Brazing

I gave aluminum brazing a shot this weekend. Its pretty cool really. I got a pound of rods from DuraFix. (Check their sales video. Another company that sells the stuff and also has a video is Aluminum Repair.) I also picked up a mapp gas torch kit from a hardware store. The idea is that you get the aluminum up to a certain temperature such that the silver alloy in the rods will melt, but the aluminum itself won't. The alloy act as a sort of metal glue.

It turns out that the metal needs to be pretty clean and further it has to be cleaned the right way. A stainless steel brush was provided with the rods but I soon discovered you really need two: one for pre-cleaning and one for manipulating the alloy while hot. To to make a joint its a good idea to tin both sides.

It also turns out that mapp gas is plenty hot enough to melt aluminum. I slagged a couple of pieces before I got the hang of it. Probably need to back down to propane or even butane.

After around five or six attempts I got a pretty strong joint. Its the one in the picture. I managed to crack the joint open but it's still pretty strong and it took a hell of a beating just to get to that point. To be able to make that strong of a joint with a couple hours practice is pretty cool. Supposedly, after I master the techniuqe the joints will be stronger than the original metal.

I figure this brazing thing can be very useful for making custom aluminum chassis for my robots. When it comes time to make my RoboMagellan bot water tight I think I'll be using this technique.

Anyway I just wanted to do a quick post with a couple links. Sorry its not longer and doesn't share the experience more in depth.