waterproofing ply with epoxy; with fiberglass cloth or without?

[Darren Nemeth]

I'm about to work on the fin portion of my boat.

Its made of 1/4 inch Douglas Fir ply and, as you can see below, its hollow. I want to protect it from condensation and other moisture with epoxy.

To waterproof the insides of the fin can I use straight epoxy painted on or do I need to veil it with cloth with epoxy?

With no cloth, will the ply still 'check' or will the epoxy resin keep that in check?

Thanks in advance.

 

[orlandoclippertim]

Re: waterproofing ply with epoxy; with fiberglass cloth or without?

Darren - neat boat by the way ! I was just reading about checking a nite or two. sounds like it might check eventualy without cloth.
If you go to a model shop they have very light glass cloth for model airplanes. I think it is like 1/2 ounce per yard. There is also polyester cloth used to cover airplanes. Cloth stores have a very thin version of that too. It shrinks a little with heat where glass doesn't. The model shop glass is so fine it might give a better finnish (less sanding) than the regular heavy stuff.

Tim

 

[oops!]

Re: waterproofing ply with epoxy; with fiberglass cloth or without?

hi darren.....

great to see you are still at it bud....

use a 6 oz finishing veil. (woven roving)

how have you been keeping?......still at the boat yard?

 

[jigngrub]

Re: waterproofing ply with epoxy; with fiberglass cloth or without?

use a 6 oz finishing veil. (woven roving)

Do this^^^^^

Your plywood won't check with the epoxy, but 1/4" ply isn't strong enough by itself for what you're doing.. The glass mat should strengthen it up nicely though.

How did the Nautolex vinyl and contact cement installation go, got any pics of that?