Yeah Sch 40 is pretty heavy duty for air tanks. Sch 10 would be more like it. You can buy the true air tank ends that are a little different than standard caps, but they are a manufactured stock item nontheless. The bung holes for inlets/outlets and the drains are welded on and you've got yourself an air tank. They are pretty easy to do, which you could do yourself. But if you want to have them certified, then a company that's properly registered with the state has to build them. Sounds like your on the right track though. Air starters are so cool... I'm jealous.
