Since I am build a new shop, I figure I will put the compressed air lines inside the walls. I am considering using 3/4″ PEX-AL-PEX, which is a variety of PEX that has an aluminum layer. You can buy kits from Rapidair that use PEX-AL-PEX, and those include aluminum mounting blocks for putting on walls. It will be nice to have it routed inside the walls, with drops at different locations.

Anyone used this technique?