Turning Plastic Milk Jugs into a Useful Tool

[Peter] obviously enjoys getting to work in his wood shop. He also likes turning things into other things. With his latest project, he combines his two hobbies by turning plastic milk jugs into a plastic joiner’s mallet.

[Peter] started out by collecting and “processing” the milk jugs. Milk jugs are commonly made with HDPE. HDPE is a petroleum-based plastic with a high strength-to-density ratio. It’s easy to recycle, which makes it perfect for this type of project. We’ve even seen this stuff recycled into 3D printer filament in the past. The “processing” routine actually just consists of cutting apart the jugs with a razor blade. [Peter] mentions in the past that he’s used a blender to do this with much success, but he’s unfortunately been banned from using the blender.

Next, all of the plastic pieces are piled up on a metal try to placed into a small toaster oven. They are melted into one relatively flat, solid chunk. This process is performed three times. The final step was to pile all three chunks on top of each other and melt them into one massive chunk of plastic.

While waiting for the plastic to melt together, [Peter] got to work on the handle. He put his woodworking skills to good use by carving out a nice wooden handle from a piece of cherry wood.  The handle was carefully shaped and sanded with a variety of tools. It is finished with some linseed oil for a nice professional look.

When the plastic was mostly melted together, [Peter] had to get to work quickly while the plastic was still soft. He pried the plastic off of the metal tray and stuffed it into a rectangular mold he made from some fiber board. He used a heat gun to soften the plastic as needed while he crammed it all into the mold. With the mold suitably stuffed, he closed it up and clamped it all shut.

Once the plastic cooled, [Peter] had to cut it into the correct shape and size. He took the solid chunk of plastic to his band saw to cut all the appropriate angles. He then used both a drill press and a chisel to cut the rectangular mounting hole for the handle. The plastic piece was then shaped into its final form using a belt sander. All that [Peter] had left to do was slide it up and only the handle. The shape of the handle and mounting hole prevent the plastic piece from flying off of the top of the handle. Check out the video below to see the whole process. Continue reading “Turning Plastic Milk Jugs into a Useful Tool”

Printing a boat made out of milk jugs

Today, groups from all over the Pacific Northwest will take up their oars and head over to Green Lake for the 42nd annual Seafair Milk Carton derby. The team who builds the fastest boat made out of milk cartons wins the regatta (and $10,000). This year, we’d put our money on the 3D printer group from the University of Washington; they printed a boat large enough to carry a person using crushed melted milk jugs.

After building a huge extruder to feed shredded HDPE plastic through a nozzle, the team repurposed an old plasma cutter to serve as an 8-foot-long 3D printer. There were a number of problems the team ran into – getting layers to fuse together, finding a suitable printing surface, and perfecting the art of squeezing melted milk jugs through a heated metal tube – but the final result is impressive, to say the least.

As far as how lake-worthy the UW team’s boat is, we have no idea. The milk jug regatta will be held later today, and if you have an update of how the team fared, send us a tip.