Yeah, plastic shouldnt be used for air lines. Copper is the best to use simply because of ease of use. Black pipe is a PITA because you need to have it threaded. Get a piece of braided hose with the same ID/threads as your compressor outlet. They sell an adapter to adapt threads to copper lines. Come out of the compressor, and into copper line, make the run up towards the cieling, then go around the perimeter to wherever your drops are. "t" the drops out of the top and loop them back down. This helps to only pick up dry air in the lines. also, T the regulators out of the side of your drops and install a drain at the bottom for water and stuff. The reason for hte flex line is to isolite vibrations from the sweat joints so you dont shake them apart.
If you choose to do this with black pipe instead of copper, you need a filter right before EVERY hose connection because the moisture in the lines rusts the insides of the black pipe and will flake off the coating on galvanized, and it will get into your air tools. With copper you can just install a filter right before each drop.
Slant the lines ever so slightly back towards the compressor so the tank collects the water. You can sweat them with 95/5 tin/antimony solder, it holds up fine, just remember to brace the lines to control vibration.
Jim
