T-304 stainless is what you want to use. It's safe for food and is
bendable. And weldable, although you could come up with a design that
screwed to an aluminum interface plate. Coat the exposed aluminum with
slow (not 5-minute) epoxy and use epoxy also in your bond area instead
of thermal paste. Just make sure the surfaces mate really well so your
epoxy layer is thin. And even though your aluminum-stainless interface
is screwed together, put epoxy in that interface too.

Do not get epoxy on the little thermopiles in the cooler. Epoxy injures
them while it cures. Fill the cooler and its edges with high grade
silicone caulk.

Since it doesn't have the desirable thermal properties of aluminum or
copper you will need to keep a thick cross dimensional aspect. I'd say
..25 inch x 1 inch is a good compromise between performance and being
able to bend it without damaging it. Two or four "legs" reaching into
your liquid should do the job.

You can get T-304 in flat bar in any major area or even order small
amounts from online metal vendors.

If you need any advice about the proper way to power a thermoelectric
cooler, just ask, I have lots of experience.

Best regards,

Bob

On Thu, Feb 21, 2013, at 02:18 PM, veegee wrote:
> Hi all,
>=20
> I will be using a thermoelectric element to keep the drink in my 1L
> water jug cool. The fluid can be anything including water, iced tea,
> carbonated drinks, etc. The water jug itself looks similar to this:
>=20
> http://i01.i.aliimg.com/photo/v0/358876273/High_quality_glass_jug_with_li=
d_water.jpg
>=20
> The cooling mechanism is as follows: a thermoelectric cooler will sit on
> the top of the jug, in place of the cap, with the hot side facing up. A
> heat sink (probaby aluminum, doesn't really matter) and fan will be
> attached to the hot side.
>=20
> On the cool side, some kind of heat sink will extend into the jug and
> will be in direct contact with the fluid which it will cool. My question
> is: what type of heat sink is safe for this purpose?
>=20
> Copper is used in plumbing, so I initially thought of a solid copper CPU
> heat sink of some sort. I could also potentially solder or weld a bunch
> of long, thin copper pipes to a copper plate. The pipes would extend
> into the jug to cool the fluid. Doesn't need to be very efficient, just
> enough to *keep* a drink cool, as opposed to cooling something quickly.
> I'm not sure how suitable copper is when in contact with acidic drinks
> though.
>=20
> I have a bunch of aluminum heat sinks, but I'm not sure how safe they
> are for this purpose. I'm concerned with too much metal leeching into
> the fluid. Apparently, drink cans are made of aluminum, and can contain
> many different types of fluids including acidic beverages. But I'm still
> not sure...
>=20
> Ceramic sounds pretty safe, but I'm not sure what to look for here.
>=20
> Any tips?


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