Help Understanding Epoxy For Sealing Wood

[Mike46]

I too have been using West Marine products for many years. I use it everyday in a Unlimited Hydroplane Race Shop. It's a consistently excellent product. At 200 mph we only use the best. It's the only thing I'll use on my build.

What's your cover coat of choice over the epoxy? Rated for 200 mph of course.

Thanks, Mike

[Atomic77]

I use DuPont 33430S Primer/Filler. I level out the epoxy with 180 then 220, fill any pinholes with 3M Platinum Filler, then 2 or 3 medium coats of Primer. I'll level out the Primer with 220,320 dry then 400 wet. Apply DuPont 7740S Sealer then Basecoat/Clearcoat. This is the same process I plan on using on my trailer.

[Mike46]

I use DuPont 33430S Primer/Filler. I level out the epoxy with 180 then 220, fill any pinholes with 3M Platinum Filler, then 2 or 3 medium coats of Primer. I'll level out the Primer with 220,320 dry then 400 wet. Apply DuPont 7740S Sealer then Basecoat/Clearcoat. This is the same process I plan on using on my trailer.

Is there any glass in your process in order to go 200 mph. I’m thinking about how to cover my all plywood build, I thought about a clear coat of poly to UV protect the epoxy, but worry about the plywood cracking, I’ve heard about in this forum. Primer and paint sounds like a safer way to go. How would you change you process if you could not spray on your Primer, Sealer, Base and Clearcoats?

Thanks, Mike

[Atomic77]

The boats are conducted from Carbon fiber. In my build I'm going to lay Carbon tape on the seams and epoxy the rest. Honestly Mike I won't do it any other way besides spraying it. So I can't be helpful with that. I got hooked into a repair for another team in the pits, where they had rolled on the primer. It was so much harder to prep for paint. Where do you live maybe we could do a clinic?

[kayakdlk]

Is there any glass in your process in order to go 200 mph. I’m thinking about how to cover my all plywood build, I thought about a clear coat of poly to UV protect the epoxy, but worry about the plywood cracking, I’ve heard about in this forum. Primer and paint sounds like a safer way to go. How would you change you process if you could not spray on your Primer, Sealer, Base and Clearcoats?

Thanks, Mike

If you use 3-6 oz fiberglass cloth with epoxy it will keep the plywood from checking (cracking). You can use the same process as spraying but roll on boat primer/paint if you want a smooth surface (sand between coats). I suggest a two part paint for longer gloss and durability. The Little Swiss build http://littleswissteardrop.com/thesides.html has a smooth foam roller paint job that looks great. I used his method for my door jamb areas. You can also roll on monstaliner bedliner paint (with no rubber crumbs in the paint) if you want slightly textured extremely durable UV surface. Check out Jeep forms for reviews on Monstaliner durability and check out my build journal for how my teardrop was painted with it.

Dan

[Mike46]

The boats are conducted from Carbon fiber. In my build I'm going to lay Carbon tape on the seams and epoxy the rest. Honestly Mike I won't do it any other way besides spraying it. So I can't be helpful with that. I got hooked into a repair for another team in the pits, where they had rolled on the primer. It was so much harder to prep for paint. Where do you live maybe we could do a clinic?

I'm in the Denver area, a little too far for a clinic unfortunately. Interesting idea about the Carbon tape on the seams, that thought about using glass on the seams crossed my mind. I work in the furniture industry and know that spraying is the way to go, but my space is limited, that’s why I’m building the way I am. Great info, thanks for the tips.

If you use 3-6 oz fiberglass cloth with epoxy it will keep the plywood from checking (cracking). You can use the same process as spraying but roll on boat primer/paint if you want a smooth surface (sand between coats). I suggest a two part paint for longer gloss and durability. The Little Swiss build http://littleswissteardrop.com/thesides.html has a smooth foam roller paint job that looks great. I used his method for my door jamb areas. You can also roll on monstaliner bedliner paint (with no rubber crumbs in the paint) if you want slightly textured extremely durable UV surface. Check out Jeep forms for reviews on Monstaliner durability and check out my build journal for how my teardrop was painted with it.

Dan

I'm going to have some exposed joinery from the half blind box joint I’m going to use and thought it might be interesting to show off the Baltic Birch ply’s. I was hoping to avoid glassing the whole thing, may go the paint route and K.I.S.S. it. Thanks for the bedliner name, I’ll read up.

Mike

[Atomic77]

Because my experience with West Systems is in Marine use, and most of it is over Carbon fiber, I've got a question regarding epoxy over plywood and the checking/cracking Mike and Dan have mentioned. My original plan was 1/8" plywood outer walls skinned with filon. When I started the project I could get 8' filon in a continuous roll for 1.50 per sq ft. In a matter of months the price has gone up to 2.oo per sq.ft. To save money I decided to use filon on the roof, but use 3 good coats of epoxy on the walls. Here's my question: Am I going to run into problems with the plywood checking/cracking or is this mainly an issue on the roof where it gets direct UV, and won't be an issue on the walls, especially since they will be primed, sealed, painted and cleared in Imron which has UV inhibitors.(?) Thanks!

[kayakdlk]

Several builds on here have just used several coats epoxy over the wood without fiberglass cloth except on the seams. Some use CPES. Only time will tell if it alone with paint keeps the plywood from checking. Sun is the most damaging factor, and here in sunny Colorado it is a big factor. I see the damaging results ever summer on my house. The quality of plywood is not what it use to be and even with the supposedly high quality 1/8 Baltic birch (No voids etc) on my build I but went with cloth as added protection from checking and with the 3-4 coats of epoxy it makes the outside nice and strong.

I built my teardrop for 20+ year service. I didn't want with all of the time and money I put into my build to regret in a couple years not spending the $ for the fiberglass cloth. I planned on using 6 oz cloth but used 7 oz as it was on clearance. I think you can use 2 or 3 oz and get the benefits without using the extra epoxy the heavier cloth takes. The way I look at it the epoxy and cloth protects the plywood and the paint protects the epoxy.

Good luck with your build

Dan

[Atomic77]

Thanks Dan. I really want to go all filon, but the cost... Anyone here have any experience using West Systems to bond filon to plywood?

[kayakdlk]

I think most float the filon just like aluminum and use trim pieces to hold on and seal edges. That is what I was going to do before I went with paint.

Dan

[rowerwet]

I read somewhere and I can't remember where, somebody was painting a boat (or outside of a tear) with TBII (or three) mixed with latex paint to give them the waterproof properties of the TBII and the color of the exterior paint. I have not heard any follow up on this, your best bet would be to bite the bullet and use marine epoxy (bateau2.com has it cheaper IIRC) just remember a shower is small and dark, bright walls will make it easier to find the soap...