16' V-hull boat with one layer on the bottom of the deck and 2 layers on top plus the stringers.

Your sparring..please do put pics up..

Get your glass ..and add 10-25% more resin in your order.

Im just saying..

YD.

 

[Mark42]

Re: How much fiberglass and resin

Coverage chart by resin/type of glass:

http://www.fiberglasssite.com/servlet/the-68/Fiberglass-Information,-and-How/Detail

 

[109jb]

Re: How much fiberglass and resin

Your sparring..please do put pics up..

Get your glass ..and add 10-25% more resin in your order.

Im just saying..

YD.

It was not my intent to come off as sparring, I was only clarifying that the 150 oz/gallon I referred to was a weight per gallon.

The trouble I have is that your estimates are 2X what the suppliers say. You may be absolutely right and I don't mind ordering a bit extra, but I really don't want to be stuck with an extra 8 to 10 gallons ($300 +) of resin that I will never ever use.

I guess I'll order the 30 yds CSM and 10 gallons resin and see how far each goes. If I have to order more then so be it. That will definitely give me enough to get the stringers in and the bottom of the deck glassed. At that point I will see how much CSM I've used and how much resin and decide if i need to order more.

Thanks.

 

[109jb]

Re: How much fiberglass and resin

Coverage chart by resin/type of glass:

http://www.fiberglasssite.com/servlet/the-68/Fiberglass-Information,-and-How/Detail

Yep. That's one of the websites I found that said 4 oz resin per sq ft CSM. Using that calculation, 1 gallon should be able to do 3 running yards of 50" wide 1.5oz CSM. I guess I'll have to see if that works out for me.

 

[ondarvr]

Re: How much fiberglass and resin

CSM isn't the only type of glass you need, get some roving or 1708 for strength, both use less resin and offer more strength than CSM. The amount of resin needed will vary greatly on how experienced you are and just what you're doing. Glassing over wood will require more resin, as it needs to be
pre-coated and some will soak in. 4oz's per square foot of mat will allow for some waste, but most people end up using more than they first estimated.

 

[109jb]

Re: How much fiberglass and resin

I have a roll of fiberglass cloth, but I guess I don't understand why I would need it since the original construction didn't have any cloth in it. As a matter of fact, the deck didn't have any fibers at all on the bottom side. It appeared to only have a coating of resin. There was certainly no cloth anywhere that I found.

 

[Mark42]

Re: How much fiberglass and resin

I have a roll of fiberglass cloth, but I guess I don't understand why I would need it since the original construction didn't have any cloth in it. As a matter of fact, the deck didn't have any fibers at all on the bottom side. It appeared to only have a coating of resin. There was certainly no cloth anywhere that I found.

And what is the condition of the original deck now?

 

[109jb]

Re: How much fiberglass and resin

And what is the condition of the original deck now?

Well you can't really judge the condition now because the boat was not taken care of AT ALL.

When I bought it it had about 4 inches of wet soaked mulch that used to be leaves from trees. It also had 3 inch screws that held a homemade fishing platform that went straight through the deck and then through the hull. Someone must have replaced the fuel sender because they chopped a one foot square hole through the original deck underneath the homemade fishing deck and then did absolutely nothing to attempt to seal the edges of the wood. There was obviously no cover anywhere in sight. I found screw holes in the deck where seat bases were moved around and not sealed. I am actually amazed it held up as well as it did.

I actually bought the boat strictly for the outboard motor which unlike the rest of the boat was in really good condition (1997 Mariner 115 HP looks like new and all cylinders above 120 on compression and it runs real good.) I was originally going to just dump the boat, but I first wanted to exercise the motor so I cleaned it up enough to put it in the water and fell in love with its handling and ride and decided I could fix it. I only gave $1200 for the whole boat/trailer/motor.

Once done I will be taking good care of the boat as it will always be in my pole barn when not being used. I guess I figure that if the original stood up to the mistreatment that it did for the last 20 years it couldn't have been that bad the way it was built and would only be better.

One thing I may do though is use change the top deck layup from 2 layers CSM to 1 layer CSM and one of the 8 oz cloth I have.

 

[chrishayes]

Re: How much fiberglass and resin

The 1708 or roving that ondarvr is talking about is used primarily where there will be torsional loads presented i.e your stringers and transom. The 1708 is a biaxially woven cloth which provides strength in all directions not just north south like roving. I can attest to its ability to provide torsional strength. I just ground my hull with a buddy and he decided that he should grind REALLY well and took the glass down to almost gelcoat! SO I laid a layer of 1708 along with 8.5oz tabbing over the entire hull on the inside. Before this when you stood in the boat you could feel the hull flexing down under foot and also the whole hull could easily be "twisted" torsionally. Now with the 1708 on there is no more flex under foot and the twist has been reduced to a level lower than it was before grinding. This will probably all but dissapear once the stringers are in and glassed with the same 1708 and tabbing. I reccomend you look into this product, you wont be let down. www.uscomposites.com

 

[109jb]

Re: How much fiberglass and resin

I fully understand that cloth, biaxial, roving,etc. all produce a laminate that is stronger than CSM. I am actually not a complete greenhorn when it comes to composite layup, nor am I an idiot when it comes to structures since I am an aeronautical engineer and have worked on design of fighter aircraft, and have built composite parts for homebuilt airplanes. That is why I have a roll of 8 oz cloth. In those aspects, I would not even consider CSM or polyester resin because the strength to weight ratio is not there.

