The local radioshack here didnt have it. The guy called up the main place, and they said they didnt stock it or something. He was being nice i guess, and called to a few other far-away cities and asked around. No luck for me.
I needed to glue a heatsink onto my Velocity 4400 video card. The mosfet on it would get hot enough to make water steam off of it (seriously, it would). The whole videocard board around it was discolored a dark brown. Instead, I bought a tube of RTV sillicone gasket maker. It works good. Probably not good for high wattage, but good enough for a little mosfet.
Ive used JB weld epoxy on a PII-400, it seems to work good. Using my finger-thermometer, the back of the CPU card doesnt seem to be hotter than the actual heatsink. Also, your milage may vary with the epoxy.