Can anyone recommend a good product to use to try to plug a radiator leak?

I don't recommend any stop leak. Repair the rad properly and you won't be sorry.

Can anyone recommend a good product to use to try to plug a radiator leak?
BARS LEAKS

ALUMASEAL or JB WELD if you can get to it on the outside. Hey moose! you can get a whole new radiator on ebay for $24.99 plus $32.99 shipping. Item #8038923233 by the Radiator Connection.

Barsleak, Alumiseal, anything you put in your radiator to clog a "leak" will CLOG. Plain and simple, your pouring something into your coolant that clogs your system. You will not only end up cloging a leak, but the radiator, the water pump, the thermostat, and any other narrow passages in the block and head. You may was well pour sand in you radiator.

I ended up using the JB Weld option. The leak was tough to get to... in fact it was tough to locate... but once I did I was able to goop enough JB Weld in there to plug it up and it worked like a charm.

Yeah, JB Weld will fix almost anything. It is actually a steel impregnated epoxy with a hardener that cures in about 16 hours. It is good stuff.