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gelcoat over raw marine ply?

Posted: Oct 13th, '20, 09:54
by ktm_2000
Hi All,

I was planning out how I would mount all the wiring inside my doghouse. I have some scrap 13mm marine plywood and was going to bond it in, one piece of each side of the inside of the doghouse under the helm area. The area will be fairly protected but may get spray over time as the deck is washed down. At some point I will get a door like this one made to keep most spray out https://www.boatoutfitters.com/lift-out ... h-toe-kick.

I would also like to keep the wiring area clean and neat so I was thinking of having a gelcoat surface and was wondering if I could get away with skipping a few steps of glassing with 1.5oz mat and fairing.

Your thoughts? am I going overkill, maybe just sand and put bilgecoat paint on the board?

Re: gelcoat over raw marine ply?

Posted: Oct 13th, '20, 10:57
by Stephan
Matt-
I would expect the marine ply to absorb some of the lighter elements of the gelcoat and might compromise it. I also expect the grain and imperfections will show through.
If you are ok with a rougher finish maybe just paint the marine ply with raw epoxy (non blushing would save a step of prep for the gelcoat) first.
Formica worked for me in expediting the fairing of cockpit panels (http://bertram31.com/newbb/viewtopic.ph ... ls#p112159)
Thank you for the help with this great resource.
Stephan

Re: gelcoat over raw marine ply?

Posted: Oct 13th, '20, 12:32
by CamB25
My panel is white starboard. No finishing required!

Re: gelcoat over raw marine ply?

Posted: Oct 13th, '20, 17:45
by Bruce
Matt,
Once a screw is put into it, gelcoat, glass overlay wont matter moisture intrusion will start.
There are so many composites available now there's no reason to use wood.

Re: gelcoat over raw marine ply?

Posted: Oct 14th, '20, 07:56
by John F.
I agree with Bruce that your better off with composite. That said, I built the center console for my 20 out of marine ply. Saturated inside and out with epoxy (2 thinned costs and 2 full strength), glasses seams inside and out, and a layer of cloth on the outside. Then, fair over the cloth and paint. Hopefully, composite will be less work

I didn’t paint the inside of my center console. With it unpainted it’s easier to see any problems, like rot. I haven’t had any.

And I built a mock up out of cheap ply to see how it fit the boat and me. I made a few significant adjustments based on the mock up.

Good luck.