Precious Plastic - Bazar Guide

Bazar Guide

— WIP (Work in Progress)! —

After 4 years of professional experience, speaking with thousands of users and customers, from hobbyists, SMEs, schools, universities, bottled water companies, and packaging vendors, … here are our conclusions, developing, fixing, and supporting Precious Plastic designs at scale.

Things to consider

  • All Precious Plastic based machines have been developed with very limited capacities, within a very short time, lacking engineering, professional and/or manufacturing skills or resources. In return, please don’t expect too much from it. It’s ok for hobby use but for professional scenarios, including education contexts. It’s better to watch out for reputable sources, being in the trade on a professional base.
  • The majority of Bazar suppliers lack professional equipment and skills.
  • Most of the machines lack regulatory compliance. Even if they claim it, please be very careful and don’t forget that the suppliers have a very short track record.
  • Be prepared to re-sell that machine for a fraction of its initial investment. Precious Plastic is rather an island. In return, those machines don’t have much market value. There are lots of disappointments being reported, ignored, and censored.
  • Please ignore ‘featured’ vendors. PreciousPlastic itself is known for playing issues down (often censoring it), nepotism, misinformation, incorrect specifications, abuse in many aspects and incidents, defamation, manipulation, unfair competition as well false or bold claims - accompanied by reckless and irresponsible behavior against the community. The list is long, don’t get under the bus as so many already did!
  • Your communication on the Bazar is not safe! We’ve seen privacy breaches not only there, being used for extortion but also in other rather dramatic cases. Recently, PreciousPlastic also removed key contributors with made-up stories, causing job losses and bankruptcies for lots of people.
  • Please search the vendor by its name on the internet. Avoid buying from the Bazar altogether. We’re currently investigating ‘Precious Plastic’ for various criminal offenses and we recommend not supporting them in any way!
  • Precious Plastic Bazar is after all dominated and controlled by v4 team members, enjoying sales also through the backdoor on the project’s mainpage

General advise

  • avoid any vendors with renderings or stock photos only, also check for their background on social media
  • always check Google with similar search terms, there is always better offer on second hand markets
  • involve somebody with expertise before throwing big $$ at this, for the bespoke reasons above
  • most of the machines include consumables as heat-bands, cartridge heaters, bearings, shredder knifes, etc… make sure you have a list of these items and alternate sources

Products & machines to avoid

Precious Plastic - Injector

Whilst it seems the more simple machine, it’s also the most clumsy and difficult to use. It’s easy to build it wrong. With up 2 people hanging on the lever and one to hold the machine back, it’s clearly a no-go. Go for an Arbor injector instead. Other than that, don’t spend more than 2000 Euro on it. The material involvement is around 500 Euro. We have seen machines in the bazar for 5000 Euro whilst not addressing major issues and important details.

Must have

  • Make sure it’s stable and robust, wood is not an option!
  • Mold pressing mechanism is a must since the thread interface will often clog up.
  • Good heat insulation.
  • Short unheated way to the mold. Plastic is cooling down and thus, clogging the nozzle in very short time. It’s a matter of millimeters.
  • Bronze/brass tip, that reduces overall friction and the wear out of the barrel since the plunger can have a smaller diameter as well.

Good to have

  • A valve, this ensures fast and safe cycle times and enables using heated molds. It’s a matter of seconds to do a good shot. Please see what can happen here.
  • Integrated fume exhaust system, at the nozzle and hopper inlet
  • Step-less mould height adjustment. The car jack became tradition but still, it’s tedious to use, especially when using heated molds.
  • Hardened barrel, pretty much all injectors use mild steel barrels and can wear out quickly - making the plunging even harder over time.
  • 2 mold interfaces: one with thread and a conic nozzle
  • Guide pins or slots with set screws for mold placement

Here some examples of good injectors

Here some examples of rather bad injectors

Precious Plastic - Shredder - v2.1

Due to its cutting diameter, it requires up to 2-3 kW to provide acceptable results. Unfortunately, at this torque, drive shafts break often. Watch out for an updated build with auto-reverse and at least a 30mm drive shaft. Please be warned that this device can be very disappointing since you still have to push the plastic into the hopper and it jams a lot.

