I recently picked up a heap of Quatro blocks, and noticed that the plastic seems to be much softer than the normal ABS-based Lego and Duplo blocks. Does anyone know what kind of plastic was used in these blocks?

  • Just wondering, does this also exclude Duplo and other Lego brick-like products? Note that Quatro are a LEGO product (albeit discontinued), and they are compatible with Duplo (and indirectly to Lego bricks). It seems to meet the criteria outlined in this question. Commented Sep 13, 2014 at 5:35
  • Also note that there is a dedicated Quatro page at brickset.com: brickset.com/sets/theme-Quatro Commented Sep 13, 2014 at 5:43
  • You are absolutely right. I mistook Quatro as a non-LEGO brand and I apologise. I have re-opened your question and if it is any consolation I have placed a bounty on your question in the hope that you will get an answer.
    – Ambo100
    Commented Sep 13, 2014 at 18:49
  • No worries! I don't think Quatro were very popular :) Commented Sep 14, 2014 at 0:40
  • I don't have an exact answer for you, but if you are willing to perform a little destructive testing, you can probably get your answer. This page (boedeker.com/burntest.htm) explains how to determine a type of plastic based on burning/melting it.
    – Nick2253
    Commented Sep 19, 2014 at 21:05

1 Answer 1


If it is intended to mate with other LEGO products, it is ABS. Just tweaked to be more elastic. Any discussion of materials published by LEGO always says LEGO and Duplo are ABS, with some SBS for tires and rubbery things.

There is some sort of polycarbonate used for the clear pieces, but these are rare, and they don't mate well with each-other, so LEGO actually tries to limit these in production kits.

I can't find a specific statement to this effect, but Quatro is almost certainly some tweaked ABS recipe, if only because they have to mate with other ABS pieces, and the tolerances are very tight for LEGO. Mixing plastics would be tricky (as it is for the PC pieces). Additionally, getting the colours just right so they match the colours in the other sets would be a nightmare if it was anything other than ABS.

  • The compatibility is actually not very good. Everything fits, but the softness of the Quatro makes it all a bit too loose to build anything useful. All very useful info though, thanks. Commented Sep 14, 2014 at 0:27
  • One of the design choices for LEGO is that the pieces have to mate well, but never too well. So, they will err on the side of easier to pry apart. This is going to be more of an issue for their sets intended for younger players. I suspect colour mating is probably more of a concern for LEGO when introducing related brands, and this speaks to using the same material processes.
    – user3971
    Commented Sep 14, 2014 at 0:29
  • Actually the colors are not very good either! I've sent an email to Lego, maybe they will find someone who can say? Commented Sep 14, 2014 at 0:42
  • Ah, this is an indication of how much they might have had to change the recipe. I still weakly maintain that it is ABS, if only because this plastic has well-known qualities and is very very stable. But I look forward to any confirmation.
    – user3971
    Commented Sep 15, 2014 at 15:47
  • 1
    Someone from Lego got back to me and confirmed that they do use ABS. I never would have thought! Thanks greatly for the additional info. Commented Sep 25, 2014 at 23:20

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