What I can use to waterproof that wooden AC tray?

[jhjspecks]

Mike towards the front of you a/c unit is there a lip under it? If not what is going to stop the water from coming forward into the cap? You could remove the a/c, sand the poly for a rough surface, and mix up enough epoxy to pour in and let it set until hard.

[doug hodder]

Mike...I think you could epoxy over the urethane, but you'd want to scuff it with like 80/100 grit to give it some tooth. It'll stick, but the failure might be in how well the urethane sticks to the wood. Maybe try a test piece first. I may have missed it, did you do any stain on it, if so, what did you use? I'd do it, just my opinion. doug

[Laredo]

sounds like the easiest/cheapest solution is three or four more coats of what you've already got on it, Mike. But in a pinch you could line it with one of those heavy clear plastic bags like stores sell ice in.

[ARKPAT]

Marine Grade Epoxy paint. Like mentioned above except without the glass. The more coats the better! Follow the Manufacture recomendation about recoating. Scuff the surface like mentioned above.

Something like this Mike; just a quick google search. You get the idea.


Pat

[madjack]

sounds like the easiest/cheapest solution is three or four more coats of what you've already got on it......................................................

...yep, at this point, that is exactly what i would do...afterall, the spar varnish is supposed to be for such things anyway........

[2bits]

I guess the question is, can you epoxy over spar urethane?
Mike...

I have read that the answer is yes but you need to scuff for adhesion as it is a mechanical bond rather than a chemical bond.

[donmaloney]

I have heard of people using spar varnish on wood boats without epoxy, so it's definitely waterproof enough. Also, spar varnish adheres to epoxy, so why wouldn't it work the other way around?...but, scuff it up as was said before. I would think bar coating would be a good way to go, too. http://www.uscomposites.com/kk121.html It is basically epoxy...you can get it in small batches.