[C320-list] Anti Blister protection

[Bruce Heyman]

Stephane,

On my previous boat, Sabre 30, I did put on seven layers of I2000/2000E
after repairing about 1200 blisters.  Really great stuff and if you follow
the instructions very carefully you will have a great result.  Unfortunately
most yards to not follow some very important steps, I know, as I've watched
them doing it wrong while working on my own boat.  Between each coat you are
striving for a chemical bond and that means that you have to follow the
recoat instructions for what the current temperature is very carefully. If
you miss a window then you have to put up with a mechanical bond which means
you have to sand before you recoat.  You also have to make sure that you
have used the right solvents to remove mold release amongst other things to
make sure you get a good bond (I don't think I've ever seen a yard to this
step).  

For full protection you need about 12-15mils and you only get about 2 mils
per coat.  I sanded most of the last coat off as I wanted a really smooth
bottom for racing.

That said I'm not sure I would recommend you go through the hassle.  The
only Catalina's I've heard of with a blister problem came from the infamous
time period in the 70's when petroleum we a price problem and manufacturers
were experimenting with other formulations.

Besides the hull material there are too main things that drive osmotic
blistering.  One is salt water vs. fresh.  The fresh water molecule is
smaller and hence more likely to get in and be able to cause the blister.
The other factor is temperature.  Boats in a warm climate are much more
likely to blister than boats up in the north.  If you haul your boat
annually and it sits on the hard for several months or more you are even
more likely to not have to worry about it.

Lastly if you do get blisters it is usually no big deal.  Most blisters are
very small and don't even involve the first layer of fiberglass.  They make
your boat a little slower due to the rougher surface but are not structural.


Probably more than what you wanted to know but I don't think you need to do
this unless your gel coat has in some way been compromised.

Bruce
Somerset 671 SoCal

-----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 12:14 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