[jmohn]

IMHO: minimum 3 HP 60 Gal. tank or 5 HP 30 Gal. tank (how much space do you have? bigger is better), be sure you have enough electrical capacity (most larger, more useful, units will need 220 volts), if you go with a smaller tank be sure the pump will supply 4-5 CFM of "free air" (this is the CFM at the pressure you will be using, e.g. mine supplies 7 CFM @ 90 PSI). A loop air system is nice and can be done in PVC although copper tubing is more common here (1/2" ID is generally large enough), just be sure to use PVC (it's not all the same) rated for higher pressure (usually sched. 40 or better), use proper fittings/connections and properly hang it with slight pitch back to a drain (generally at a water trap near the compressor) to prevent "ponding" in the line. Drain/clean/replace the water traps and filters and service the pump and tank periodically and any of the brands mentioned by others will be fine.

Jerry M
'78 SC