[sgreco]

I must admit I'm a little confused...Why add unnecessary weight? Just because you can't weld aluminum doesn't mean you shouldn't use it. Rough estimates would say steel is about 3 times the weight of an equivalent piece of typical aluminum. So with 1/16 inch wall steel, and 1/8 wall aluminum you have half as much volume with the steel. So for a size that would weigh 16 pounds in aluminum, the same volume will weigh 24 pounds in steel. Do you really want to waste that much weight into a frame that's strength would suffice in something that is much lighter. Plus the fact that you can also use 1/16 aluminum in places of low contact. My team used half 1/8 aluminum and half 1/16 and we never had any problems at all. True we welded it, but there are certainly ways to bolt aluminum that are very structurally sound and are still much lighter than welded steel. It's your call though. There are some advantages to steel as you mentioned, but I don't think the added weight is worth it.