ArtMetal

I can't give you the exact info right now, but there is a solder that sticks aluminum to steel, or just about any other metal for that matter. I have used it on alum to steel and alum to copper as well with good results. It's fairly inexpensive and can be done with a bernz-o-matic torch. It comes as a soldering paste or as paste flux and wire solder. Use the same tehnique as silver solder. I would give you the info but I left the stuff with my dad and he is on vacation right now, and my memory is pretty much short term anymore, LOL. I like the rivets and screws idea myself though.