Up until recently I didn't know how easy it is to solder aluminum with a propane torch. The torch I'm using has a broad flame so it's probably not as efficient in heating the specific area for welding. A torch with more of a pin point would do better. In either case if you have a propane torch and brazing rods you can weld aluminum. All this can be found at your local hardware store. The rod cost about $3.00.
Step 1: Get the Right Rod.
In the same isle where all the stuff is for arc welding you'll find aluminum brazing rod. I got mine at Home Depot. It has a working temperature of 700 to 750 degrees Fahrenheit. A propane torch burns hot enough to get the job done.
Step 2: Clean Your Joint
Any time metal is being fused together it's always best that you clean it off. Long story short, clean metal sticks to clean metal. I'm using a wire brush on both surfaces. Now you're ready for some heat.
Step 3: Brazing Aluminum.
Apply the flame to the joint until it's hot enough to melt the rod. When you sweep the tip of the rod through the joint it should melt in. If not, heat the joint more and check it again with another sweep. You want the metal to melt the rod not the flame. When everything is cooled off you'll have a strong joint. Check out the last picture where I tried to pull the joint apart in a vise. The metal got all bent up before the joint failed.