Welcome To McDonald’s; Would You Like 3D Printing Resin With That?

University of Toronto researchers have succeeded in converting used cooking oil — from McDonald’s, no less — into high-resolution 3D printing resin. Your first response might be: “Why?”, but thinking about it there are several advantages. For one thing, waste oil is a real problem for the food industry, and thus it can be acquired rather cheaply. An even bigger benefit is that the plastic that originates from this oil is biodegradable. Their 3d-printed butterfly, of course, is made from the recycled resin.

We aren’t chemists, but apparently 3D resin has a lot in common with cooking oil already. The team used a one-step chemical process to convert one liter of McDonald’s greasiest into a little more than 400 milliliters of resin.

Conventional 3D printing resin derives from fossil fuels (as opposed to the renewable PLA often used in FDM printers), and takes multiple steps. This drives its cost up. The researchers think they can produce their resin for about $300 per metric ton.

The one thing that worried us was the biodegradability. They claim that a buried object lost about 20% of its weight in a week due to microbes eating the fat. We don’t know how long the pieces would last sitting up on your kitchen counter.

Resin printers are getting more common, even though they still aren’t as plentiful as fused filament fabrication. If you want to try one, be sure you know what you are getting into.

33 thoughts on “Welcome To McDonald’s; Would You Like 3D Printing Resin With That?

  1. the problem is not that there is nothing to do with the waste oil from these places as there are plenty of uses for it, it is more along the lines of the regulations that you have to go through to do anything with the waste oil once you acquire it for commercial use.

        1. Often they do not even convert it chemically. Normally “biodiesel” is made by conversion of the glycerin esters to methanol esters.
          I know people, who just filter it and put it into the tank.
          But probably there are different regulations in different states.

        2. No, not anymore.

          Nearly 20 years ago that was a thing. Used fryer oil was a waste that restaurants had to pay someone to haul away. Some people figured out they could run their cars off of it and the restaurants were happy to let them and save money on disposal fees.

          They shared this information on the internet.

          I don’t know what the oil is used for now. Perhaps it ends up at those few gas stations that sell biodiesel. Maybe the pick-up companies, who also own the containers are just protecting their own racket. I don’t know but apparently somebody did get the message that there was monetary value in that oil.

          Now, at least in my area all the fast food used-oil tanks have big signs on them stating that taking the oil is theft and violators will be prosecuted. Most have locks or even fences around them.

          I notice this when going through drive-throughs because “back in the day” I was pretty excited about the idea of free fuel and was considering buying a diesel car and attempting it.

          I’ve noticed the same thing at recycling stations. It used to be you could drive up to one and take all the boxes you want. That got me through several moves. Now they all have signs saying no taking, violators will be prosecuted and cameras everywhere.

          What jerks! It’s really too bad for the planet because re-use is way better for it than recycling. As for lost-pulp and profit for the recycling company.. well where did they think the boxes ended up after the move? Right back at the recycler of course! Besides, even if I kept them all I still dropped off far more paper and cardboard than I ever took.

          1. Wow. You bring up a wonderful point. The phrase is “Reduce, REUSE, Recycle.” These cats skip the reduce and reuse part of the process. They just take it and recycle it. That’s almost as bad as just not recycling. The energy required to recycle is often greater than just making something new. It just goes to show you money is behind everything. Nobody who has the power to change things really cares about Earth. They do what makes them fat and happy as long as it makes some San Francisco activists feel good while driving in their Tesla.

        3. In many jurisdiction it was always illegal to use cooking oil for road vehicles because you’re driving without having paid your road taxes. Chances of getting caught? Pretty low (unlike house heating diesel oil that has a chemical tracer additive to catch cheaters).

          But the practical reason is that putting used cooking oil into almost any post-2000 diesel vehicles will near-instantly destroy the fuel injection system with easily $3000-$5000 of repairs, which depending on vehicle age can total the vehicle.

          Old mechanical injector systems (eg: non-TDI-branded diesels VWs before around 1997) could tolerate well enough the amount of dissolved water in the oil and the tiny food particulates that still pass through most filters without oxidizing, jamming (open or closed), and/or sending metal shavings into the engine.

          You could probably still get away with it on a tiny diesel go-kart/dune-buggy if it has an old style mechanical injector pump, with a shot of injector cleaner every once in a while and flushing the lines with diesel before you stop the engine to prevent oxidation.

    1. yep here in the UK you used to be able to use waste oil streams for heating (in a suitable appliance) now that’s illegal (thanks EU, shame Brexit wasn’t sooner) so now I need to pay someone to truck my waste oil away to then get used in another incinerator for ,say, tarmac production. the lisencing and emissions fees make it cheaper for me to pay to have my oil taken away and pay again for diesel to run my heaters. madness. only really suitable for heavy industry. food oil is categorised as non-hazardous so can be used by a DIY type for biodiesel, but most restraints have to pay to truck it away.

