Deck, Stringer, Transom Layup Help

[kenny26]

I'm trying to decide on my fiberglass material list and the more i read the more confused i get...

If you have done a restore using on a boat I'd like to know what material layers you used (CSM,Cloth, Roving, Biax, etc) on your deck, stringers and transom and the order of layup.

Example of what i'm looking for (totally made up list):

Type of Boat: <insert brand/model here>
Resin type: Poly
Transom: CSM, Ply,CSM, Ply, 1708 biax, CSM
Stringers: Tabbed with CSM, 1708, 1708
Deck: Tabbed with CSM, 6oz cloth, 6oz cloth

This would help me immensely and could become a resource for others to see what people have used in their restores.

Thanks in advance

 

[lowkee]

Re: Deck, Stringer, Transom Layup Help

I guess I'll begin. NOTE: All CSM is 2.0oz, not standard 1.5oz

1990 Bayliner Capri BR 2050 (20')
Resin: Slow cure poly
Transom: CSM, ply, PL poly adhesive, ply, CSM.
Attached transom to outer skin: PL, new transom, CSM x3
Stringers: Coated ply with Poly, Bedded w/PL, Covered with CSM x2
Deck: Coated with CSM (top and bottom), Tabbed with CSM (tabbed top and bottom of deck)

Is this the best method? Probably not. Will it last forever? Probably. The downside of CSM for all is resin usage. CSM sucks down resin pretty fast, which is a plus or negative depending on your priorities (saving money vs. stop an artillery shell).

 

[drewpster]

Re: Deck, Stringer, Transom Layup Help

I used 1.5 chopped strand mat and 18 woven roving for my stringers, transom and deck. The chopped strand is used to promote a good bond between the substrate and the roving as well as between roving layers. CSM has random strands which make it conform to tight corners and complex bends. When used in conjunction with roving it helps the roving do the same. Roving by itself does not conform well. Csm is also used between roving layers because roving does not bond well to itself. The roving is used to add bulk and thickness and most importantly, strength. It is best to plan your layup so that you lay in CSM layers and roving layers together in wet resin.

A typical layup goes as follows;

2 CSM, 1 roving, 1 csm, 1 roving, 2 csm

This schedule typically yields about 1/14" thickness of finished glass. The top 2 layers of CSM are used to promote a water tight, finishable surface.

For the stringers I used the following

2 CSM, 1 roving, 2 csm

this yields about half the thickness (1/8- 3/16") I found that 1/4" was too much bulk for the tight bends in the corners and the tops of the stringers.

It is best in my opinion to use thickened resin to fillet (round out) all of the inside corners to help the glass lay in to them. It adds allot of work but it is worth it. It prevents voids in the corners that can collect water.

I always finish the last layer with CSM to make it water tight. On a surface you intend to paint, I recommend using a light weight finishing veil over the CSM. Finishing veil is usually sold as a very light CSM or a tightly woven fiberglass cloth.

From memory;
15-20 gallons polyester layup resin (no wax)
15-20 yards 1.5 ounce CSM
10-15 yards 18 ounce woven roving
2 quart pale of 1/4" chopped strand (not cloth just fibers)
3 quart pale of Colloidal Silica (aka areosil, cabasil, fumed silica)
2 quart pale of talc powder
1 50 yard roll of 12"x 1.5 ounce CSM fiberglass tape (very handy with stringers)
3 gallons Acetone
2 gallons MEK

Stir sticks, mixing pots, chip brushes, cheap roller covers, roller pan liners, Grooved Roller, rubber or vinyl gloves, tyvek suit, resperator, safety glasses
I am sure I am missing allot here.

About $1100 bucks if memory serves

This all took me from bare hull to finished fiberglass on a 16 foot tri-hull. (thundercraft link below) I have no resin left but I do have fiberglass.
enjoy
drewp

 

[drewpster]

Re: Deck, Stringer, Transom Layup Help

BTW- The example I outlined above can be considered giant overkill, but that is my nature. All the info I used to come up with my plan was taken from friends I have made here as well as a book "The Fiberglass Boat Repair Manual" by Allan H. Viatses. I had a concern about adding weight. Before I started I could lift the hull off its stand by hand, now I can still lift it but takes more effort. (the redneck scale) I am confident that failure is assured.

 

[NSBCraig]

Re: Deck, Stringer, Transom Layup Help

For the transom-

I glassed my ply together with poly and csm, then poly and csm the outside with cloth tape around the edges making the transom piece one solid sealed piece.

Then used poly on the inside skin and transom with some csm in between.
It's as solid as can be.

I personally don't like the pL idea to attach the transom but others love it.

Fillet and tab the transom in with 1708 tape.

Then when your covering the inside of the transom the only thing your worried about is making a protective layer.

 

[erikgreen]

Re: Deck, Stringer, Transom Layup Help

Here's my current standards. Note that I've just started using some of these, specifically the biax without mat. Note also that I only use epoxy.

My method of glassing may be different from other folks. I cut all glass to shape/length first then pile it up near me to work. I use a foam roller to coat the wood first, let it sink in a little, then put the fabric in place and align as needed. Then I wet out using the foam roller. I always work wet on wet when possible... for example, stringers go in on spacers, are checked for position and clamped in place. Then I apply the putty, fillet it, wet, apply glass 3x layers of tabbing, then apply the overall cover of glass or epoxy in one go.

Transom: 2 layers of plywood glued together and into place with putty (epoxy, cabosil, microbubbles). Filled edge gaps with putty for fillet, then Tabbed around edges with 17 oz biaxial fabric (no mat) in 3 layers. Transom then covered overall and overlapped to sides with 8 oz woven fabric.

Stringers: plywood spaced off deck with plastic spacers. Filled stringer/deck crack with putty fillet, then tabbed in place with 17 oz biax tape, 3 layers. Any exposed wood is painted with epoxy and/or covered with 8 oz cloth.

Deck: supporting members get wood cleats attached, 1x1 wood, at top edge. Putty glued and clamped, then painted with epoxy (1 layer). Deck pieces cut to shape and laminated with 1 layer 8 oz woven fabric both sides, then putty glued to support members/cleats. I have used PL premium for this in the past. Deck sections tabbed to hull sides/each other/corners wrapped with 17 oz biaxial fabric. Overall deck covered with fabric or paint.

I use heavier/different fabric occasionally if I have some laying around and I want to save money (there's a great deal to be had on ebay, a guy sells heavy scraps there of 3208 biax) but these fabric weights are my choice for use. Here's why:

17 oz 45/45 biaxial: Strong fabric, stitched together so the fibers are straight, not woven around each other. No mat means minimal resin use, 3 layers of this are strong enough for just about any use in a boat this size. Make sure to alternate fiber directions between layers.

Edit: "this size" means my boat, a 20 footer.

8oz cloth: You need a minimal thickness fabric to cover wood for sealing and abrasion resistance. I happen to have a big roll of this from a great ebay deal a while back. When I run out I'll probably switch to something a bit lighter, stitched if I can find it for easier handling. Basically the lighter the fabric, the less resin you use, and the lighter the whole part is.

If I'm molding something (which I do rarely) or I just want to build up a thick piece of fiberglass for something, then I use things like 3208 biax, spare roving, mat, or whatever. That's if only thickness matters, not tensile strength or flexibility.

You'd be surprised how little actual fiberglass is enough to make a plywood panel very, very strong....

Erik

 

[NSBCraig]

Re: Deck, Stringer, Transom Layup Help

"You'd be surprised how little actual fiberglass is enough to make a plywood panel very, very strong...."

So true.