Re: [ATM] incomplete mirror stripping

["Bill Wheaton" <junkwheaton@gmail.com>]

So I did a search for "Green River", not knowing what it was and look
what I found! a nice .ppt presentation about stripping mirrors at Kitt
Peak.  Maybe it would be helpful?

http://www-kpno.kpno.noao.edu/glaspey/KP/Coatings/Conference2001/MirrorStripping/sld001.htm

-Bill

On Tue, May 6, 2008 at 7:00 PM,  <lenses@adelphia.net> wrote:
> Hi Tom,
> Cerium oxide polishing compound with cotton balls (no pressure) your just cleaning the surface.
> Then put it back into the acid, and yes some new green rivers works wonders or just add a bit more hcl.
> DISCLAIMER...I am not a chemist, I learned from someone else who learned from someone else. I wrote most of the stuff down, they just poured it in and it worked.
> Take your time and be careful.
> Pete
>
> ---- Tom Conlin <tomc@cs.uoregon.edu> wrote:
> > Hi Pete
> >
> > Would you elaborate on this "polishing compound"
> > is it a silver polish? cerium oxide? shoe polish?
> >
> > lenses@adelphia.net wrote:
> > > Hi Tom,
> > > Take the mirror and clean it with cotton balls and polishing compound.
> > > DO NOT RUB, just go over the entire mirror with this solution.
> > > Then put it back into the acid (face up) and let it sit.
> > > You can also gently rub on the remaining coated surface with q-tips.
> > > You might have to do this a few times to get the entire coating removed but this is the safe way.
> > > If it doesn't come off stop & send it off to the coater with the to be stripped note.
> > > Or if you want to be daring there is another method that will preserve the surface and should remove the coating spots.
> > > Good luck, let us know how it works.
> > > Pete
> > > lenses@adelphia.net
> > >
>
> > > ---- Tom Conlin <tomc@cs.uoregon.edu> wrote:
> > >> Hi list,
> > >> I recently tried my hand at stripping a couple of mirrors.
> > >>
> > >> The first a home made 8" F8 of un-determined age
> > >> (old yellowish Pyrex?) the coating was translucent where
> > >> it wasn't flaking off.
> > >> Gave it a dilute Hydrochloric /copper sulphate bath and
> > >> the coating fizzed off completely in two or three minutes.
> > >>
> > >> Bolstered with the success I had with my 8" I volunteered to do
> > >> a 6" F8 from Edmond Scientific (circa 1960) for someone else.
> > >> This time the process took much longer and even after a half hour
> > >> some material remains on the mirror.
> > >> I attempted to gently swab an offending spot with a Qtip
> > >> but it remains fast.
> > >>
> > >> The first mirror was not in that great shape, poor figure and scratched
> > >> so I have reground it, but this second one ... is not mine, looks ok
> > >> and I would really rather not mess with it.
> > >>
> > >> So any recommendations on how to remove the last stubborn vestige
> > >> of the old coating?
> > >>
> > >> Should I just leave it and let the coaters blast it off some how?
> > >> or is there a more effective chemical bath I could try.
> > >>
> > >> there is a small Ronchi image (73k) of the stripped mirror here
> > >> http://www.uoregon.edu/~tomc/astronowanabe/ronchi/IMG_2390_crop.jpg
> > >>
> > >> and a short but largeish (33M) video clip here
> > >> http://www.uoregon.edu/~tomc/astronowanabe/ronchi/IMG_2393.AVI
> > >>
> > >> I can put up a direct image of the spots it that would help.
> > >> --
> > >>            ... nice weather     eh          tomc@cs.uoregon.edu
> > >>
> > >> _______________________________________________
> > >> ATM mailing list http://www.atmlist.net/
> >
> > --
> >            ... nice weather     eh          tomc@cs.uoregon.edu
> >
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