Didn’t know where else to put this… @mcdanlj feel free to move it if there is a better place.
I have for some time been playing with and enamored by the notion of making plastic parts from milk jugs.
I think I finally have a process that works, mostly from trial and error and lots of YouTube watching.
In this case, I wanted to make an adapter part of my Automated Shade project. I need to adapt a 6mm motor shaft to drive the end of the shades cardboard tube.
My Current Process:
- Cut up the milk bottle in strips (this is tedious). 1" x 1" or 1" x (length of dish).
- Put in a blender on chop to create granular plastic … sort of. This is hard on a blender so don’t use your wives if you want to stay married. So I got one at a thrift store. Alternately cutting longer strips and laying them in the dish will work but you may have to add more on top of the molten plastic to get the thickness you want. I have also tried a paper shredder but lots of jams.
- Put strips/granular plastic in a pyrex dish with oven paper (keeps it from sticking). This stuff is really sticky when hot.
- Heat in a toaster oven @300-350 until the plastic gets translucent but not so hot it starts to turn brown on the surface. Toaster oven also from thrift store. I tried a bread-making machine but it heated slower. Perhaps a future control hack.
- Pull from oven periodically and tamp out air bubbles with a 2x4 or something that fits in the dish. Air bubbles are hard to get out because the sticky plastic creates a seal around anything you stick into it, inhibiting the release of air. Mmm, brain fart … perhaps a metal straw?
- When the plastic is fully translucent (no white left) and the air bubbles are minimized then pull it from the oven and let cool. You can dip in the water if you want to speed up the cooling.
- To turn tubular shapes cut the material in strips that are as wide as the material is thick ie: square strips.
- Turn on a lathe, work held with a chuck at one end. Turning between centers will probably not hold the material strongly enough.
- The material is a dream to turn if insure good bevel contact when turning, turn at high speed. Does not require a finishing step.
- The material is very smooth and slippery with a lubricated like feel on the surface. I doubt that there are many types of glue that would stick (@Nedman ?)
*I have not yet tried pouring this into a mold, but plan to. I would expect it to be difficult to mold as the material does not flow very well and is incredibly sticky.
- I would expect this material to cut easily on a cnc but it needs better thickness control. I am thinking of some kind of press while it is molten.
So why not just 3D print it.
GOOD POINT, does this method have an advantage?
*Stronger? I know its a strong dense material and threads and cuts great.