There are epoxies specifically for thermoelectric coolers and heatsinks,
and I spec them in products, but for my own personal projects I don't
bother. As long as you use a good brand of very slow epoxy it works
quite well. And for the thermal interface between metals or metal-to-TEC
you absolutely should use an epoxy.

At hardware stores there are usually two or three types of epoxy. On the
instructions look for the cure time and get the slowest. If the surfaces
were polished, hit them with 320-400 grit sandpaper. Prep the surfaces
with something really volatile that is not alcohol.

Another type of epoxy that works well is "J-B Weld" but it's sometimes
hard to get a thin enough layer. That stuff is extremely resistant to
chemicals, and sunlight, too.

I think thermal epoxy and J-B Weld both have fillers in them that make
them able to handle the expansion/contraction.

Friendly regards,

Bob

On Thu, Feb 21, 2013, at 04:15 PM, IVP wrote:
> > use epoxy
>=20
> Bob, is epoxy flexible enough in an application with thermal
> movement ? Is there a flexible epoxy available ?
>=20
> Although it's low, I might be worried about the difference in
> the thermal expansions shearing the epoxy or pulling it off one
> face
>=20
> My thought would be a flexible adhesive, such as neutral-cure
> silicone or co-polymer, with as much of a 3D joint as possible,
> including very rough scouring of the surfaces and mechanical
> fixing
>=20
> The reason I bring it up is my experience with fish ponds and
> aquariums, using a variety of materials - wood, glass, plastic
> and metals - exposed to a range of pH and weather conditions.
> Epoxy would be my least-preferred adhesive/sealer for that

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