Here, I show a quick and dirty method to bend aluminum tubing. I am documenting how I built a new bow rail for my sailboat.
Step 1: Build the Jig
Here, I trace the curve that I want on some scrap lumber. This scrap will be used to build the bending jig. I'm just using a couple of old 2x4's. Your wood should be somewhat thicker than the diameter of the tube you wish to bend.
Step 2: Cut the Lumber
Just cut out the traced jig. Use a bandsaw if you have one. I don't so, I just used a jigsaw. Cut the jig to be little smaller than the desired curve. This will allow for the spring action of the tubing.
Since I used two pieces of 2x4, I made a little gusset to hold the two together (2nd pic).
Hint: Add a little bevel inward on the bottom of the cut. This will keep the tubing from popping off of the jig when bending.
Step 3: Don't Bend Like This.
If you do this, then you will almost certainly get a kink in the tubing.
Step 4: Ready to Bend
Here, you can see that I take a piece of scrap (from the earlier cut) and attach it to the table to complete the jig.
You will want to bend from one side only while ensuring the tubing is supported wile bending. While bending, try to keep the pressure against the jig instead of the tubing.
You may want to practice with some cheap amluminum conduit to get the hang of it. When you are ready, get the polished stuff.
Step 5: Mounted on the Boat :-)