I have to crush a lot of little cans of cat food for recycling and they do not crush well by stomping. I was in Princess Auto one day and they had pneumatic cylinders on sale. I thought they might be able to crush cans, so I bought one. The first version of the can crusher was a down and dirty wooden version just to see if the concept could work.
While it worked, there was too much play and it sometimes took 2 or 3 shots to crush the cans. But it did prove the cylinder had enough oomph to crush cans.
The next version was a hybrid. It allowed me to play around with the sizes more.
Notice that the fixed end is higher and the pusher smaller. I decided to try crushing "normal" sized cans. The higher back is for the taller cans. The pusher was actually cut smaller than shown in this picture.
This version crushes much better than the prototypes. It crushes flatter and always in one crush for the small cans.
Here are the steps to crush a "normal" sized can:
1. First you crush the top of the can flat. This slightly folds the
bottom over. 2. Then you turn the can over and use the hinge to
hold it in place. 3. Flattened can!
Update Dec 2010: Painted the crusher brown. No picture, it looks the same... only brown. Why brown? Because I have an almost full quart of brown paint.
Update July 2011: Can crusher is now all metal. I welded in supports for the cylinder. Because of the supports, I did not need the back brace and so I cut the frame shorter. I also welded on a bracket for the control. The control bracket goes out and up so that the hose connection clears the edge of the table. I also rounded the one corner since I tend to rest my hand there. The two small holes on the far frame rail are to screw the crusher to the table.
Because of the mods, I needed to repaint parts of the crusher. Here is the frame after repainting:
And the assembled crusher:
