For my air lines, I use PVC. I know a lot of people have posted warnings about how dangerous PVC is, but I have seen steel pipe that has exploded from air pressure, and it is not a pretty sight. I have never seen the results of PVC pipe exploding from air pressure. My air pressure is limited to about 130 PSI, and I have never had a problem, except for when my brother hung an old shop drop light from my air line and the bulb melted the tubing, giving it a weak spot.
As far as the compressor pump is concerned, I have an Eaton pump on my compressor. I bought the pump about 6 years ago from Eaton, on e-bay. The compressor was originally a PUMA 5 HP that was built about 1985. The original motor went out and I got a new one from Northern Tools. The pump then went out, and it was replaced with the Eaton 3 CYL unit. The Eaton Pump just blew a head gasket last weekend. I checked and found that all the head bolts were loose. It had been quite a while since I had checked them. I sent them an e-mail on Sunday asking about gaskets for it. I got a response from them at about 6:15AM on Monday, telling me that the gasket set is $25 with new reed valves. I called to order them later that morning, figuring that the price had to be for one cyl, so it was going to cost me $75+ shipping to replace them all. I was surprised to find out that the "set" was for all 3 cyls.
Although I did make sure that I installed the right pulley to get the RPM's where recommended, I have to admit that I am not the best at doing preventive maintenance. Where this compressor is located it gets quite hot, and should atleast have a fan there. For the thing to even work under those circumstances is a miracle. I can't complain about the Chinese built pump.
On an added note.... Several years ago I spoke to Matt Cain of Eaton compressors about his pumps being built in China. This was after someone posted on another site that their pumps were garbage because they were built overseas.Matt told me that, while he does have his pumps built overseas to save costs, they are built to his specifications. He went that route when he was missing a lot of sales because people were not willing to pay the cost for ones Made in the U.S.A. He also told me that most all pumps are built off-shore, even if the compressor is listed as being "Made in U.S.A." If I needed to buy another pump or compressor I would not hesitate to buy another Eaton.
Aaron