As I've just learned, LEGO bricks are made from ABS plastics.

I wonder if it would be possible to make some simple molds at home, get some ABS pellets, melt them up and make your own custom bricks? Novelty shapes or colours, perhaps?

Has anyone tried this, did it work?

  • Sounds like an awesome idea! Oct 26, 2011 at 15:37
  • 2
    Completely feasible, all you need is the equipment and you're good to go!
    – fredley
    Oct 26, 2011 at 15:41
  • 1
    Nice question. I cast a lot with resin in RTV molds but I would like to know more about ABS casting (tips and tricks).
    – pcantin
    Oct 26, 2011 at 15:53
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    Apart from those fans who contracted professional molds for new parts, no. Some have made milled, not molded, parts. This question might be too open ended. For one, it is feasible if you have lots of money, but
    – Erik Olson
    Oct 26, 2011 at 16:09
  • This question might be too open ended. For one, it is feasible if you have lots of money, so an answerable question could be Has anybody made a custom part using hobbyist equipment? Also Bricks is really too vague; it's very hard to make a brick, much harder than a sword or a gun.
    – Erik Olson
    Oct 26, 2011 at 16:15

4 Answers 4


People with 3d printers have made their own LEGO bricks. The plastic used is ABS.

Blog post

From makerbot.com

Interestingly, 3d printers can be constructed out of LEGO parts - you could have it self replicating!

Of course, you would need a very expensive and high quality printer to make good pieces. Cheaper ones can only make hollow bottoms and the banding from manufacture is highly visible.

  • Can you make your answer more specific? Bricks made on $ 100,000 printers interoperate with the real brick but sub $1000 printers produce bricks with poor tolerances.
    – Erik Olson
    Oct 26, 2011 at 18:41
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    LEGO itself uses 3D printers for prototyping, by the way.
    – Joubarc
    Oct 26, 2011 at 18:47
  • 1
    Ah, yes – of course. There's little you can't do with 3D printers :)
    – mikl
    Oct 27, 2011 at 17:45
  • @Joubarc, reference? Not that I don't believe you, but it'd be cool to read about.
    – Kyralessa
    Dec 30, 2013 at 19:37
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    Well, nothing a good search can't handle, apparently... here you go: LEGO Turns Design Concepts into Working Prototypes using Objet 3D Printer - the video provided by LEGO is very interesting.
    – Joubarc
    Dec 31, 2013 at 9:25

Big Ben Bricks sells some custom LEGO-compatible elements, mostly train wheels. Since they produce sizes which the LEGO company doesn't, they have some customer, but the production cost is usually quite high for such a quality.

BrickForge does sell custom elements too, and so do BrickArms. Usually, custom element producer will focus on elements the LEGO company is not likely to make, either because they feel the element fills too small a niche, or because they don't want to (arms). Yet there is some demand, so these sites aim to fill the gap.

If you've got ideas, maybe contacting one of those would be interesting, either to learn about their processes, or to suggest the part.

  • 1
    This came in as I was typing the same answer and content! +1 for prescience.
    – Nathan
    Oct 26, 2011 at 18:52
  • I'm surprised it didn't happen in the other direction, I'm usually quite a slow typist. Cheers, you'll beat me next time :-)
    – Joubarc
    Oct 26, 2011 at 18:54

Yes, is it definitly possible. However, as this page states:

Producing physical prints from our provided 3D models prompts certain fabrication considerations. According to Wikipedia, the precision of Lego pieces is less than 10 microns. As of early 2012, however, standard Makerbot printers have an XY resolution of 100 microns (0.1mm) and a default layer thickness of 360 microns (0.36mm). We thus caution that fabrication of the Free Universal Construction Kit with current (2012-era) solutions for DIY stereolithography, such as the Makerbot, Printrbot or RepRap, may lack the precision required for reliable or satisfactory coupling with standard commercial pieces. A great deal depends on how well-tuned the printer is; thus, your mileage may vary. In any case, we expect this situation will improve gradually, but inexorably, in tandem with improvements to these vibrantly evolving fabrication platforms. The artist’s proof shown here was created in a UV-cured white resin using a commercial-grade Objet (“polyjet”) 3D printer, which has a horizontal resolution of 42 microns, and a layer thickness of 16 microns. Ponoko.com and other private fabrication services offer printing from Objet machines and other high-resolution devices.

Free Art and Technology [F.A.T.] Lab and Sy-Lab. “The Free Universal Construction Kit.” Fffff.at, 20 March 2012. http://fffff.at/free-universal-construction-kit.

The article cited deals with a universal construction kit that allows you to connect ten diffent types of construction sets together, and as this is a Lego site, you may not want to visit it.

However, the point being that "standard" 3D printers (such as the Makerbot or RepRap) will probably lack the precision to produce tolerable Lego bricks.

  • 1
    We do acknowledge the existence of other building block toys here ;) Mar 21, 2012 at 19:20
  • 1
    @Zhaph-BenDuguid: Construction sets, as in, K'Nex and Tinkertoys.
    – fouric
    Mar 23, 2012 at 0:07
  • True yes we do consider those pretty much off topic ;) however that doesn't stop us looking... Mar 23, 2012 at 1:10

Here is a UV printer that can print on the Lego brick, see this link. https://www.youtube.com/watch?v=3OD2DCCpe2U&t=15s

And I think this A3 UV printer is good choice. http://www.wayprinter.com/uv-flatbed-printer/XP600-Epson-uv-printer-XP600sUV.html

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