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Elastomeric Paint

PostPosted: Fri Jul 03, 2009 8:32 am
by Notsomad Max
Anybody try elastomeric paint over epoxy? I have 4 coats of epoxy over exterior spruce plywood and am still getting small cracks in the plywood. I am thinking a good stretchy paint ma be the best choice.

PostPosted: Sun Jul 05, 2009 1:50 am
by kennyrayandersen
I think that the cracking is very difficult to eliminate with only paint. This topic comes up a lot on plywood boat building. Surprisingly, building a water-tight trailer and a boat aren't so different as it might seem. Anyway, a lot of the guys who paint only without using a thin layer of fiberglass experience cracking problems (and subsequently water damage).

The fiberglass industry makes a pretty thin fabric, which can cover the wood without obscuring so much of the grain detail etc., but the biggest benefit is that it reinforces the finish and stops the cracking. I'm not sure how else to do it. :thinking:

PostPosted: Sun Jul 05, 2009 2:13 am
by madjack
Max, a question...what is the epoxy coated/covered with at present...epoxy is not UV proof and needs some sort of covering to give it that protection...spar urethane, auto clear and marine urethane paint are the most common.......
madjack 8)

Elastomeric paint

PostPosted: Sun Jul 05, 2009 7:45 am
by Notsomad Max
As it sits now I just have the epoxy coating.
It's under a tarp to keep the uv off and rain as it's been raining here for a month.. I didn't want to use glass cloth because of the mess and the lack of experience i have working with it. I has 4 coats of west system over it now. The elastomeric paint I enquired about will stretch 1/8 of an inch. Not sure if it will peel off though.

PostPosted: Sun Jul 05, 2009 8:23 am
by kirkman
I used this koolseal on the lid of my utility trailer. The person who built the Zephyr whose name escapes me at the moment also used is on there tear. (It's a elastomer roof coating.) I put it on my plywood dump trailer lid to see how well it holds up under real hard use/abuse. So far so good after 6 months. No chips cracks or leaks I think I will use this on my next build. I paid $ 25 for 1 gallon. Which was more than enough to do a tear with two coats. Just a thought :thinking:

PostPosted: Sun Jul 05, 2009 8:26 am
by kennyrayandersen
I don't think the fiberglassing is so hard -- there are lots of tips and instructions on this and other websites as well as the Raca website. I would do it and follow up with a UV coat, but that's me. Mad Jack is also absolutely right about having to coat it with some kind of UV protectorant regardless if you go with the fabric or only the topcoat of whatever. I would check though for compatibility between the two products.

Elastomeric Paint

PostPosted: Sun Jul 05, 2009 11:25 am
by Notsomad Max
I like the idea of elastomeric paint as I have to paint it any way and if I can avoid the glass cloth thats a bonus. Does this type of paint dry to a smoth matt finish? if I were to use a light cloth what would be a good weight I've read it goes from 2 ounces to 40.

Re: Elastomeric Paint

PostPosted: Sun Jul 05, 2009 5:42 pm
by kennyrayandersen
Notsomad Max wrote:I like the idea of elastomeric paint as I have to paint it any way and if I can avoid the glass cloth thats a bonus. Does this type of paint dry to a smoth matt finish? if I were to use a light cloth what would be a good weight I've read it goes from 2 ounces to 40.


go with the lightest weight (2 oz) stuff as it's not being used structurally, just giving the finish integrity. :thumbsup: