Using a propane torch and some aluminum brazing rods is a quick way to bonding aluminum without using a welder. It makes for a very strong bond and with a little practice can be done quickly with great looking results.
Step 1: Propane Torch
The blue Bernzomatic will work just fine but I prefer using the yellow premium touch as it's hotter and works much quicker.
Step 2: Brazing Rods
You'll also need some aluminum brazing rods. I purchased all of these things at Home Depot.
Step 3: Cut Aluminum Tubing
What I like about using aluminum is it's soft enough to cut with ordinary woodworking saw blades.
Step 4: Chamfer Edges
I'll then chamfer the edges to allow a channel for the brazing material.
Step 5: Wire Brush Aluminum
Before brazing it's very important that the aluminum is clean.
Step 6: Heat Up Aluminum
Clamp up the tubing and start heating the aluminum with a propane torch. Aluminum will start to melt at 1200deg Fahrenheit but the brazing rod will melt at around 700deg so we want to get the aluminum hot enough to melt the rod without melting the tubing. Getting the tubing hot enough may take 4 to 5 minutes. You'll know when it's hot enough when the rod starts to melt on contact.
Step 7: Braze the Aluminum
Rub the brazing rod along the channel until it's filled in and finish it off with some more heat. If you don't get the aluminum hot enough the brazing rod will just clump up and not stick to the tubing. This takes some patience and practice as my first few tries resulted in failures and ugly joints.