Step 1: 55 gal. barrels / drums
Step 2: Cutting the door
I found a large piece of scrap plastic to make a door. Again, I traced the template, cut, and filed the edges.
Step 4: Drilling pivot holes
Step 5: Assembling the PVC
It's hard to see in the picture, but the PVC is screwed into the hole at the top of the barrel. I found a piece PVC that was threaded. All pieces are 2" PVC.
When completed, the top of the barrel will become the bottom of the tumbler. Air will flow in and through the PVC piping.