Managed to find a 700W continuos office shredder for cheap on the 'jiji; hoping that it can potentially handle shredding plastic. The current plan of action is to melt down plastic scraps in a junk toaster oven into sheets then try to shred them. I'll be updating here as it goes to see what the end result is. Waiting on a silicone baking tray so the plastic can actually be released. If this does work I'll manage to save a bit over a grand and kick start this process sooner than I expected
Yours truly,
Ayydan
First try with melting PLA down and shredding shows promising results. I melted it down at 230C for 30 minutes on a silicone sheet in a VV toaster oven. The end result was reasonably flat, but wasn't perfect. My main issue is that the high spots made it hard to feed into the opening of my shredder since it kept triggering the safety mechanism. In addition to that, they were thick enough to trigger the overcurrent safety. I've ordered some borosilicate glass sheets I want to try using along with some spacers to see if I can't get a more flat surface. I'll likely need to go to VV to grab a piece of cast iron or something to use as a weight to apply more pressure.
Despite these hiccups, the shredder was eventually able to shred most of my test sheet and gave excellent output, so I'm hopeful that thinner, more consistent sheets, will give even better results. I ran this test with 150g of material, which filled a reasonable portion of the silicone sheet, but since I'll be trying with slightly smaller glass sheets I'll likely have to downscale to 100g for my next test. I'll try to target ~1mm in thickness, as I've seen some other people online have had reasonable success doing this to punch guitar picks.
Yours truly,
Ayydan
Why not press between two borosilicate glass sheets? It would make release easier, and you could use a spacer (feeler gauges because gauge blocks are expensive) to get an exact and reproducible sheet thickness.
You just aren't patient enough. I ordered some glass sheets already haha
I'm planning to use some nuts or something to set the thickness for a quick test. Currently, I'm planning to still use the silicone baking sheet on top of the bottom sheet of glass to help with releasing, in case the two get glued together. Just need a small but heavy object to put on top of the top sheet to help it apply force. I can't imagine it'll need too much at these low volumes though.
My current main concern is centering the top sheet, since the scrap isn't even the top glass may shift and not press everything. I might be able to add it after the inital melt has started, but even with borosilicate I worry about temperature shock
Yours truly,
Ayydan
Looks like it's a good thing I used the silicone on the bottom sheet, the PLA got proper stuck to the top glass, and wasn't coming off with a putty knife. I'm putting it in the freezer for a bit to try and release it, but for my next experiment, I'll likely need to use silicone on the top sheet too. I think I may want to try and cast my own form in silicone so I can get more consistent results, but don't want to commit to buying a casting set :/
Yours truly,
Ayydan
Okay, good news and bad news...
Good news is, the plastic released from the glass and shredded beautifully (I also disabled the hand guard sensor to make the shredder easier to use.
Bad news is, the PLA shattered when frozen, so I was only able to test with a partial sample. In addition, it left some nasty residue on the glass, so I will definitely need a secondary sheet of silicone to prevent sticking. This is making me more convinced that I will need to cast a custom silicone tray...
Yours truly,
Ayydan
Yay! I've been wanting to become equipped for casting silicone for a long time so this may just be the push I needed.
Okay, silicone sandwich with glass to help keep it flat has worked well, the passive thickness achieved was readily shredded with minimal effort and gave great granulate. Unfortunately, this process is kind of a pain and gives weirdly shaped output. I can probably make it work for now, but I would still like to try designing my own pressing system...
Yours truly,
Ayydan
also, rafts shred beautifully with no effort
Yours truly,
Ayydan
