On Mon, 2 May 2011 10:46:03 -0400, "Flying Pig"
wrote:

A friend wrote to me on Facebook. This was my response:

Hi Skip,
Radar wrote: "Was this a result of the fiasco in the Keys and the boat
damaged from the slamming there?"


Hi, Radar,

No, not at all.

We'd done about 800 blisters in our original refit, and this bunch is just
the continuation of the realities of a polyester resin hull. Likely this
won't be the last.

These faults likely would not have been known had my contractor, who was
hired to remove the bottom paint, had not gone all the way to the hull,
removing the tiny barrier coat which remained after all the blisters and the
wreck repair, as there were no blisters evident on haulout (paint still on,
where it was still present, of course).

So, we tackled it, and got an education on blister remediation (no real cure
other than to take the hull down all the way to cloth, removing all the
chop, and re-applying several layers of cloth with vinylester resin, best
for the intermediate layer as it's easier to work than epoxy, and less water
vulnerable than poly, then barrier coat over that).

We're not going to that step, but following LOTS of confirmation, started
with a surveyor on a boat next to ours, which revealed that the best way to
get the water-soluble stuff out of the hull is to wet it thoroughly, and
then pressure wash off to remove that which leaches out, several times,
we've hosed it down, followed by pressure washing, several times for that
purpose alone, as well as more as we've been removing the PoliGlow from the
topsides above the raw stuff, washing it off the hull as well.

We've shown that to be efficacious by the recurrence - and development of
new tiny places - of stuff coming out of the hull. Very little, now that
we've done it a couple of times, and chasing the loose laminate until solid
each time by grinding. Some places are down to the cloth, but most are just
removal of chop which wasn't adequately wet out during layup.

Then, we will go with AdTech fairing epoxy compound, rather than the
laborious layup in the grind voids, based on more research which has been
confirmed by more than one source, to fill and fair the hull. We COULD -
but won't - add some layer of that over the hull overall.

Instead, we'll lay on 30 mils or more of an epoxy based mil-spec barrier
coat, then follow with bottom paint. Our last bottom job lasted 4 years, so
we're hopeful we'll have the same level of success this time, using what
should be better paint than the west stuff we used during our original
refit.

As to AdTech, we only learned of it yesterday, to our great relief, as we
know what it's like to fill the grinds by laborious patch cloth cutting and
wetting and so on with epoxy, which then, too, would require fairing and/or
grinding to level. So, using a wide drywall knife, we'll rough-level the
voids, then long-board sand it fair, covering any low spots after putting on
a reveal compound (purple color, whatever remains after a light sanding is
low), until it's fair. We'll end up with a hull much smoother than it was,
after all the repairs which had been made in the past.

All the research we've done suggests that blisters may continue to be
revealed in the future. However, we'll not address that again, as it will
be below a very substantial substrate, following a very throrough removal of
all the opportunisticly available areas which have hydrolized compound in
them (from the water bath treatments).

Our boat had been peeled before, many years ago, and a (only) very thin
barrier coat put on it. At the time, the method of "drying out" wasn't as
well known; you can leave a boat in an oven for years and not have any
change in the hydrolized compounds, as it takes - counterintuitively - water
to thin them and get them out. Once out, of course, they'll not absorb
water, again.

If the impermeable layer (barrier coat) is thick enough, and impermeable
enough, more water won't enter the substrate, and more blisters won't occur.
Or, at least, that's our story, and we're sticking to it :{))

Thanks for asking.

L8R

Skip



Which makes a far more sensible story then Wilbur's fantasy of
transporting the boat to the Arctic for dehydration :-)

Cheers,

Bruce
(bruceinbangkokatgmaildotcom)