From: "Russell Jocoy" 
To: georgea{at}cam.org
Cc: ronaldn{at}ptd.net, atm{at}shore.net
Reply-To: "Russell Jocoy" 






>From: George Anderson 
>To: Russell Jocoy 
>CC: ronaldn{at}ptd.net, atm{at}shore.net
>Subject: Re: ATM polishing aluminum
>Date: Fri, 14 Mar 2003 23:50:20 -0500
>
>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")
> >
> > _________________________________________________________________
> > Protect your PC - get McAfee.com VirusScan Online
> > http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963





("atm{at}shore.net")

George,  The aluminum I worked with was only 3/16" thick. You say you
have a 1" thick piece.
If this is the case the flex and thermal problems will be way less than
what I had. What is the
diameter of this extrusion?

Russ Jocoy
("atm{at}shore.net")

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