>On Thu, 13 Oct 1994, Thom Fitzpatrick wrote:
>
>Sorry to disagree, Thom, but Gelcoat is a two part pigmented epoxy resin
>that is used as the exterior coat on fiberglass boats.  It is very hard,
>and as a consequence, a bit brittle. Fiberglass is, however the same resin
>bulked up and reinforced with glass fibers, so bonding between the two

Uh, but I was still right - it is a coating.  I looked into using it to
repair a surfboard and I was steered away from it because of the need
for anaerobic curing, amongs other reasons.  Technically, fiberglass is
the woven mat or roving, consisting of spun fibers, used to form the part, 
to which the resin is applied to make it hard.  The gelcoat helps seal
the final layer of resin.   Pigments may also be added to this resin, but
are completely optional.  The higher the quality the resin, too, the 
clearer it will be, but the really clear resins don't seem to have the
strength of the "industrial" resins.

MekPeroxide is used as the catalyst, and MekKetone can be used as a thinner;
I don't know the components of gelcoat.

Speaking from my surboard-shaping experience, one would use a laminating
resin to put the layers of mat (or roving) together.  Laminating resin
does not contain any surfacing waxes which "cure" the finish.  A sanding
resin can then be applied, which some people will use a very hot coat of 
laminating resin with a small amount of wax.  Or you can go straight to
a hot coat of finishing resin, and sand it and buf it to get a nice shine.

In this instance, the gelcoat would be used instead of the finishing resin.
In either case, we want someting that will seal up the top and keep the
glass fibers from seeking liberty in the winds of life.  Whether or not
it would actually be practical in this case is another story.

There are also pre-formulated marine resins, pre-pigmented and all, that 
can be painted on after the addition of catalyst, and I've also seen some
that don't need a catalyst, but I haven't tried any.

Martha, are you getting all this?

Thom
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