[Public-List] Barrier Coats and Blisters

[Rachel]

I think I agree with the concepts that are expanded upon in the article 
I've linked to.

Basically, it says hydrolysis is going on with any older fiberglass 
boat (pre-vinylester, etc.).  Water is attracted to certain chemicals 
in the resin and gets sucked in through the gelcoat.  Then it makes a 
new fluid with larger molecules (the sweet brown stuff).  On newer 
boats with less-porous gelcoats this causes blisters when the fluid is 
trapped; older boats tend to have more porous gelcoats and this allows 
the hydrolized fluid to escape.  So no blisters on those boats but a 
gradual weakening of the fiberglass as the soluble parts of the resin 
leave the boat.

Now, I'm not saying any of our boats are going to get problematically 
weaker in the near future - it's all done by degrees, and may or may 
not be an issue in the next 40 years.  I don't feel comfortable 
recommending a course of action, as nothing is black-and-white.  I 
think only an owner can decide what to do with an individual boat, 
and/or whether he or she believes in any given theory or barrier 
product.

http://www.zahnisers.com/repair/blister/blister1.htm

Rachel
#221



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