I drilled and tapped the copper feedthrough and connected the variac and transformer to create a variable low voltage, high amperage source inside the chamber. Now I just need to connect the tungsten wire or boat and it should be good to go.
For the thermal evaporator I’m in need of a feedthrough capable of handling at least 200A while being able to hold a vacuum and be electrically insulated from the aluminum base. For starters I’m attempting to make them from a threaded pipe fitting and a 3/8″ copper rod glued in with JB-weld. I have no idea if this is going to work.
I salvaged a giant transformer from a microwave and wound two turns of 4 gauge wire instead of the secondary. This should theoretically give me a couple hundred amps for thermal evaporation in the future.
I’ve wired up the power supplies for the vacuum gauges and the turbopump. I’m going to avoid sticking my hand in there while anything is plugged in…
Well, the time has come to start putting the turbopump into a proper table. I don’t have thousands of dollars of stainless steel, so a cheap wooden table will do the trick. I also have a glass salad bowl as a simple bell jar. I think it will hold the vacuum- hopefully no explosions :/
The turbomolecular pump and baseplate is assembled and I’m using a stainless steel stock pot as a makeshift chamber. I connected it to the giant Leybold pump for backing and everything looks good!
I’m making a baseplate for my first high vacuum system and holy crap do I need some real machine tools. It took me an hour to get through this 1″ thick aluminum with a tiny drill press and a 4″ hole saw. Then afterwards I had to jerry-rig a sanding drum to smooth it out sufficiently. Safe to say I blew the tolerance and the hole is significantly oversize, but it’ll work.
I picked up an Edwards EXT-255 Turbomolecular Pump off of eBay for an upcoming project. This is the first time I’ve ever seen my meter read 0 microns!
So after some more research I’m starting to believe that the original pump is not enough for this task. Fortunately I happened to impulse purchase a huge Leybold 16cfm rotary pump from a person off Craigslist. It’s not exactly in good condition (It clatters a bit and probably needs a rebuild) but it pulls a good vacuum and it was dirt cheap.
I’ve always been interested in making my own freeze-dried food for camping or emergencies, and I’ve also been interested in the process in general. I picked up a small vapor trap capable of reaching -50C on eBay and a small vacuum pump off Craigslist. I don’t have any machine tools but I managed to drill and tap a 4″ disc of aluminum with a cordless drill and some tenacity. Despite NOT being designed for this, the vapor trap actually seals pretty well against the metal bucket inside (normally they use a glass jar) and reaches an absolute vacuum of about 30 microns.
