PETER KEATING wrote:

Thanks Richard, I'll have a look at it this weekend. Regards. Peter
"Rich Hampel" wrote in message
...
A small population of Pinhead sized blisters are usually NEVER a
problem.
Osmotic blistering that occurs in the gelcoat layer or the
non-structural matting layer underneath the gelcoat are simply
"cosmetic". Only when the osmotic blistering begins to penetrate into
the structural layers of the laminate (roving or cloth) would one then
prudently consider a total restoration 'bottom-job'.

They will NEVER go away as what you are looking at is the cosmetic
surface resin has begun (just a teeny bit) to degrade - analagous to
rust in steel and iron.

Your alternatives a
1. open the blisters by grinding, etc. and simply fill and fair the
crater with thickened epoxy.
2. Let the boat dry out a bit and have a moisture analysis performed.
If the analysis moiisture indicates a high % of water absorbed into the
fiberglass, then consider to remove the matting layer and gelcoat (by
'peeling", and recoat with multicoats of epoxy barrier coats, etc. If
high moisture is found then consider to have a sample bored from the
hull and send it to an analysis laboratory to analyse for hydrolysis
and other forms of degradation - dont simply commit to the backbreaking
and super expensive job of rebuilding the bottom.

Simple answer: if you only have pinhead blisters, simply open them,
wash them out, fair in epoxy, etc.

If you applied a barrier coat 14 years ago, the recommended 'thickness'
of such barrier coats in recent years has essentially doubled. If you
didnt apply barrier coat and only have a few blisters in the
gelcoat.... wait until next season and just 'fill and fair' those that
you see.

--------------

I would agree. They will not sink your boat. Pop and fill (if you don't get to
them this spring, another season will not make things much worse). You might
roll on a coat of epoxy paint prior to your bottom paint - sounds like this will
need doing within the next few years or sooner.

paul oman
progressive epoxy polymers