Precious Plastic - Shredder v3.x

Whilst it’s finally has a bigger drive shaft, it’s still not optimal since it depends on bolts, still not optimal considering the forces involved, much at expense of the couplings. Also here, 2 lock nuts are required for each end of the drive axle.

Other small shredders & designs to be avoided

  • Shredders with wrench motors. This heat up in no time.


  • Hand cranked shredders using the v2x or v3x design. It’s requiring a lot more power than this short lever.
  • This here for instance is a no-go! The Gearbox is way too small, with entirely inadequate wiring and electronics. Another red flag for using aluminium.


  • Shredders built on a beam framework only. With the right motor, you need at least mount plate of 15mm
  • Avoid oversized versions, it’s just not made for it


  • Shredders with insufficient motor power (1.5kW)


  • Shredders with too long hoppers. This will invite accidents since the device is rather useless this way.

Precious Plastic - Extruder v3.x

Avoid any cheap builds with a wood auger at any cost. This can break quickly. The very design is known for breaking since it’s disproportionate handling of thrust forces. Expect very little outcome of it. You can make 4x4 beams and baskets but that’s it. Do not attempt to make filament with it, except for follow-up pelletizing.

Precious Plastic - Sheetpress - unless it’s built with adequate machinery which isn’t the case for 99.99% of the cases.

Major issues:

  • cartridge heater blocks are often drilled with 12 mm but leave up to 0.4 mm play. It’s rather impossible to fill that void with the suggested heat putty. In return, expect pre-mature life expectancy for the cartridge heaters.
  • it’s impossible to build good it without industrial equipment.
  • the Aluminum press plates bend over time
  • extremely high power consumption

Precious Plastic - Extruder - Pro, aka “Version v4”.

The v4 extruder finally addresses essential issues of the v3 extruder but comes at great expense

  • exclusive and incomplete design - be sure you have access to spare and replacement parts as the bearings, etc…
  • difficult to make, requires precision equipment
  • it’s ok for some occasional use, it’s using a mild-steel barrel, wearing out quickly with daily use, make sure you have access to replacements
  • don’t spend more than 3000 - 4000 euros on it, it just doesn’t worth it. To give some perspective, a proper extruder with 35 - 45 mm screw diameter is around 5000 Euro on Alibaba. These machines are produced with high standards and quality, support warranty is provided well.
  • the screw and barrel are about a third bigger only - that’s very little improvement
  • the recommended specification of 1:5 gearbox doesn’t match our tests, as for a 1:10-1:20 gearbox instead.
  • users repeatedly reported problems with filling up the brick mold
  • proper bearing housing
  • 3kW - 3 phase motor, do not use single-phase motors!
  • proper cabinet for the electronics
  • the recommended ratio of 1:5 is rather a misfit for quality extrusion. most plastic types wanted around 1:15 - 1:20
  • barrel and bearing housing with less of 0.1 mm run out or tolerances, across all parts
  • make sure there is a proper barrel mount, it flexes easily
  • make sure there are 7 quality heatbands, this here is unacceptable quality:

Here is another bad example

  • barrel opening is way too big, 4x2cm is appropriate for this torque/diameter
  • little to no back thrust handling. the extruder can create pressure up to 4-5 tons. you need at least 2 thrust bearings and a taper bearing
  • disproportionate mounting of the barrel regarding more heavy loads

Precious Plastic Shredder - Pro / v4

Just no! After doing excessive tests, at a high expense, please avoid this at any cost! The design requires rather 4kW but isn’t made for. Also using a sieve (200 + Euro) will destroy the shredder due to design issues, being also consequent censored and ignored. Please go for an industrial shredder instead. You will get a lot more value, also in the long - run. The chamber is unstable and often there are no hardened blades. Even Hardox blades wear out quickly. On top, shredders that size, are not done from laser cuts, period! It’s very disappointing to see almost no standard or best practices applied. In any case, make sure, you get it with auto-reverse and proper wiring & PLC.

  • Don’t forget that workshops have legally binding requirements for insurance. There are only a few which offer this design with compliance.
  • Maintenance & assembly requires special tools and lifting equipment
  • The average price/value ratio is way off compared with commercial offers, from established vendors
  • Since the mesh (sieve, screen) doesn’t work and will destroy the shredder, you will have to re-shred the plastic a lot, up to 5 times. This is in particular problematic since smaller flakes stresses the chamber to it’s maximum but also wear out the blades a lot faster. Common practice is to have a traditional grinder after shredding.

