Peel ply on non waxed vinylester
 

I am planning on sealing the fuel tank bulkhead plywood on the 25 with vinylester, thinned with styrene monomer. After that I will glass it and tab it into the hull better, but it needs to wait a week or so, but I want the moisture resistance until then. My thought is to use a layer of peel ply, but I wasn't sure about peel ply over a thin layer of poly or vinylester resin if it is unwaxed, as the top layer doesn't fully cure? Any thoughts?

Thoughts that don't involve using epoxy, that is.

Finish w waxed gelcoat?

Sorry, I was worried that the layer under the peel ply might be weird as it is so thin and so near the surface that after the peel ply removal it might have a layer of cure inhibited vinylester.

I haven't used vinylester resin (yet), but I have used peel ply on polyester resin. When the peel ply is wet out fully, there is no cure inhibited layer underneath.

As I understand it, the reason the surface of a polyester layup doesn't cure is that the MEKP, or some other component of the resin, evaporates out of the surface before the resin can harden. Presumably, the same applies to vinylester. The result is the sticky surface you get with unwaxed resin. The reason wax is added to resin or gelcoat is that, as the resin kicks, the wax is forced to the surface where it forms a barrier that keeps the good stuff from evaporating out. Peel ply can serve the same purpose and has the added advantage of leaving behind a surface with excellent tooth for a secondary bond.

For peel ply to work, you have to have enough resin to saturate it. I don't know if you'll get that with a thinned resin alone. If you weren't planning to add a layer of glass to the initial layup, I don't know if it will work. Why not do the penetrating resin and layup all at the same time? Working wet on wet is the best approach where practical.

And speaking as someone who has done layups in the tight quarters you're talking about, I would make sure you have good forced air ventilation in the bilge while you're working with styrene based products.

Dave

Blue Heron-

Thanks for the insight. I did a few layers of unwaxed, but made a mess of some biax- it stretched/ relaxed in the resin longer than I wanted and made a mess of the compound corners where the stringers and bulkhead meet. So I chickened out and finished with a waxed layer. It is a bear reaching in there from topsides thru a 10x13" opening. I will grind a bit tomorrow and apply small patches/tabs with more waxed resin and call it good. If I feel daring, I will properly skin the bulkhead too. It is mostly resin soaked now. But at least I have some 1708 over the old thru hole/for a raw water intake patch that was filled with mat.

I used a new respirator, and it worked well, but the styrene stings my eyes when I have my head in there. I found out that unwaxed resin is nice in that you can wash it out of your hair with acetone. :)

Nice, indeed. Next time you find yourself in that situation, try these:

http://www.homedepot.com/p/Trimaco-S...4#.UZj6GEqU-KI

http://shop.advanceautoparts.com/web...earchTerm=gojo

Dave