RE: ATM Amatuer vacuum coatings.

["Sam Michael" <samm@idcomm.com>]

Hi Michael.

I did try silvering.  For me it was just too difficult.  I was never able to
get a coating that was worth keeping.

Yes it looked great in some areas but not in other.

I always got SOME blooming and it never buffed well.  At one point, I even
accidently etched the mirror trying to clean it.

I found cleaning to be the most difficult part of Silvering.  I have to
admit that I am not AS careful when I vacuum coat.  The ION source gets rid
of any impurities remaining on the surface.  I clean with Nitric Acid and
Acetone to remove organics and than I clean with alcohol to remove the
acetone.  I am careful not to touch, put into the chamber and let the plasma
clean the rest.

It may take a lot to get a system to coat together, but once everything is
in place, it is easier on a per job basis.

I have tons of the stuff required to silver and will probably try it again
sometime.  But I am sure that I can evaporate Silver more easily than I can
chemically apply it at this point.

Sam.

> -----Original Message-----
> From: owner-atm@shore.net [mailto:owner-atm@shore.net]On Behalf Of
> Michael J. Coslo
> Sent: Thursday, April 08, 1999 12:17 PM
> To: atm@shore.net
> Subject: Re: ATM Amatuer vacuum coatings.
>
>
>
> At 7:33 AM -0700 04/08/1999, Steve Krause wrote:
> >I am interested in seeing what goes into it.  I work at a school district
> >and am planning on getting the kids involved in building telescopes.  I
> >hope to have a grinding workshop occasionally plus grinding a 24" mirror
> >for the school.  If we are going to do a number of mirrors, it might be
> >worth our while!
>
>       You might also be interested in silvering the mirrors. This process
> is easier, much less expensive, and doesn't have quite the learning curve.
> It also involves chemistry, so the kids could get more of a
> multi-disciplinary approach. The silver doesn't last as long as
> an aluminum
> coating, but with proper care (like don't cook eggs around it, and don't
> set it up next to a coal-fired power plant, the results can be very nice.
>
>       - Mike -
>
>