Thanks. Is this the stuff you used?
How did you apply it?
Did you remove the fitting and coat the threads as described here?
"If the petcock threads into plastic threads in the tank which have stripped out, use a fuel resistant epoxy like the Fixmaster Fast Cure Mixing Cups (they come in a Pringles-type can, pn. 21425). So the male threads don't bond permenantly, spray on a thin coating of non-stick egg frying Pam type product to serve as the release agent, then with a small thin bristle disposable paint brush, work the Pam into the thread roots and everything else you don't want the epoxy to stick to. Then mix up one of the cups, dab some resin into the hole, work it around with a pipe cleaner, apply the rest to the male threads, and screw it in. Let it sit for about 3 to 4 minutes and give it a little 1/8" twist to break any sort of bond the Pam coating allowed to happen, do it again about 6 minutes into the process, then let it sit for a few hours, and you should be good to go."