Subject: Re: [baidarka] Glues
From: Gerald Maroske (gmaroske@arcor.de)
Date: Tue May 25 2004 - 15:39:13 EDT
Hi all,
I have no info concerning the allergic potential of epoxy hardeners, but
it
should not be messed up with polyester resin, where the hardener is much
more
toxic than the resin. In fact, epoxy resin is considered to be much more
toxic
than the epoxy hardeners, so be careful especially with spilled resin
etc.
Resorcinol glues I know of require tight and accurate joints and have
little
gap-glueing strength. Epoxies, well tuned, can fill larger gaps in
comparison
to resorcinol glues without significant strength loss of the glued
joint.
In addition, resorcinol needs clamping with high pressures. This is
summarized
from "Building classic small craft" by J. Gardner. His bottom line is,
anything
recorcinol can do is done better by epoxy. He states, aside form the
gap-filling properties, curing temperatures can be lower with epoxies
and the
dark colour with stain som woods badly if you plan to varnish.
My own experience is limited to only one brand of resocinol glue, but I
still
use it for laminated paddles.
The "Woodworking Handbook" recoomends resorcinol for laminating timbers
or
assembly joints which have to withstand severe service conditions. But,
according to Gardner, the US Plywood Corp. asks for a glue line not
thicker
than 0.005 inch, which is not that much.
Gerald
Michael Daly wrote:
> On 18 May 2004 at 9:20, stlowe@hotmail.com wrote:
>
> > I'm surprised to hear doubts about the use of epoxy as a boatbuilding
> > glue
>
> I've never heard such - epoxy is the boatbuilder's glue of choice.
>
> > all epoxies are very toxic
>
> That's a bit of a stretch. Epoxies are certainly not nice and should
> be handled with care prior to curing. The hardeners in particular
> are hyperallergenic - they can easily lead to allergies. The best
> epoxies are tolerable to breath (though it's definitely not
> recommended). Keep it off your skin and make sure you've got lots of
> fresh air and/or a VOC filtered mask.
>
> Once cured, most epoxies are quite safe.
>
> Mike
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