Automatic Can Crusher Projects
- No one ever said that you had to crush a can end-on the way many do; the fact is that 13 grams of aluminum is 13 grams of aluminum no matter what shape its in. By far the simplest and easiest way to crush mass volumes of cans down to size would be to squeeze them between a rotating drum and a stationary steel plate. Use a large, curving piece of sheet-metal to create the feed hopper; the feed chute should have a curvature of roughly 1/3 the size of the drum, meaning that it would complete a circle three times the drum's diameter if it made a circle. Placing a few small teeth on the drum will help to feed the cans in; you can motorize the drum if you'd like, but a large crank will work as well.
- Salvage yards don't crush the cans one-by-one; they drop them into an enormous rectangular chamber and squash them all flat with an enormous hydraulic ram. They need all this power to overcome the can's inherent strength, but you can make a similar unit at home on a smaller scale. Start with a 55-gallon steel drum and weld reinforcing bands around the outside. Then, make a heavy, steel lid for the can and size it so that it just fits inside the can. Weld a hinged framework to the top of the can with a one-inch diameter or greater threaded nut suspended over the center of the drum. Now, you can thread a rod through the nut and use it to press down on the plate. You can motorize the rod or drive it with a hand crank, and make the bottom of the drum removable to extract your aluminum ingot. An hydraulic ram will work even better if you've got the resources.
- While you're recycling cans, you might as well find a use for that old lawnmower that doesn't mow or that old car with a snapped frame. If you really feel the yen to build a Rube Goldberg can crusher, you can build a variant on the spinning drum using an old engine, an axle and a pair of large tires. The principle is the same as the spinning drum, but a gas-powered crusher will be able to crush far more cans far quicker than a metal drum. The rubber tire tread will grip the cans and bring them through, but you'll need to secure the rotating tire to a matching tire with a screw-jack to create the requisite pressure. Or you could just fill the tires with concrete and let its mass and hardness do the work.
- If you're looking to impress your friend with your newest fiendish creation, consider making a multiple can crusher using a 4-inch inside-diameter, 1/4-inch thick steel pipe, an old Chevrolet 350 piston with the rings still on it and 250 pounds per square inch of air pressure. You're working with the same piston-principle as the drum-derived mass crusher, but you're crushing a single line of cans. You'll need to bolt a removable 1/4-inch thick steel plate to the bottom to remove the cans and the piston and a similar plate on the top to contain the air pressure. Drill that plate and weld a one-inch nut to the top to receive a piece of threaded galvanized pipe. Connect that pipe to a lever-actuated pressure valve, and connect the valve to a 250 psi air supply. Measure the pipe, divide by five and mark a line of that distance from the bottom of the tube. Drill four 3/8-inch holes around the tube at that line to release the air pressure. Once the pipe is full of cans, place the piston on top, install the cap and open the valve very quickly; the piston will crush the cans and air pressure will vent out of the holes in a mighty whoosh. You may want to remove one of the cans to leave a 6-inch gap between the piston and the cans. This will allow the can to build up some momentum before it meets resistance.