Harold,
I will check at the auto hobby shop on base, they may have a bead blaster.
In absence of getting my hands on any sodium hydroxide, is there any household
item that I may use to acid etch it like maybe some kind of draino product
designed to free clogged drains? If they don't have a bead blaster, I may just
use emory cloth by hand on the fins. Definitely won't paint it.
I am going to use a combination of this aluminum heat sink and also a
copper heat spreader that I have coming off ebay and liquid cooling, yes this
is going to be overkill but I don't see how that is going to hurt anything.
I am emailing some stateside machine shops about getting some "gun drilling"
done for the liquid cooling holes (1/4inch across a 5 inch width). I read that
commercially, they expand the 1/4inch tubes inside the gun drilled holes but
that isn't an option because I don't have a clue how to "expand" 1/4inch OD
copper brake line inside of a gun drilled 1/4inch hole. I was thinking to take
a drill bit just a little larger in diameter after I get the gun drilling done
and push the copper brake tubing in maybe 1/2" and then solder the tube in
place. I am concerned that once I heat up the heat spreader with a torch
momentarily to get the solder to bond the brake tubing to the gun drilled hole
then I will warp it. If I warp it, this will open up a can of worms when
trying to get a good surface to attach the heatsunk devices and the aluminum
heat sink as well. Any ideas on how to attach the brake line to the heat
spreader? The heat spreader is 3/8" thick and the OD of the
hole will be approximately 1/4" I've never worked with copper (C110) like this
and another person even said the copper can get gummy when drilling it?
Respectfully,
Mike Kendall
Harold Mandel <ka1xo@juno.com> wrote:
Dear Mike,
When finishing drilling the holes on aluminum heat sinks
I bring them to a machine shop where they are either
bead blasted or sand blasted to get rid of the polished surface,
breaking up the surface RMS (finish).
This enables the wind crossing their surfaces to be disturbed more
(albeit on a microscopic level) and thereby transferring more surface
heat to the wind from the aluminum.
The color Flat Black will absorb IR radiation more than shiny metal
because of the diminishment of reflectivity of wavicle EM radiation,
but will not emit EM radiation as efficiently.
Remember, the more surface area, even at the microfinish level, then
more area to transfer heat as a radiator. Finishing the surface thus
prepared
with any coating such as varnish or lacquer defeats the purpose entirely.
The best
finish for scuffed aluminum radiators is pickling in caustic soda (Sodium
Hydroxide).
Respectfully,
Harold Mandel
W4HBM
-----Original Message-----
From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
Behalf Of mike kendall
Sent: Saturday, July 22, 2006 9:47 AM
To: amps@contesting.com
Subject: [Amps] making aluminum heat sinks black
Hello,
Just recieved a large 1foot long aluminum heat sink off ebay. I read
that it will work much more efficiently if painted black on one web page.
Any suggestions on the right kind of paint that will stick and not flake off
and if it is worth making it black instead of leaving it as bare aluminum?
73,
Mike Kendall
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