Some new ones. I loaded up on tarps. They are cheap and are not meant to last. But at a dollar each you can't go wrong. Great for covering tillers and the like if you don't have a shed.
I have done .063" aluminum, but I try not to go over 16ga steel. It needs more support as it bends in the middle. More clamps help, but there are limits.
Anyone interested in one of the aluminum cases at harbor freight may be interested to try this coupon code which drops the price from $25 to $20. The HF I go to let's me simply tell them the coupon codes and they type them in.
This coupon code is special due to the fact that you are supposed to have to pay to be an inside track member. I know that is a 15 yard truckload of BS as my wife used one of my ITC coupons in checkout and they didn't hesitate to give it to her. That was the last time I had a membership.