On Wed, 27 Apr 2011 21:43:57 -0400, "Flying Pig"
wrote:

We had dinner with a buddy boat tonight. They commented that the barrier
coat they used had a brochure in it which described exactly what we are
doing as particularly important to THEIR system, which they guarantee for
some length of time (years). When I have the actual brochure in my hands
I'll repeat it verbatim - along with the name (Interlux, I think) and
product number - here in a followup. However, at least one manufacturer,
and in particular, one which offers a guarantee, agrees that the only hope
one has for a successful barrier coat is to do exactly what we're doing.

The continued research we've been doing suggests that if the fiberglass
isn't perfect in layup (materials, humidity, application techniques, etc.),
once you START having blisters, you're going to continue to have blisters,
no matter what you do about it.

Actually polyester composites are not waterproof and as the uncured
chemicals are present in all layups, in some amounts, osmosis will
occur in all polyester based laminates, in some degree, in time.

The modern "treatment" is to initially lay up hull with an external
layer of vinylester resin which is more waterproof then polyester and
cheaper then epoxy.

Your "barrier Coat" by the way, is simply epoxy and the important
factor is to apply it in the thickness recommended. Probably two coats
totaling about 12 - 16 mils.


HOWEVER - the best you CAN do, apparently, is, indeed, to wet the hull and
then pressure wash it, several times.

Yesterday we wet it thoroughly. Today, new areas were visible (encouraging
the now-liquid-ized stuff to come to the surface), albeit all still VERY
small. The new cheapo pressure washer was applied to the surface next. Any
blisters with the slightest amount of open area allowed water in under
pressure, further lifting any non-perfectly bound glass, and, further, for
the most part, causing it to depart the skin of the boat as, once the
process started, the light stuff blew off, allowing access to more of it,
and so on.

So....

Not only does it work, but it's going to save me a lot of grinding to get
the same areas removed for "packing" prior to the barrier coat. Those areas
I'd already identified were, of course, the worst (if you can call an area
of less than a dime in size "worst"), and were more prone to opening with
the puny 1600PSI sprayer we have. However, a few more of these treatements,
and I expect we'll have a VERY good remediation of the tiny blisters we
have. Sure is fun to see the hull getting lighter as we wash off that tiny
film of hydrolized compounds which have been making their way to the surface
and darkening it slightly!

L8R

Skip, who MAY get some more pix up some time soon, after I get some of the
PW series yet to be taken in and out of the camera...
Cheers,

Bruce
(bruceinbangkokatgmaildotcom)