I'm in the middle of building my DIY chiller. It is a 6500BTU window unit that I removed the evaporator and have replaced it with an equivilant length/size (about 20foot) titanium coil that is housed in a 6" dia PVC pipe. I'm going to Granger today to pick up an thermostatic expansion valve (rated for a 1/4-1HP range) to replace the orifice expansion tube that came in the window unit.
The problem I'm having is "where do I get all the threaded fittings, seals, etc. that are used in AC systems?"