My first precious plastic machine!
Hello from the Pacific Northwest (USA). I am excited as heck to show off my first machine my wife, brother and I made! With the help of Precious Plastic USA (Based out of Portland, OR) we were able to construct our shredder! We were lucky enough to get our hands on an old school art desk, and an ATV winch from Harbor Freight. We are using a belt drive system from an old car 12V battery set up on a constant flow charger until we can afford a converter to 110.
UPDATE: We ordered a pulley for the belt drive but it didn’t produce enough torque. We have a chain and sprockets coming by the end of the week. We also reversed the sides to where the larger one is on the shredder, and the smaller one is on the winch itself. Wish us luck!
I made a benchtop injector and even that takes a lot of force on the handle. You may be putting a lot of your weight on the handle. I would consider adding some extension on the base, I don’t think the wheel is enough to keep it from tipping unless it is anchored.
We considered filling it with concrete…. we’re rednecks lol
just weld a triangle or square (easier) to the bottom as suggested in v3 or make it part of your your bench (one of the leg’s tubing). the concrete won’t change anything I am afraid; it’s good though to bolt into the ground as Stan mentioned. Consider however 2 adults hanging on the lever to fill an iphone mold .. I think I added the linkage designer to the PP resource page but in short it’s best to have a look at @andyn‘s machine to get an idea. You need quite some power to pull it out. There are also simpler designs to tie up the plunger horizontal along the bench, no framework needed, actually. Please also consider the PP machine is just one among a few thousand variants. PP added in fact just ‘precious’ in front of ‘plastic’ .. 😉
I made a few changes to the injector:
support leg out front for balance
It works like a charm. Is there a thread within these forums that covers the basics about injecting different types of plastic? I have been experimenting and trying to research whenever the kids let me, so not very often.
Glad you got it running.
In the PP download kit that you may have used to build the injector, there is a very basic user manual with a section on injection. https://preciousplastic.com/en/videos/download.html
I captured some of my ramblings in this thread. https://davehakkens.nl/community/forums/topic/portable-desktop-injection-machine/
I would start with the safer plastics like HDPE. Even with that, in a garage with an open door, I could tell the fumes were not a good thing. Looks like you may be set up to work outside, that’s probably best. If you got kids around, put a cage of some kind around the hot end. I find it is easy to forget that it is wicked hot and to brush up against it.
I find it is fun to hack together different mold approaches to get to the shaped part you want.
Have fun, stay safe
yeah, there’s currently no template or structure in place to enable or harvest user submissions. Currently we hand pick user posts here manually. But if you look at the v4 forum posts there is some pattern in sight. Most important for others and automatic content collectors is :
– machine specs
– times, temperatures, materials used
– photos which ease the text overhead but don’t exactly make it easy to document for real
– very important: a photo of a cat doing stupid things
Here is an example of the simple mold i made just to get started (i have 3 now). The multi color pictures are of various bottle caps we ground up. The plastic in the picture is not what we are currently putting in the injector. The stuff we use is much finer. Warm up time (empty) for 10 minutes, and a cook/heat up time with the plastic loaded for 10 as well. I am noticing with various types that i will get what seems like pockets of air/space between flakes, and goo.
I am really having problems trying to gauge Temperatures, times, etc. with each type of plastic. I have the heat chart, and have been looking online for other tips and tricks i can do to help it go smoother.
So far https://davehakkens.nl/community/forums/topic/types-of-plastic/ this has been pretty helpful
Some thoughts. Bottle caps are a mix, some are LDPE, some are PP, a lot of them are not marked. I would start with marked HDPE bottles (laundry det., milk jugs, shampoo, etc). In my machine, I use 200 C. I found that to get a good melt, it takes lot longer than 10 min., I also do a lot of compaction of the melting plastic with the nozzle blocked off. The other part for avoiding voids is to keep track of the mold volume. I have not been able to fill a mold that’s much bigger than about 2/3 of the stroke volume my injector. You still want to have pressure on the mold when it is full.
I’m not sure you need to mix it, I just compress it with the piston. I typically fill part ways then compress and let sit under pressure for 5 or 10 min. I then add and repeat. One way I know I’m ready to press is looking at the plastic stuck to the underside of my piston. If it is all melted, looks like soft bubble gum, I’m good to go. If I still see flakes I wait and compress.
My machine has a larger diameter and a shorter stroke, so I think the melt takes longer. I usually take an hour or so for the first press with HDPE.
So i was able to make these today! 2 from HDPE and one from a mix of bottle caps.
Cool, you should move your inlet more to the bottom left where Mt. St. Helens should be.
I’m thinking of going dumpster diving in a local laundromat because those bottles have the best colors
I would cut one of those up to see how you are doing on voids.
Hey, I am from the PNW as well and was looking at Precious Plastic USA in Oregon for the shredder kit he provides. I saw you mentioned using a Harbor Freight winch and wanted to see how you like that. I was actually looking at getting one of the 120VAC electric hoists, similar idea, but I always hesitate with the Harbor Freight stuff. Especially if I plan on pulling it apart to use it for a different purpose. I have done some tests cutting HDPE up by hand and melting things in the oven and compressing things manually in simple wood molds or tin cans. Results have been good, and I like the results, so obviously the next step is improving the process. I am interested in seeing what else you make, keep it up.
A winch sounds great, slow as fuck but powerful. I was also thinking about experimenting with a roller shutter door motor, you can find them on aliexpress for less than $150 and these things can lift 600kg. This one for instance has an output torque of over 400n.m which is plenty for the Shredder
Yeah we got our shredder parts from PPUSA too.
We got our hands on a 2hp motor from Harbor Freight, and then ordered a surplus gearbox online from https://hgrinc.com/. The winch was awesome while it was working. The only problem we ran into was that it ran hot FAST. They Aren’t made for continuous running. We wound up running fans on it and that seemed to help. I have considered rigging up a sprocket on one just for the hard to grind stuff.
roller shutter door motor seems like a good idea… craigslist here i come lol
so i have had a mix of HDPE between 2 cake pans in my compression oven. I have had it at 360 (f) for 30 minutes, then i let it cool for about 20 or so under pressure outside the oven. I keep getting these little gap/holes in the finished product. What is causing this? I know there are some other types of plastic in there, but could that be causing this? Thoughts?
The overall piece
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