I'd use a manual Pop-Rivet gun.. They are available at your local hardware store, and a good ACE hardware or similar will have a variety of pop rivets in aluminum, stainless, and even copper. There is a pin through the middle of the rivet, and the gun pulls that pin out and breaks it off.. When it pulls out, the back of the rivet expands to lock the pieces in place.
When you are using it, make sure the panels are firmly together, as if you lock them in a 'loose' position, you wil l have to drill out the rivet and plug it again.
Also, the hardware store will sell washers that are sized to the rivets.. If you put one of these on the back of the panel, it will reinforce the connection.
These are the same type of rivets that I put on my window seals and sun-visors.
Joe Bob says "Check it out"