Pretty neat results. It looks like they have other ideas like cutting boards too.
I am not sure I want to spend 3 hrs every time I want to make a 2x4, but in a special project, it could be worth it. I am also sure I don’t have that many bottle caps.
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I have a ton of HDPE sheet scraps, might be cool to make a few blocks out of them.
My house goes through milk like you wouldn’t believe, so I’m very interested in home/diy recycling of hdpe. But for the methods I’ve seen, the labor is way too high. I still like seeing approaches, and maybe someone will get a low-labor version one day (without excessive capital equipment).
What you need is a big sous vide cooker with temperature control. Unfortunately, HDPE melts at 130C, so you need a different liquid. Maybe some kind of oil? And you need something like a silicone bag to hold the scraps.
Then you could just add a bunch, go pick up the kids. Add some more, make dinner. Add some more, watch some TV. Then make a block.
Can a big crock pot reach 130C?
A fryer can do it with a temperature control. My crockpots only have low, high, warm, and off.
Don’t even need a bag, actually. Put an old pot right in it.
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I was thinking a box that is big enough to hold smashed gallon jugs, so maybe 9" x 9" by some height. Then a silicone heating pad under the bottom with temp control and a weight on top. Insulated so it doesnt waste too much power and just set with a timer.
Maybe the bottom is just an electric skillet or hot plate that has control built in.
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My “sous vide” setup is a crock pot with the power through a thermostat. So I can set it to specific temperatures.
That seems reasonable to me. But better than my oil bath sous vide cooker.
I wonder if there are just used 110V ovens you could get and put in the garage. They used a toaster oven.
That’s pretty cool (sous vide crock pot).
I was just wondering about an oven, too. Out here it isn’t difficult to find someone’s old kitchen oven for nothing or next to it. Of course, those are 220v. We actually put an extra 220 in the new build just so we could have something larger than a toaster oven for powdercoating.
I wonder if they are insulated well enough to make. 110v element practical? Seems like it would be easy enough, physically.
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I realized I had an old electric skillet that I had already ruined for food purposes for a different project. After digging it out I discovered it goes to 400F (or that’s what the dial says).
Dropping a HDPE bottle in and pressing down gently, it melted pretty well, without large pressing forces.
It made a fair bit of smoke, but I think that was residual from before, since it smoked before I added the HDPE. I had set it at the max temperature because I figured I could always dial it back if it works.
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Folks “roll their own” heater coils from nichrome wire for DIY vacuu-forming machines. Can’t see why you couldn’t do the same for recycling plastics into these beams. I’d consider having a heated (and well insulated) form/mold holder. I don’t know how much the twisting/folding is needed to get the plastic uniform and remove air bubbles.
I might also consider and extrusion setup, rather than be limited to a fixed beam length. Pressures could get harder to handle that way, but the “melt zone” might be easier to manage.
The more I think about this, the more it sounds similar to making your own 3D printing filament. Shred the old plastics to establish consistency, push them (maybe with an auger?) into a hot-end to melt, control the size with an appropriate die, conveyer belt to carry off the beam.
I wonder if an electric smoker could be used. Downside is I think they only get up to 275F.
Thats a darn good idea! Now you can just fill that whole skillet up and you’ll have a solid block you could machine stuff out of. Hmm that gives me an idea…(looks at large bin of 3D printed failures, benchys, and test cubes)
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