[mockingbird812]

Ryan,

I have used copper in two shops and like it for its ease of sizing, strength, connecting (sweating is relatively easy to learn), and most importantly it looks vintage cool. It may not be the cheapest option but it is safe. I used 3/4" ID pipe and it is "L" grade which is one step up from the standard "M". It is about 40% stronger than M grade (H Depot carries both). It provides a thicker wall and added buffer of protection (compressed air can be dangerous!).

You're right - The back and forth is to cool the recently compressed air (which is hot) prior to going down-range. I have drains and filters at multiple places around the loop and other collection points to reduce likelhood that water and debris gets to the lift or tools. That back-and-forth section is good for over 8 feet of travel (12&quot; sections) and should cool things down to minimize condensation. For some reason I did not have much of an issue with condensation in AZ!! [img]<<GRAEMLIN_URL>>/hmmm.gif[/img]