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On Wednesday, March 8, 2017 at 9:51:05 PM UTC-5, rangerssuck wrote:
On Wednesday, March 8, 2017 at 9:29:14 PM UTC-5, Jim Wilkins wrote:
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On Wednesday, March 8, 2017 at 2:38:15 PM UTC-5, rangerssuck
wrote:
I just pulled a piece of aluminum out of my scrap stock bucket
that
was particularly filthy. Dried up oil & dirt.

Sitting on my desk is a bottle of stuff that I mixed up to
unclog an
inkjet printer. I figured what the hell, it's better than
nothing,
and gave it a try. It worked great, and I'm thinking this could
be
my new go-to every day cleaner. It's super cheap to make:

1 part household ammonia
1 part 91% isopropyl alcohol
3 parts distilled water

Just thought I'd share.

Just don't let the ammonia sit on aluminum for long periods of
time.
Rinse it off. It's alkaline and it will eat aluminum.

--
Ed Huntress
=========
https://en.wikipedia.org/wiki/Season_cracking

-jsw

I don't think the ammonia is sitting on the AL long enough to do any
damage - it's not discoloring, and just wiping it off leaves no
discernible odor. I suppose a quick water rinse would be easy
enough.

Season cracking, huh. That just shows what happens when you let your
lazy soldiers take days off for inclement weather. Ties in well with
Iggy's mail problem, though. Neither rain nor sleet...

The effect of various dilutions of ammonia on different grades of
aluminum is very complex. At some solutions, it creates a layer of
aluminum oxide that effectively passivates the aluminum. At different
concentrations, it works right past the porosity in the oxide and
atacks the parent metal.

Here's the weird thing: Low concentrations, like we have with
household ammonia, can cause more trouble than high ones.

Don't ask me why. I don't do chemistry. I just spent years filling my
head full of practical engineering data on materials used in
metalworking. d8-)

--
Ed Huntress

==================

This is the general reason why ammonia promotes the dissolution of
metals more than it's relatively mild alkalinity would suggest.
http://www.science.uwaterloo.ca/~cch...3/complex.html
The ammonia molecule is asymmetrical and carries a polar charge that
makes it stick to metal ions.

We learned the principles of chemistry but not all the details, so
after graduation we would be prepared to understand the explanations
which may be proprietary information.

-jsw