Hey, I found a set screw under a transparent/yellow plug. Been too busy hauling iron to work on it again but I'm still going to send a picture and results when I get around to it. Need to chip the JB Weld off the Relief Valve stem. I know it works b/c it blew at whatever it's rated at. Relatively a newer tank. Have to make music for the coming in of the New Year. See ya then and y'all be safe.