[MrForbes]

80/20's main advantage is that it requires little effort to make many different designs with it. It is not a very efficient shape as far as it's strength/weight ratio.

If you want to spend more time designing, you should look into using many other sections of aluminum, as well as other metals and non-metals. Steel can be very effective (look at 1501's 2007 robot), sheet aluminum is also used by them to make strong, light structures. We've used fiberglass pultrusions for our frame, and 842 uses it for their entire robot! Some teams use plywood, you could use spruce, or other woods, which take some effort to design but are relatively easy to work with and can be very strong and light (think of the early airplanes, which were made almost entirely of spruce). For aluminum, look into tubing, both round and square, and angle and sheets. Our robot used sheet and angle aluminum this year.

Also look at the various ways you can connect the parts. Rivets are great, they are light, strong, and quick to replace if needed. Bolts and nuts are a bit heavy and cumbersome, but can be removed and replaced many times. Glues are a bit tricky to apply and hard to repair joints made with them, but for some joints they are the best way to go. Welding is great for thicker alumimum parts, and for thinwall steel tubing (such as 1501 has used).