Black iron here but posted to say..........
25 or so years ago I took a roll of 3/4 copper and was going to run our well water through it.....tossed over part of the exhaust pipe on our wood furnace.This ain't a "woodstove" in the general sense........Its the biggest yukon they make.
Anyway,got nervous about potential steam and pop-off valves and in general,"hold my beer" issues,so it never happened.
Fast fwd'ing....this coil of copper has very nice "ribs" solder'd to outside to act as spacers for individual coils.It's been in the attic all these years.I'm now installing it on our compressor as part of overall moisture control.It'll be put right at outlet from tank.....in a vertical orientation.Slightly un-decided about whether to simply let it drain back into tank or run a Tee setup drain(leaning twds Tee).
From coil,the line(black iron in our case)then will go to fruitjar/regulator.We also have a very nicely done Franzinater expansion tank between comp head and tank.Even wrapped it with 1/4" copper tubing thats connected to shop water supply.When using compressor heavily....will go to shop sink and crack the cold water on.This gets enough flow through,that it really cools Franz chamber.I shot a 40% lower temp on the line btween head and tank with temp gun....before/after.
The new coil is long over due......just being lazy.But we've never really had moisture "problems".....as comp is in a climate controlled area.Good luck with your air-lines.Try to build in as much flexibilty in design as possible.IOWs....don't bury or hide lines or parts of system.Look at it like you may want to re-configure at some point......adding lines,refrig units,coils....that sort of stuff.BW