Where to buy special plastic epoxy for ThermoQuad fuel bowl?

I've had 4 Thermoquads rebuilt by Steven Stills, Jr. of Edmond, OK [[email protected]] with excellent results. Steven has informed me that he uses the kind of epoxy that is used to glue body panels together. It's referred to as "panel bond" or "metal bond" and is made by 3M, Kent and Wurth. He tells me that nothing else seems to work, in his opinion. Panel bond is pretty expensive; maybe about $60 per tube. Also, I'm not sure what kind of surface preparation you should do.