Designs to avoid

Remark: There is a reason why shredders with this chamber size and the resulting torque need to be built in metal and precision.

Must have

  • heat-treated, CNC cut, annealed and precision ground blades
  • 2 lock nuts on each shaft end
  • proper cabinet for electronics
  • status feedback LEDs
  • auto-reverse and various motor protections
  • ball bearings embedded in CNC cut housing
  • compliance with local regulations
  • enclosed hopper, eg: with door - plastic tends to jump out, very high and fast
  • CNC cut chamber
  • hooks/lifting supports

Good designs

Sources & Suppliers to avoid

  • Precious Plastic - so-called “Head-Quarter”. Known for bad customer support, outdated and overpriced designs. Avoid any ‘starter-kit’ or whatsoever! They will answer your email after a year, telling you that your workspace is unfit, without even seeing it. In the meantime, the gang keeps harming the project with crappy designs and hilarious claims, of course - paid by you and everyone else. More about it later.
  • Citizen-Scientific-Workshop, rather bad service and obviously shady designs (seriously, a joke) but being promoted since long for no reason. He’s got no expertise nor the proper equipment but he’s enjoying (and abusing) moderator privileges and interfered with community communication and discussions for years, with hit and run/ban style destructions, at the expense of hundreds of users. To be avoided at any cost. Till today, not a single OpenSource contribution, but bullying other and actual long-term contributors.
  • Recycle Rebuild + Sustainable Design Studio - just no, in so many aspects. No background, no skills and overpriced for what it is.
  • LE RECYCLEUR FOU. Whilst these products have seemingly better quality, please consider them extremely overpriced for what it is. LE RECYCLEUR FOU enjoys as other v4 members privileges as sales coming from the project’s main page, bypassing the Bazar and the community, aka unfair competition - since years at large scale.
  • plasticpreneur - Whilst the molds seem ok, the machines are clearly overpriced for what it is. The often bold claims don’t match the facts. Locknuts on the shredder get loose or spring-loaded levers did hurt users. We would have expected to see more actual contributions with that high-profit margins but after all, another copy-cat milking you. Check yourself how clumsy and dangerous this stuff is.

Trusted and recommended providers

  • JW-Machines, aka ‘Morren Trading’. He’s a real machinist, working for a long time in the industry and delivered every time impeccably and well-thought-through designs at unbeatable price/value ratio, unlike any others we’ve seen so far.
  • BMH Solution, long around with industrial background, thumbs up for delivering a good value at decent prices.


Recently added

JARVIS Pro Shredder - Professional plastic shredder - 10000 Euro


Remarks: We know QiTech for a while but considering they’re very early adopters, very young and this is a rendering only without proven tests whatsoever, please consider the device from 3devo instead, starting at 7500 Euro - with shredder included. For 10000 Euro you can get a proper grinder and a massive shredder, and an extruder altogether. And judging by the other pictures, blade configuration and layout leaves much to desire.

Recently added

Shredder Mini - Handcranked Shredder

Here is another proof that Rory, from ‘Sustainable Design Studio’ lacks experience and skills, claiming ‘High Quality’ whilst having literally no equipment to do so.

  • Blade configuration makes no sense (no offset),
  • chamber walls way to big
  • hand-crank interface incomplete
  • impossible to make for 250 Euro, especially in the UK
  • no safety or hopper
  • no mentioning that you have to re-shred up to 15 times to get acceptable granulate
  • missing an appropriate hand crank (100- 150e in materials and fabrication alone)

Recently added


Attention here, the vendor claims 280C maximum operating temperature which is plain insane considering it’s using a mild steel barrel. The barrel would expand significantly at this temperature, creating a significant clearance to the plunger, and thus, plastic will be stuck at walls, creating extra friction but that is also abrasive, in return, the plunger will wear out a lot faster, and thus, the machine is more difficult to operate over time.

It also claims to support PETG which could be possible but would ruin the machine even faster. It requires 250C + to melt PETG. Till today, every request for any proof has been ignored.

We also doubt that this machine is using a bronze or brass plunger tip. This requires proper machining and we know, Rory @ Sustainable Design Studio doesn’t have this sort of equipment.

Once again, we recommend other providers with accurate and correct specs.