So, to start, I didn't do this to save money, instead, I'm doing this for no compromises. I didn't want a pre made tank because there's no place on this rig to put it that makes me happy. So, here's my two gallon tank, made from a the inch pvc coated black pipe. The end caps aren't coated, but after an overnight pressure test, I'm going to coat them with plastidip. Here's the end with the cutoff valve and the emergency relief valve.
I'm losing pressure, so I'll need to find out where. More later.