From: George Anderson 
To: Russell Jocoy 
CC: ronaldn{at}ptd.net, atm{at}shore.net
Reply-To: George Anderson 


Hi Russ

I have gone for a touch more than full thickness with respect to glass, the
5" mirror is a 1" thick at the edge. The aluminum extrusion that
I bought was not available in less than 1" slabs from the seller. I am
hoping that the additional heatsink mass will make the mirror more stable
than a thin mirror.
A constant temp heater and control circuit would not be too difficult,
however you would then most likely end up with a mirror that was not at
ambiant thus producing other problems.

George Anderson
Montreal Canada

Clear skies and good health

Russell Jocoy wrote:
>
> >From: "Ron Newman" 
> >Reply-To: "Ron Newman" 
> >To: 
> >Subject: Re: ATM polishing aluminum
> >Date: Fri, 14 Mar 2003 07:37:41 -0500
> >
> >
> >Try Tripoli as well as rouge for aluminum. Both work well in vibratory
> >tumblers for polishing aluminum parts, However is it good enough for a
> >experimental mirror surface???
> >
> >Ron Newman
> >www.focuser.com
> >
> >
> > >Rouge should remove the black.
> >
> >
> > >> A question for the metalworking guru's on the list.
> > >> I am currently in the process of polishing (or attempting to) an
> > >> aluminum mirror (it is an experiment/fetish) with cerium oxide.
> > >> The surface is a smoother than with the 10micron grit
when I finished
> > >> grinding, BUT the surface of the aluminum is getting
blacker each time
> >I
> > >> polish. Is this a case of it is always darkest just
before dawn, or
> >does
> > >> cerium oxide react with aluminum? Is there a better polish for
> >aluminum?
> > >>
> > >> George Anderson
> > >> Montreal Canada
> > >>
> > >> Clear skies and good health
> > >>
> > >>
> > >
> > >
> >
> >
> ("atm{at}shore.net")
>
>        George, I have polished aluminum to a mirror finish. You can use many
> products to get to the
> mirror image......, but you will never be able to control the heave and ho
> of the characteristics (sp)
> of this metal.  Telescope mirrors have moved to hard,  and more stable
> materials such as glass.
>      I have experimented with thin aluminun and flexing the center with a
> bolt and a wing nut.
> After alot of work , I was disappointed. If your think glass has a heat
> /cold temperment, figure your
> aluminum curve and watch the circus mirror move with any... temperature
> change.. no control unless
> you rig a constant temp/heater and you are spending way too much time and
> cost. But if you have the
> time.. and can come up with a stable reflection.. more power to you.....and
> let me know of the process.
>      Russ Jocoy...................
> ("atm{at}shore.net")
>
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