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posted to rec.boats
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Blisters 'n microwaves
wrote:
I may have talked about this idea before but it was inspired when I was
doing blister repairs on a boat and used a heat gun. The heat gun
literally drove water from the hull and it poured out of adjacent
blisters so...........Why waste time heating the glass when you really
want to heat the water and other polar molecules. Enclose the boat in
a cover of aluminized plastic and put a microwave generator inside.
The water and other polar molecules in the gel coat would be driven out
over a few days. Of course you'd have to keep the power level low
enough to not cause arcing near any metal fittings but that should be
easy. You might want to score the gelcoat to facilitate the
evaporation of the water.
Next, you drive thermo-setting resin into the gel coat under pressure
or even slowly setting ultra-low viscosity epoxy. Finally a sealer
coat. No BS gel coat peeling that fails 80 % of the time.
I think the application of too much "heat" can cause more harm than
good, the glass gets moist over time then as you've seen then you
effectively boil the water the expansion (by about 600-800 times by
volume) creates considerable pressure enough to force water out some
distance away.
Clearly there was a path there originally but how much did that excess
pressure open it up or delaminate the layup even more???
It seems to me the best way to remove moisture from osmosis effected
glass is to use an electronic moisture finder (they have them specially
for GRP & most boat surveyors have one in their kit) that way you can
draw the shape of the moisture then limit your drying activities to that
effected area only. Drying causes damage no matter how you do it, by
heat, by grinding, by peeling etc.
As for the microwave idea I guess it's possible however you'd need huge
power to heat a boat hull even a not so big one. A tiny domestic kitchen
microwave which is properly shielded, insulated etc, has the beam
directed precisely at the target, has the target rotate so the tiny beam
can get at all of it over time & they use bulk watts with lots of loss.
I guess another consideration might be any other water in there??? with
a boat, even small amounts if boiled when enclosed, could again generate
huge force & consequent damage??
It's a loopy idea on first pass, but not that much more so than some
others that people have spent huge amounts on. The hull peeling is
another as far as I'm concerned.
K
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