Boat Building Forum

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Varnish vs. Polyester Resin
By:Doyle
Date: 4/26/2000, 1:09 pm

A month or so ago there was a post about using polyester resin rather than varnish. I had two people who understand fiberglass tell me that polyester resin would be a good alternative to varnish. It was supposed to be easier to apply than varnish, look like varnish, and last longer than varnish.

I gave it a shot, I wouldn't do it again.

The resin was easy to apply. Roll it on just like epoxy, it doesn't drip much at all. Resin/catalyst without wax applied never really hardens, if you add wax, you have to sand between coats. You must apply the resin with the temp. over 70 degrees. Because the resin coat is so thin, it takes days to set up. While it is setting up, all sorts of things can stick to your boat. With the wax added, the final coat sets up, but you can't sand it with anyhting other than wet/dry sand paper or the the fibergalss turns to goo.

I had a some bubbles/ripples develope after each coat. The bubbles were never in the same place twice, but they were all on two panels of my multi-chine Coho. I still haven't figured that out.

With my scraper and wet/dry paper I have the boat looking pretty good. I does have a glossy sheen like multiple coats of varnish. I was able to clean up the bubble areas pretty good. I am hoping that over the summer the fiberglass will cure more and I can go back and clean up a few spots next winter.

In hindsight, I didn't think the whole process through. The nice part about varnish is you can always sand it off if you have a problem. Once you start with fiberglass resin, you are committed.

I hope to launch the boat this weekend. I can't wait to start boat #2.

I apreciate all the good ideas I have picked up on this board.