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Paul Oman

wrote:

On Jul 7, 6:43 am, Lodewijk Stegman
wrote:

schreef groups.com

Why would it not absorb water? Epoxy is not water proof, water
resistant yes, proof, no.

You make it sound as if epoxy is some sort of grease.

I don't now how you arrive at the conclusion that epoxy is not waterproof,
but I have always lived under the impression that it is not only waterproof
but even fairly vapour-proof. Solvent-free epoxy, that is.

I have worked with it enough to know that it is usually not used in
lab conditions. Weather, sun, stress, and goblins will make even the
most hyped epoxy, let water in. The key however is to engineer with
that in mind. Remember it is much harder for moisture to get out, than
in.

This quality is one of the reasons epoxy is used as an osmosis-barrier on
new polyester boats, for instance.

Hummmm. sounds like a gimick to me. I have not seen a lot of boats
soaked by osmosis through the hull without some kind of disruption to
the laminate itself. But I am more of a wooden boat guy.

It is also the justification of the
techniques the Gougeon brothers have been promoting for ages.

God bless the Gougeon Bros indeed, they have moved the process along
for sure, but they still sell goo!

--
Lodewijk

Hey, I could be wrong here, but my view of this has not let me down
yet. Have a great day and go build a boat!

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

polyester resin (fiberglass resin) is rather porous, which is why many
hulls develop blisters. The simple fix is to coat them / waterproof then
with a layer of epoxy which is much less porous than polyester resin.

is epoxy waterproof. consider your skin. you don't leak when you go
swimming (pls don't pee in the pool!) but technically our skin passes
lots of fluids. FYI

paul oman - progressive epoxy polymers inc