Yes, I had posterd a few months back the procedure of using boiling water and schrader valve on cap vent tube to expand the tank.  It worked well, but I want more.  I like the idea of a heat gun so I could s have better control over what part of the tank expands.  I was hoping that some after market company sold a larger tank.  I guess with 25 year old, discontinued machines we are at the mercy of zilla enthusiasts to make custom parts.