Interesting
residue from a Sharpie or Magic Marker on a mirror
that I cannot remove before aluminizing it!
Here's how it
happened: David C is making a 12.5" mirror and based
on ronchi and foucault/couder zonal readings, it looks
pretty good. We tried using a wire test, and to do so,
I used a Magic Marker to draw a chord or diameter and
marked some points on it. (Saw professionals at NuTek
near Baltimore do the same thing, thought it couldn't
hurt.
We
then tried to do star testing. However, trying to do
that outside when uncoated was a nightmare. So I
figured it would be asier if I did a quick-and-dirty
coating in our Consolidated Electrodynamics vacuum
chamber and alumizer, vintage mid-1960s. Literally
"quick and dirty" because I didn't even wash it off.
The aluminum stuck just fine, but you could see our
fingerprints and the Sharpie line through the
aluminum. Did some more testing.
Yesterday,
we decided to do a real coating. ?So we got out the
'green river' and the paper towels and stood outside
in the snow and cold and watched Venus and Mars do
their slow evening dance whille the aluminum came off,
which it did.
Then we took the
mirror into the CCCC kitchen to clean off anything
remaining (and warm up) using our regular agents:
Alconox powder and powdered USP calcium carbonate
(separately) with water and cotton balls.
Guess
what?
We could still
see, clearly, where I had drawn the line with the
permanent marker, despite repeated washings and
scrubbings.
We even tried
laquer thinner. ?No change. We haven't tried acetone,
because we were out, and intend to do so, but at this
point I'm not sure it will work either... Methyl Ethyl
Ketone? I sure hope it doesn't need polishing again,
because figuring a 12.5" mirror is a WHOLE lot of
work.
Weird.
Anybody
have comments or ideas?
?
Guy
Brandenburg, Washington, DC?
guysmathastro.wordpress.com
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