If you can't find one locally, you may want to check ebay. They had some good prices on used ones when I looked recently.
I have been tempted to try a small refridgerator with some copper coils inside, but I don't know how bad it will be to have the water running through copper. I guess I could use the flexible plastic (poly) line though.
anybody got one for sale locally? looking for at least 1/3 hp i think.
Plastic doesn't conduct heat well. I suspose if you had a long enough run it might work but wouldn't be very efficient.
DIY chillers seem like the perfect way to be cheap on the front end and pay far, far more in the long run due to electrical costs and their inefficiency compared to chillers specifically engineered for the purpose.
A chiller is basically just a refridgerator.
Not exactly. A chiller directly extracts heat from the liquid being cooled by running the evaporator directly into the liquid. A refrigerator's evaporator is in air, hence cooling the air which has to in turn cool the liquid (2 heat exchanges). Since a perfect insulator doesn't exist, a refrigerator is less efficient and will cost you more in the long-run (as Joel points out) whether you keep the doors closed or not. Both use the same compressors, condensors, etc., so refrigerators have no "technological edge" over chillers. Also, since the amount of heat removed is proportional to the temperature difference, the chiller extracts heat faster since the refrigerant is in (more or less) direct contact with the liquid being "chilled".