Having said that, my goal is not to make this boat MORE structurally sound than new, but to make it AS structurally sound as new as cheaply as possible. Seems to me that in order to accomplish this goal I would need to duplicate the materials that were used in the original construction since I'm sure the manufacturer used the cheapest way. The original was chopper gun applied fiberglass/polyester. The closest you can get to that in a hand layup is CSM using polyester resin. Saying 1708, or roving, or whatever is better, stronger, faster is very true and I don't argue that. What I question is if it is needed since the cost is obviously much higher for the materials (remember, as strong, as cheaply as possible). Unless I am totally missing something then I don't see that it is needed. I'm not trying to argue or be combative, just trying to understand your logic. If you are trying to take a boat and make it MORE structurally sound than original then I can see using the 1708 or roving. If only wanting to be "AS" sound as original is there a need. I don't see it.

As far as torsional rigidity, the deck/hull combo is what provides that. A boat hull without a deck or stringers is about the worst structure I can think of in terms of torsional rigidity. The deck closes off the structure making a tube of sorts. Actually in the case of my boat with 2 stringers, there are 3 connected tubes side by side. These tubes do have good torsional rigidity. The structural joint between the deck and the hull or stingers and hull will be in shear when the hull tries to twist. The joint has to be able to take this, but the joint is long and pretty much the entire length takes this load. A joint of fibers 45 degrees to the joint to connect the plywood to the hull would be best, but again, I don't see it as necessary unless you are trying to make the structure stronger than original.

Maybe I'm missing something here. If I am enlighten me, but I don't see why anything but CSM is required to duplicate the original. My feeling is that if any boat is taken care of properly it will last. I have a friend that has a Sea Ray I/O that his father bought new in the early 80's. His boat has always been stored in a garage and has always been taken care of and except for a few dock dings it looks like new and everything is as solid as the day his father bought it. A boat that is well cared for will last and a boat that is neglected will not. I believe this is true no matter how well it is constructed.

 

[rucaradio]

Re: How much fiberglass and resin

Had to go to my local "transom/stringer/floor" repair shop the other day to pick up a fiberglass roller and the guy looked at me like I was crazy when I told him I was using 1708 for the transom and stringers on my project. "I don't think you need biax for that project", he even went as far as to say I didn't need mat at all... just CSM or cloth. I explained I was using poly resin, and he said that didn't matter.... Either all the iBoats posts I read were wrong, I'm confused, or this guy doesn't know fiberglass..

 

[ondarvr]

Re: How much fiberglass and resin

You're correct, no need to make it stronger than stock if it held up with no issues. I like that line of thought and try to convince people there's no need for exotic materials and epoxy when the structure held up for 30 years of use with no failures.

The problem is we can't see your boat, we can only go by what information you give us, we then fill in the blanks with experience we've gained over the years from similar situations. Many people that post questions don't know any thing about F/G and don't know the difference between mat, roving, cloth, epoxy, polyester, etc. So when they talk about fabrics we need to find out what they know. We didn't know your background, so we needed to start from scratch with our communications and assume you have no background in composites.

Your hull has stringers that were chopped over, that means every boat made of your model would be different. because each chopper gun operator will apply a different amount of glass in a different pattern, some areas end up with little or no glass and other may be 1/2" thick. We can't see it, so we can only suggest what would be an appropriate laminate schedule for a stringer in a boat that size.

One or two CSM makes for thin laminate 1/8" + - and not very strong, adding a layer of roving, or any other fabrics mentioned so far will make it much stronger and possibly easier to work with. Since you have a roll of cloth, use that to ensure it will hold up even if its not needed. The higher cost of using these fabrics is somewhat offset by the fact that they require about 50% less resin and offer much more strength.

 

[rngale]

Re: How much fiberglass and resin

He may not be wrong if the cloth he is referring to is backed with mat already. Mat is the binder that ensures a good bond between layers of glass where the layer underneath is cured. If you were to do say straight woven roven cloth with out a mat backer then you would have to put down a may layer first then while still wet and your woven roven on top of the wet mat and you can continue to add layers of woven while your layup is still wet.

In response to your resin/ cloth ?. the perfect layup is a 60% cloth to 40% resin mix. That is not easy to achieve when trying to learn how to do it. It is safer to have extra resin on hand then to run out in the middle of a layup. Most experienced ppl end up with a 50/50 mix.

Hope that helps and doesnt add to the confusion if it did i apologize

 

[jonesg]

Re: How much fiberglass and resin

Familiarity breeds contempt ,
for the design "engine ears" among us mat is plenty good enough (except to prevent cosmetic blisters I think) , knowing the forces at play really helps.

for the rest of us, glass cloth and other exotic weaves are insurance against not knowing. In boats we only need to overcome certain forces.

In aviation theres different rules of thumb.

1 the air is thin.
2 the ground is hard.
3 gravity is always working.

 

[109jb]

Re: How much fiberglass and resin

OK. I see now. I haven't go the floor up yet as that is this weekends project. I think what you are saying is that once i get to the stringer/hull and deck/hull joints I going to see that the chopper gun guy probably layed on a ton in the fillets. Easy to do with a chopper gun, but many many layers when using CSM. So, if that is the case, using 1708 or roving in the joint gives the required strength with a thinner laminate (read less work, less resin...). If that is the case then I can see that logic. I haven't got to the joints yet so I can't see how thick the buildup there is.

How does this plan sound then.

Stringers - 2 layers 1.5 oz CSM all over and in the joint to hull and then a 1708 tape (say 4" or 6" wide) at the joints.

Deck - 1 layer CSM on the bottom, then install to boat. Foam the cavities using 3" blowout holes, and then plug the holes. Then 2 layers CSM on top with 1708 tapes over the deck/hull joint.

I think this would be a good compromise and would give the required strength using the minimum of the expensive materials.