I do a lot of mechanic work, but occasionally I get something different in the shop. I recently had the opportunity to do a little gun smith work.
A customer brought in an old Remmington 11-87. This is a standard gas operated semi auto shotgun. This one is a little bit more interesting because it is an uncommon left hand model.
The magazine tube is brazed or silver soldered in to the frame. Some how this connection had come loose. On this gun the magazine tube holds the whole fore arm together and without it the gun is useless. The owner had tried to solder it back together with regular lead plumbing type solder but it did not hold.
I took the gun entirely apart and cleaned the mating surfaces up with a small stone in my Dremel tool. Once it was cleaned and fluxed I fired up my torch and used some silver solder that I normally use for high pressure connections on refrigeration equipment. It is hard to see in the video, but the metal has to be heated up until it just starts to glow.
The metal was a little discolored from the heat, but you can hardly notice with all the rust on this gun. The owner was very happy to have it fixed in time for the spring time migration.