Acetic Acid and Aluminum
Steve Scampini (scampini@hpangrt.an.hp.com)
Tue, 11 Apr 95 11:29:16 EDT
Hi Everybody,
As was pointed out in a recent set of postings, I did SUGGEST to think
twice about using silicone with acetic around aluminum. It was also
inferred that I am not a real chemist (I just play one at home sometimes)
...in fact I am not. I am also curious on what a real chemist has to
say about compatibility of aluminum and acetic acid. My simple experiment
of immersing an aluminum strip in clear vinegar for two weeks showed a
definite dulling/pitting of the surface. Was it the alloy? I would
think that the mirror overcoat may prevent or delay the attacking of the
aluminum. I have heard that the natural oxide of aluminum is very tough
and happens very quickly. Any chemists out there?
Also I have seen some traffic regarding setting the secondary to primary
distance on a newt. There is a wonderful shareware program, I think called
"Newt20" that is very useful in playing with various newt geometries.
Also, for the uninitiated (not many in this forum), I would strongly
recommend MEASURING the focal length of your mirror even if it is
etched on the back by the vendor (as mine was) before cutting holes. I
lost about 0.4 inches of precious in travel and I strongly suspect it
was because the mirror was off.
Steve