Re: Are Aluminum Mirrors in reach of the ATMs?

[Mike Coslo <mjc5@psu.edu>]

	Alumininum is the holy grail of some mirror makers. It is cheap, easy
to machine, and as far as I can see, just doesn't make a very good
mirror. There have been experiments lately (NASA) with polishing AL with
India ink, which is interesting, because I recall reading about India
ink as polish in an old book somewhere. I believe a link was posted here
with the india ink polishing a day or so ago.

	But there are some big issues with it. There is the grain of the
material. There is also the thermal characteristics which aren't all
that great. Then there is a tarnish issue. Assuming you are trying to
have just an aluminum surface on the mirror, you will need to
polish/refigure every so often.

	IIRC, some people have made the basic mirror, then plated it with a
harder metal, then figured, then applied an aluminum overcoat. Seems
like too much trouble for a mirror with not-so-good thermal characteristics.

	- Mike -

Malcolm wrote:
> 
> Hi Everyone,
> 
> Is there anyone out there thinking about making an all Aluminum mirror?
> 
> I'm just a little confused if you would or could (how) parabolize.
> 
> My first thought would be that its almost identical to using glass, but the
> final figuring would be a little more involved
> 
> Regards