I guess A-36 steel? not stainless. I can see doing some automation some day but being my first rig I wanted to keep it simple and manual.. I planned the build to be upgradeable.. The frame will handle whatever and I have room for electronics and solenoids when the time comes. I am going to install a panel area that will house pump switches and wiring for now. I want to be able to plug in the power and connect propane. Trying to keep it clean! JJ