So I have an aluminum race radiator that is in great condition, but somehow got nicked and sprinkle a very small leak in one of the tubes. I think I can fix it with sold aluminum low heat welding rod that melts with a torch. Any sources out there that are good quality? Not sure what is a good and what is crap. We had some we used on transmission cases and work great, but ran out and the source we used has been long closed now.