[C320-list] bottom paint

[Bruce Heyman]

The best time to inspect for blisters is as soon as the boat is pulled from
the water.  Also they will not dry out until you grind them open.  When I'm
inspecting I usually use the hard corner of a stout scraper to go around and
push hard on anything that looks suspect.  If discolored liquid comes out
you have a blister.  Not all blisters are the same.  It is possible to have
blisters in the bottom paint (not too likely), in the barrier coat/gel coat
and in the layup.  Unfortunately just hauling and letting the boat sit
sometimes allows the blister to shrink and then not be detected when you go
to put on the bottom paint.
If you do find some it can take months for them to really dry out.  You have
to grind till you get to good substrate.  The general rule is you should
grind and flair around the blister about ten times the depth.  Then you want
to rinse with fresh water frequently.  As the blister dries chemicals
(salts?) come to the surface and prevent further drying, hence the need for
frequent fresh water rinses.  Was fun when I had to do it through a Chicago
Winter in Winthrop Harbor (not on our Catalina) ....
Bruce
Somerset #671 SoCal

-----Original Message-----
From: c320-list-bounces at lists.catalina320.com
[mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of Chris Descher
Sent: Tuesday, November 17, 2009 2:29 PM
To: C320-List at Catalina320.com
Subject: Re: [C320-list] bottom paint

I left out some details in the initial posting for the sake of brevity, so
here goes.  This is hull number 500.  I bought her about a year ago.  I've
had the boat on a hydro-hoist and power washed the bottom, and to my
untrained eye, there were no noticeable blisters.  This yard will not
repaint until the hull dries out, so the boat may be on stands for months.
They would probably let me do some work myself if I were so inclined.  I
guess that once they start removing the paint, they'll be able to tell what
condition the barrier coat is in.  This is all new to me, and like I said, I
don't have any real options on who can do the work here.

-----Original Message-----
From: c320-list-bounces at lists.catalina320.com
[mailto:c320-list-bounces at lists.catalina320.com]On Behalf Of Jane & Ken
Sent: Tuesday, November 17, 2009 2:54 PM
To: C320-List at Catalina320.com
Subject: Re: [C320-list] bottom paint


Chris,
   I have always been against any sandblasting of the
bottom ----UNLESS----it is to a small blister area that needs removing.  If
you have any blisters, they may need to dry out for several days before any
repairs are done.  The original bottom barrier coat (to prevent blisters)
would be damaged with sandblasting. 
   You did not mention the hull number, but the blister protection method
used by Catalina has changed over the years.  I had three small blisters on
my hull #219 in year number three (1997)---factory warrantee assistance was
more expensive than me doing it myself and no futher problems have occurred.
   Other than the sand blasting part, the yard's approach seems
reasonable--12 years is a long time for the original bottom paint.
Ken  OBUOY  #219

--- On Tue, 11/17/09, Chris Descher <cdescher at cedtulsa.com> wrote:


From: Chris Descher <cdescher at cedtulsa.com>
Subject: [C320-list] bottom paint
To: c320-list at lists.catalina320.com
Date: Tuesday, November 17, 2009, 12:41 PM


I'm about to have the first bottom job done on my 12 year old, freshwater
boat.  Without much in the way of available options on who will do the work
and how it will be done, I really just need to decide whether the estimate
that I've received is reasonable.  The yard will haul it out, sand blast the
bottom, then pressure wash the bottom and hull sides, prime the bottom with
a light coat of bottom paint, then go back with two heavy coats of
anti-fouling bottom paint, and then apply a third coat along the water line.
They use Petit Un-epoxy Plus bottom paint.  Any blisters would be dealt with
separately.

Is there anything about this approach that seems wrong?

Thanks,

Chris Descher