From: "Dale Campbell" 
To: ,, 
Reply-To: "Dale Campbell" 


One of the first things I learned in college chemistry was don't put
potassium hydroxide (caustic lye) or sodium hydroxide in glass bottles
because it will etch the glass.  The problem is compounded in glass bottles
with ground glass stoppers, as the hydroxide will etch stopper and bottle
together.  The bottle cannot be opened and must be discarded (Yes Richard,
this is something I saw with my own eyes, not received wisdom!  And I, of
course, didn't do it myself. That's my story and I'm sticking to it).

This comes up every once in a while on the list, but that might be a good
thing.  I don't know how long it would take a hydroxide solution to etch an
optical surface enough to cause an optical effect.   I know others have
used
hydroxide to remove coatings and said there was no effect on figure.
However, I assume roughness would be the more likely result, and no one has
ever said they looked at roughness after using hydroxide.  I consider that
an open question. Anyone have data?

With mirror surfaces highly polished and figured to the nanometer, I would
just be more comfortable using a safer method of removing a coating.  Ken's
other two suggestions (ferric chloride or just let it come off in figuring)
are fine.



Dale Campbell
Senior Research Scientist
Advion BioSciences
Ithaca, NY 14850

www.advion.com
N 42.48 W -76.49

>>> "Ken Hunter"  Monday, March
10, 2003 >>>


OR...

You can try a weak solution of Caustic Lye (Drano)


Ken Hunter

. is there a way to do it myself?

steve

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