I believe a few pre gas shortage (1974-5?) vessels used Epoxy Resin as a
building material while other used straight polyester. It was advent of
energy crisis that started use of polyester mixed with cheaper styrene to
build boats. Then came that wondrous idea of using encapsulated balsa wood,
followed with encapsulated wood, and lately encapsulated foam. All guaranteed
to suck up water like a sponge and turn a 1ooo pound boat into a 5ooo
pounder... Polystyrene was a poor choice for boatbuilding but is still used.
In addition to some very modern crap. Refineries seem to use boatbuilders as
proving grounds for their mistakes...
One of the known causes of blisters is poor layup procedures in which cloth is
not fully impregnated in resin and bubbles remain in laminate. A second known
cause is poor gelcoat spray and subsequent cloth layup.
I did own a few vessels made with epoxy resin.
My Columbia 22 fixed keel never got a single blister of any size while moored
at Marina Del Rey for 15 years...
Potters can be ordered with 3m moisture resistant gelcoat for a couple hunnerd
bucks more. i did
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Best
SF
In a message dated 99-01-15 18:14:14 EST, you write:
<< Subj: Polyester Hulls and freezing bilges
Date: 99-01-15 18:14:14 EST
From: ryeg@vais.net (Rye Gewalt)
To: wwpotter@tscnet.com (wwpotter@tscnet.com)
Judy B. Wrote:
The Gougeon Bros, manufacturers of the West Epoxy System, state
....Virtually ALL boats are constructed of polyester-resin fiberglass
laminate, not epoxy.
I never gave this much thought because of a bias I got from reading all
of the literature from the Epoxy vendors and really thought that most of
the boats were build with Epoxy. Maybe they are all polyester.
(perhaps that were all the leisure suits went from the '70s). Is
anybody sure what IM uses?
On the effects of standing water.... I think that standing water in the
bilge would be a real problem in areas where there is a freeze thaw
cycle even in small amounts. With the mold release angles in the boat
it probably isn't a problem in areas like the smooth cockpit, but down
below where the ice can get hold of the rough surfaces of the inner hull
I would expect some damage. Probably both at the macro level where the
whole structure is stressed and at the micro level where the ice gets
into the nooks and crannies and loosens things up. One would hope that
the plastic properties of fiberglass would help -- but Ice does some
amazing things.
Of course when it's in a glass with some spirits it OK.....
Regards
Rye Gewalt
Springfield VA
90 HMS 18 with short rig
>>
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