[Elecraft] OT aluminum oxide
Rick Dettinger
k7mw78 at gmail.com
Tue Oct 19 16:34:09 EDT 2010
The lye definitely does eat away the pure aluminum, as I learned in my
miss spent youth! The fireballs were impressive, also, and we were
darn lucky. I think you would need to eat through the good metal just
to get to the oxide, which is on the inside. Heat would probably be
the best bet, and not from burning (exploding) hydrogen. The aluminum
we used for our "experiments" was obtained from old TV antennas in the
dumpster behind the local TV repair store. This was also the source
for our antenna wire. Old bundles of 300 ohm twin lead. We thought
it needed to be bare, since that was what it said in the handbook, so
we burnt the insulation off. What a mess!
73,
Rick Dettinger K7MW
> One possible solution would be to soak the "stuck" joints a solution
> of sodium hydroxide (lye, as in drain cleaner). There's a web site
> that discusses the chemical reaction and the ability of lye to
> dissolve existing layers of aluminum oxide. See:
>
> http://www2.uni-siegen.de/~pci/versuche/english/v44-10.html
>
> The site says, in part:
>
> A layer of aluminum oxide previously formed by passive corrosion is
> dissolved by the addition of sodium hydroxide. For this reason, the
> reaction takes place at the beginning relatively slowly:
>
> Al2O3 + 2 NaOH + 3 H2O ––––> 2 Na(+) + 2 [Al(OH)4](-)
>
> I have never tried this myself, so I would want to test it on some
> scrap aluminum or a no-longer-used antenna, to be sure the lye
> doesn't eat away the pure metal as well as the aluminum oxide.
>
> But it might be worth a try. Use protective goggles and gloves, etc.
> any time you're working with lye.
>
> Lew K6LMP
>
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