      1. It is even more stupid than that. You can’t burn the waste oil in a purpose built device with sensors and catalysts in the exhaust but no one will bother if you soak newspaper in it and make bricks to burn on an open fire.

        Proper nuts it is.

      2. Good thing the evil EU thing is history for you guys now and you can revert your country to a proper pre-EU state and do whateeeeeeeeverrrrrr you want.
        And you soon CAN to whatever because you must be the richest country in Europe, now having an extra 350 million GBP to spend per week because you left the unholy union haha

        But back to the real topic. I wonder why you guys need to pay for disposal, as the UK seems to import huge ammounts of the stuff from around the world to make biodiesel: https://www.bbc.com/news/science-environment-48828490

        Now I’m interested, wow much do you need to pay for disposal of what ammounts?

        1. No it is to do with the EU


          IT used to be you applied to the council for a small waste oil burner permit, the council sent out someone to inspect your equipment and you pay the yearly fee (£120 ish) and your good to go.

          these were abolished as the uk had to follow the IED (A european directive)


          Now I am all for helping the environment, but if the oil is going to be burnt somewhere, surely its best being burnt at the source rather than transported and burnt (assuming similar emissions on both ends) as there is a net increase in emissions due to the transport.

          But yes this is a slightly different topic to the biofuel debate. Perhaps the US exports so much cause they produce an excess of ethanol from corn to produce E85 so have no interest in using waste oil streams.

      3. Hah! That’s funny! Don’t you know that the UK is mini USA? When the EU isn’t telling them what to do they will probably mandate that it all be dumped on baby seals or something.

  2. Reading the original article this sounds really like “we hardened chemically treated cooking oil” and that’s about it…
    It hardens further in sunlight and bacteria like to feast on it, and “it wouldn’t crumble or melt above room temperature.”. IMO this means that the stuff is barely usable and more like hardened cooking oil than any usable material…

    I’ve worked with the original Formlabs 1 printer and parts printed with their resins. Even those parts cured further in normal (sun)light to the extent that they got really really brittle quite fast.

  3. As there’s no edit function for posts, here’s what they did (the real paper is available here: https://pubs.acs.org/doi/abs/10.1021/acssuschemeng.9b06281)

    They took WCO (waste cooking oil), drained it through a filter and then acrylated it with Acrylic acid and boron trifluoride etherate. Cooking it, cleaning with hexane, etc follows.

    Then they add 1% Irgacure 819 as a photo-initiator to make it UV-curable by the printer.

    The bio-degradability is mentioned too: “This can be explained by the presence of bioavailable fat molecules (or microscopic food particles left over from cooking) in the AWCO prints which themselves can be rapidly biodegraded and in turn give better access of the polymer network.”

    Which they in turn idealize into eco-friendliness…

  4. All the places around here have no problem offloading waste cooking oil–lots of people convert it into bio-diesel. Too many in fact–some restaurants have started trying to charge for picking up their waste oil.

  5. I ran WVO (waste veggie oil) from restaurants as fuel in multiple diesels (converted to run on it) for over 5 years, until I moved and couldn’t find another source.

    The microbes can be an issue for this type of application, but they are easily dealt with. The issue is that the easiest solution negates the advantages of 3D printing, that being the rapid part of rapid prototyping.

    What we did to kill the microbes, after filtering and de-watering the WVO, was to pump the clean WVO into the same cubies (pronounced cube-ees) that we picked it up in, after we rinsed them out with clean WVO. Fill it to the top with as little air as possible.

    After about 3 weeks in the cubies, a darker layer will settle and form on the bottom. That layer is dead microbes. Killing the microbes made no difference on how the engine ran, but your filters last a little longer.

    If they had a much faster way to kill the microbes, rather than starving them of air over the course of 3 weeks, then the microbes issue could likely be largely mitigated.

    Here’s a link to the 35lb (15.87 KG) boxes we called cubies, it’s a plastic container inside a cardboard box. https://www.amazon.com/Admiration-Fry-n-fry-Canola-Liquid-Frying/dp/B00FLM8H3E/

    1. Here on Earth dihydrogen monoxide doesn’t really make a very good material for 3d printing. It comes out too thin and solidifies too slowly. It would be difficult to actually get it into a desired shape. It also expands a lot as it cools. No doubt it would make HDPE look like PLA when it comes to warping.

      But, at really really cold temperatures… and if you weren’t after any kind of detail on the scale we are accustomed to with plastic filament printers…

      Maybe you could use it to print houses on Titan.

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