Made-It-Myself Compost Mixer

John Krueger believes in repurposing things, so when he needed a concrete mixer, he made one out of a pressure tank. After he built a better mixer for his front-end loader (Vol. 47, No. 5), he repurposed the pressure tank again. Now, his wife uses it to mix compost.


    “After cutting the top off the pressure tank, I had added baffles to the inside and plating to the inside bottom of the tank,” recalls Krueger. “Those tanks aren’t as strong as you might think.”


    Krueger fixed a driveshaft to the inside plate and extended it out of the bottom of the tank. He used 1/4-in. 2 by 2-in. angle iron for a support frame with two triangular sides. A 4-in. channel iron cross plate is suspended loosely from the tops of the sides.


    A pillow block bearing bolted to the top of the cross plate and a second one bolted to the underside hold the shaft in place on the cross plate while allowing the shaft and tank to rotate.


    “I mounted a sprocket to the bottom of the shaft and ran a chain drive to a right-angle gearbox I attached to the underside of the cross plate,” says Krueger. “A belt drive on the gearbox attaches to a 1/2-hp. electric motor also attached to the underside of the cross plate. The gearbox reduces the motor’s speed from 1,750 rpm’s to 30 to 40 rpm’s.”


    A pipe/handle attached to the cross plate lets him tip the tank. A pin lock with a spring secures the tank in one of three positions. For filling, it can be locked at a 45-degree angle. Once filled, it can be left in a vertical position while mixing.


    Krueger fabricated a hatch cover for the open end from an old piece of cookware. A steel strap with a slot at one end and a steel rod at the other end is bolted to the porcelain cover. To hold it in place, Krueger slips the rod between two bolts at one end and slides the slot on the end of the strap over a bolt in the edge of the hatch.


    “The lid comes off completely, but if we run the motor when the tank is in the 45-degree position without cover, it flings material out the open end,” says Krueger.


    No longer needed for concrete, Krueger has turned the mixer over to his wife to use for compost. She adds chopped-up kitchen waste to other materials, including enzymes and water, to make compost for the garden.


    “She has a recipe all her own,” says Kruger. “She spins it once or twice a week, depending on the material.”


    The only change he made to the mixer in transitioning it to a compost maker was to move the off/on switch. Previously it was on the mixer. The change was for safety’s sake, given the grandchildren who visit.


    “I mounted a 110 lever-type switch to a wall on a nearby building and routed the motor to it,” says Krueger. “For the machine to operate, you have to step over to the switch and hold it down to rotate the tank. It would be almost impossible to continue running if the operator walked away from it.”


    Contact: FARM SHOW Followup, John Krueger, 1112 County St. 2984, Blanchard, Okla. 73010 (ph 405-392-4796).