If you just wanted a little mirror
I could make you one. But 50cm is a bit big to fit in the evaporators that we have here.

I should explain - metallisation of mirrors is commonly done by evaporation of the reflective metal onto the glass. This is done by placing it in a vacuum chamber, pumping it down to high vacuum, and heating the desired metal (usually aluminium) to high temperature using an electric current passed through the vessel holding it, called a boat.

The metal melts and evaporates and because there's no air, it doesn't oxidise, but condenses on all the cold surfaces (including your piece of glass) in the chamber. When you vent the chamber and remove the glass, it's nicely coated with metal and is very reflective.

A little lacquer on the metal surface to stop it from being damaged, and voila, one mirror. Frame as required.

Unfortunately I'd struggle to get anything bigger than about 150mm diameter in the evaporators here.
( K2k6 has a proper job these days, Fri 5 Sep 2008, 13:53, Reply)