My pan had some real bad leaks and pinholes all through it. I drained my oil, scraped my pan with a 1" putty knife, scrubbed it with a mini wire brush and sprayed it with brake cleaner a few times. I then used "fix-it-stick" from the plumbing department at Lowe's(or at any auto parts store) to seal it. The "fix-it stick" is nothing more than a tube of bonding putty that you cut a section off of and mix the outer layer with the inner layer. I made small batches and patched all over the pan pushing in on with my fingers overlapping joints. Before it sets you can wipe it down with water to smooth it out some more. It hasn't leaked a drop since and my pan was REAL bad.
I tried JB Weld and it was too runny and flaked off when oil got behind it. Good luck.