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Message Text |
airmorse
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Remember wood breathes. When the air warms up wood exhales because the wood is getting warmer (bubbles). When the air cools wood cools and inhales (sucks in varnish or epoxy).
Good luck.
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tumblehome
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quote Moonman: "Yes, a cooling temp is best. This can be demonstarted easily by doing a test panel and placing a light bulb a couple feet away. You will see bubbles form just in that spot. You'll notice the inside is worse than outside because air could escape through the inner hull when the outside was done. Another option is to precoat the inside with a thin layer of epoxy before coating. Lots of info on this topic can be found on the bear mountain boats building forum.
Best overall approach is to glass the boat with slightly warmed epoxy in a a room with a dropping temp.
Moonman."
I agree with everything except adding the pre-coat layer. This adds weight to the boat and does not eliminate outgassing.Just let the work space cool slightly as you go to eliminate the problem.
Tom
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Moonman
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Yes, a cooling temp is best. This can be demonstarted easily by doing a test panel and placing a light bulb a couple feet away. You will see bubbles form just in that spot. You'll notice the inside is worse than outside because air could escape through the inner hull when the outside was done. Another option is to precoat the inside with a thin layer of epoxy before coating. Lots of info on this topic can be found on the bear mountain boats building forum.
Best overall approach is to glass the boat with slightly warmed epoxy in a a room with a dropping temp.
Moonman.
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tumblehome
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The air bubbles issue is called outgassing. Your wood has to be warm and then cool as you glass the inside. It's too late to fix this but you need to pop the bubbles as they form and then fill in the craters with dabs of epoxy after you're done glassing. If the wood goes from, say, 80' to 65' you would have no bubbles whatsoever. If you reverse those numbers, you end up with a thousand bubbles.
-T
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jdevries
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Interesting. I started around 10am and finished about noon, so the air temp was gradually getting warmer. Do you think it was the air temp rising or perhaps the heat created by the epoxy curing?
JD
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jdevries
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AARGH!! Glassing the interior and kept getting a bunch of tiny air bubbles coming up, especially but not limited to the staple holes. Anyone else get this? After I was done I would have to come back every 15 minutes or so and brush them out.
JD
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