Evaporating metal
This is something which we scientists do routinely. Basically it involves boiling metal (aluminium, silver, gold, chromium, whatever - take your pick) using a tungsten or molybdenum element, which is heated electrically. This is done in a vacuum chamber because of the metal's low vapour pressure and also to avoid oxidation of the metal as it heats up.

The metal vapour then recondenses on the desired substrate (forming mirrors on glass and so on) and indeed condenses everywhere else too. But the problem with this technique is that it's a line of sight thing. Parts of the substrate which are closest to the source get coated with a thicker metal layer.

A way round this is to mount the substrate on a rotating base, so it gets more evenly coated. Edwards, the company which makes the ubiquitous (in UK university science departments at least) 306 Vacuum Coater, offers a device called a Rotatilt, which does this very job. But it's quite expensive, and we didn't have one. So my mate and I made our own.

We used the guts of an old car stereo, which had a 12V DC motor and a nice belt drive system, and mounted on this a platform made out of two old CD-ROMs glued together and fixed to the drive using a bespoke (i.e. hand knitted) mounting. A couple of batteries, some wire and a switch and we were all set.

The finished device looked like a bad scale model of the starship Enterprise from Star Trek. So we decided to call it the Scottish Enterprise, as an ironic nod to the local development authority. I wish I had pictures of it, as this story's a bit crap without them, but hey ho.
( K2k6 has a proper job these days, Thu 27 Aug 2009, 11:12, Reply)