Re: [ATM] few questions about aluminizing

[Dominic-Luc Webb <dlwebb@canit.se>]

>
> MD> 1. How many micrograms of Aluminum lays on square centimeter ( or inch
> MD> ?)
>
> Typical coating is about 20nm to 50nm thick. I make that about
> 4.6ug/cm^2 to 11.5ug/cm^2 but check the sums for yourself.
>
> --
>
> Best regards,
>   Richard in the UK

Sounds right to me, although, there should be a lot of aluminum that
does not make its way to the mirror, so this is only a measure of what
ends up on the mirror. I would expect considerably more to placed onto
the heating elements in the chamber. I know people have succeeded to
several thin strips of aluminum foil for an 8" mirror, for instance.
You can check my math, but according to Richard's equation, an 8" mirror
would take about 3.6 mg of aluminum. I just took a roughly 2 cm strip
of common grocery store aluminum foil, and this weighed a whopping
400 mg, well in excess of what is needed. In essence, I you are wanting
very small amounts of aluminum. To test your system, you may want to
try some common plate glass. There are some issues about getting an
even distribution, so ideal glass to test should be similar in size
to your mirror.

Dominic-Luc Webb

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