[C320-list] Anti Blister protection

[Bruce Heyman]

 Vinylester is much more resistant but still susceptible to blisters.  Fact
is that water will eventually find it's way into a hull that spends this
much time in the water.  They key to avoiding blisters is to lay up the hull
in such a way that there are no voids and to that all the reagents are
thoroughly mixed.
If the water gets into an area that was not fully wetted out (vacuum bagging
goes a long way to eliminate these areas) and there are any reagents that
were not fully mixed and hence did not fully cure then you will get the
formation of the acid.  The acid will then begin breaking down the fiber
glass and binding material that it is in contact with.  Because the
molecules in the acidic solution are more complex than straight H2O they are
too large to go back out the way they came in.
If you do find some blisters at haul out you should pop them with the corner
of your paint scraper in the fall so that they have the winter to dry out.
Unfortunately as the area dries, salts come to the surface which prevents
further drying so you need to rinse the hull with water every couple of days
to keep the drying process going on.
Once you punctured the blister the gel coat is no longer going to provide a
good barrier coat and you should do something, at least in the area of the
blister, to protect the underlying glass.
Bruce
Somerset 671 SoCal

-----Original Message-----
From: c320-list-bounces at catalina320.com
[mailto:c320-list-bounces at catalina320.com] On Behalf Of Allan Field
Sent: Thursday, January 18, 2007 3:17 AM
To: 'C320-List'
Subject: Re: [C320-list] Anti Blister protection

Ken - The one thing I am unsure of was when Catalina switched to vinylester
but I believe that all C-320's are vinylester.  Perhaps someone else knows
for sure.  But you are right, boats made in the 70's and 80's in particular
had blister issues.  My old boat was a 1981 and like I said before, required
a complete peel, 6-months for the hull to dry out, then a new lay-up. -
Allan

-----Original Message-----
From: c320-list-bounces at catalina320.com
[mailto:c320-list-bounces at catalina320.com] On Behalf Of K L
Sent: Thursday, January 18, 2007 1:38 AM
To: c320-list at catalina320.com
Subject: Re: [C320-list] Anti Blister protection

I was in a sailboat partnership in the 1990s with a 1985 catalina 30. When 
we sold her in 1999 she had thousands of blisters. Ok, maybe that was a 
slight exaggeration but she did have the pox bad. Real bad.

Ken Danko
802, Grace



>From: "Allan Field" <Allan.Field at comcast.net>
>Reply-To: Allan.Field at comcast.net, C320-List <c320-list at catalina320.com>
>To: "'C320-List'" <c320-list at catalina320.com>
>Subject: Re: [C320-list] Anti Blister protection
>Date: Wed, 17 Jan 2007 21:13:09 -0500
>
>Stephane - Blisters, as I understand them, are caused by the inevitable
>migration (think osmosis) of water into the hull where the water reacts 
>with
>the resins (polyester?) that used to be used in layup.  This reaction
>created an acid which then ate its way back out.   Once you actually see a
>blister, the internal damage has been done.  That said, there is no case on
>record of a boat sinking due to blisters, at least as of about 6-7 years
>ago.
>
>The hull on the Catalina is laid up with vinylester resin from rubrail to
>rubrail; most production boats now use vinylester from waterline to
>waterline so kudos to Catalina.  Water migrating into the hull does not
>react with vinylester resin to create an acid thus supposedly no blisters.
>According to Gerry Douglas, Catalina designer, there have been a very few
>cases of very minor blistering with Catalina's but none in the past few
>years.  That said, I am not sure why Catalina's hull warranty is only 5
>years and pro-rated per year at that.  Regardless, after having gone 
>through
>an 8K complete peel down and re-layup on my previous boat, I am 
>particularly
>sensitive to this issue.  At the end of the day, I have decided to trust
>Gerry and not go through the time and expense of doing a barrier coat.
>Seems to me it would be akin to wearing a belt with suspenders.  Just my
>thoughts...
>
>According to informed but anonymous sources, the only boat that Catalina
>ever made with non-vinylester layup was sold to a woman in the San 
>Francisco
>Bay area who bought it for her boy-toy.  But this may just be another urban
>legend...
>
>Allan S. Field
>Sea Shadow - #808
>Columbia, MD
>
>-----Original Message-----
>From: c320-list-bounces at catalina320.com
>[mailto:c320-list-bounces at catalina320.com] On Behalf Of Stephane Rousseau
>Sent: Wednesday, January 17, 2007 3:14 PM
>To: c320-list at catalina320.com
>Subject: [C320-list] Anti Blister protection
>
>Hello,
>
>I have a Catalina 320 1998, this year, I have remove all the antifouling on
>the bottom. It can be a good time to make an antiblister protection
>(Interprotec). I know that some boats and years need it. Does Catalina320
>boat need this protection to be added?
>
>Thank
>
>Stephane
>
>
>

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