Plenty of us have experience with paper shredders, but there are all kinds of machines designed to completely destroy other materials as well, from metal and plastic, to entire cars. [Action BOX] built their own heavy-duty shredder capable of dismantling things like cell phones and other robust handheld objects, but after seeing what it would physically shred they decided to give it an actual job creating insulation for the attic space in their garage.

The shredder itself uses opposing metal plates arranged on sets of two cylinders, with each cylinder powered by it’s own large motor. In total, the entire system uses around 1.5 kW, so to make their green insulation project as green as possible they decided to power it with an equivalent amount of solar panels. For the insulation they’re using a year’s worth of boxes from various deliveries, and after a time-consuming process preparing the boxes for the shredder, shredding the strips of cardboard, and packaging it in garbage bags their efforts netted them enough to partially fill the space between four ceiling joists.

Despite not having nearly enough to insulate a garage after all of that work, they still went through the effort to test their insulation against similarly sized fiberglass batts. Despite a brief hiccup where their test equipment caught on fire, they found the cardboard shreds were only slightly less efficient than the fiberglass. They even went as far as to address any concerns with flammability by treating some of the cardboard with a boron solution to add a measure of fire resistance. While this didn’t turn out to be the cost-effective solution they had hoped, as a proof-of-concept it’s certainly feasible especially for those who can’t head to a big box store to buy insulation directly. If you can buy your insulation at the store, though, there are a lot crazier things to do with it.

Thanks to [Jordan] for the tip!