On Tue, 17 Nov 2009 19:37:49 -0500, wrote:

On Tue, 17 Nov 2009 05:26:24 -0800 (PST), ransley
wrote:

On Nov 17, 7:13*am, Jim Elbrecht wrote:
"hr(bob) " wrote:

-snip-

Bondo as used in auto body repair works quite well and is commonly
available. *

Before you do that- take some yellow pine, weigh it, take a chunk of
bondo and weigh it. *Put both in water for a while & see how much more
water the bondo holds than the wood.

Auto-body bondo is not for wood. *Bondo *does* make *a wood repair
product though. *I've never used it- but note that the directions say
"For Rotted Wood Problems, Use After Applying Rotted Wood Stabilizer."

Jim

Bondo doesnt absorbe water its plastic, their 'wood' line is just
bondo, I used it this summer and compared it to regular bondo which is
alot cheaper.
Polyester plastic (which Bondo IS, DOES absorb water. So does Nylon
and some of the Acetates. They will expand when wet, and severe
freeze-thaw cylcles will cause it to disintegrate if wet.
Epoxy, generally, does NOT absorb water.

Well, epoxy absorbs far less water, but it does absorb water. The
other factor is that epoxy usually gets various fillers blended with
it, that may absorb water more easily than the epoxy. The amount of
water absorbed by epoxy can be a factor on the botoom of a boat, but
probably not on a window sash. There is a special epoxy paint used as
a barrier coat to seal fiberglas boat hulls. It has a filler that lays
flat like fish scales to help make the barrier, and requires several
coats to be effective and completely block moisture. unmodified Epoxy
alone will pass moisture.

Even plexiglas has a specification for how much moisture it will
absorb. The number is not ZERO.