6x6 radar dish-.LEGO plastic quality

gelkster

I'm lightening my white pieces in hydrogen peroxide  (works GREAT BTW) but I have a 6x6 solid studded radar dish with a bad case of yellowing, it's almost tan. However the H2O2 doesn't seem to help it. A friend suggests it may be of a different quality plastic, but did LEGO ever NOT use quality ABS plastic after 2010?

I've got the dish pinned down to sets from 2013, its type appeared in several Xmas ornament sets around that time but I think it's from City: Space Center.

MAGNINOMINISUMBRA

Post 2010 White is problematic at best, shocking at worst!  I've opened several post 2010 sets where new white bricks are actually cream colored rather than any shade of white on a colour chart. 

davee123

gelkster said:

did LEGO ever NOT use quality ABS plastic after 2010?

I hate to say "quality", because there are many different aspects to ABS plastic in terms of its color fastness, likelihood of breaking, maintaining clutch power, etc.  However, I believe in general LEGO's ABS quality has essentially gone down, not up, since maybe the late 1990s?

Starting around 1998-2000 (ish), LEGO plastic seemed to be slightly more "mooshy", possibly to help younger kids put bricks together more easily?  That's based on a few personal experiences as well as a few things I've heard second-hand (including one related directly from a Master Model Builder), but nothing official.  I don't know if you'd consider that a "quality" change per se, but it seemed to affect the ABS.

In about 2006-2007, LEGO started using dye injection to color their ABS bricks, rather than pre-colored ABS, but I'm not sure how many parts are colored this way, or how gradually it was introduced.

In 2009-2010 or so, some LEGO started getting made in China with a different mixture of ABS.  The supply company was reportedly the same, but there was a statement from LEGO that they had to use an in-country supplier of ABS, and couldn't bring in ABS from outside (possibly for legal reasons, it was never made clear).

Additionally (I don't know the timeframe), LEGO started using multiple suppliers for ABS rather than a single supplier, so that they could keep the raw material cost competitive-- but the difference in ABS quality between the suppliers I don't know.

When Jørgen Vig Knudstorp took over the company in late 2004, he very purposefully lowered quality in order to save money, so most of these changes I believe are a direct result of that.

They continue to try and fix problems that they have (I'm not sure what they've tried with respect to yellowing), and certainly some problems seem to have been alleviated-- so it's not like LEGO's abandoned quality all together or anything.  But their attitude now is to always balance quality against cost, which has overall seemed a bit detrimental to quality as compared to older levels.

As for ABS itself, it's very finicky.  So it's very common that some parts will yellow VERY differently from others-- and I wouldn't be surprised to learn that the hydrogen peroxide would work with varying levels of success depending on the specific batch of ABS as well as the type of element, and how it in particular has yellowed.

DaveE

CCC

davee123 said:

In about 2006-2007, LEGO started using dye injection to color their ABS bricks, rather than pre-colored ABS, but I'm not sure how many parts are colored this way, or how gradually it was introduced.

I don't think that is quite right - but it might just be down to words. LEGO would have used dye to colour the raw ABS molten polymer, rather than actually dyeing the bricks. That is, they would colour the ABS in melt, then form the bricks and not actually colour the bricks once they are formed. (I might just be misreading your words though.)

However, before that the ABS polymer would probably have also been dyed, just by the manufacturer rather than by LEGO. I'm fairly sure the pigments are normally added after the polymerisation for ABS. So the colour is added once the polymer has been formed, and not pre-coloured by adding the dye to the monomer mix before polymerisation. Thus the pre-coloured ABS used by LEGO would also have been dyed (pigments added). Just that it would have been dyed by the manufacturer and not by LEGO, and they may have been more consistent with colour.

And, of course, it may be that they have also changed suppliers of ABS (and as you note have different suppliers for China). ABS is not necessarily a consistent molecular ratio and also the rate of polymerisation and the resultant molecular weights and thus the physical properties generated can vary with processing.

I quite like the softer (your "mooshy") modern ABS.

davee123

CCC said:

I don't think that is quite right - but it might just be down to words. LEGO would have used dye to colour the raw ABS molten polymer, rather than actually dyeing the bricks.

Yes-- I didn't mean to imply that they inject the dye into the already-formed elements, sorry if it reads that way.  One question I WOULD have on that, though, is how close to the time of molding the dye gets added.  I assume there's a process to melt translucent granulate, which then flows into the mold, but I don't know how separated the dying process is.  Is it added in a separate process before the ABS is channeled into the mold, or is it done (say) further up the channel?  I'm not really familiar with that part of the process, but it'd be interesting to see (most of the explanations I've seen on LEGO molding seem to refer to pre-colored granulate)

CCC said:

Thus the pre-coloured ABS used by LEGO would also have been dyed (pigments added). Just that it would have been dyed by the manufacturer and not by LEGO, and they may have been more consistent with colour.

Yeah, this is where the above comes into play.  If the manufacturer is doing the dying, I would assume their process to be pretty consistent, but if LEGO's doing it, and especially if it's not very removed from the molding process itself, I would imagine that it would create a lot more inconsistency.  That's just speculation on my part, of course, but from the perspective of an outside observer, it certainly coincides with their inconsistencies in color, so it seems to make sense (though it could be due to some other factors that we haven't even been told about, of course).

CCC said:

I quite like the softer (your "mooshy") modern ABS.

I think both have their uses, although generally I like the harder stuff.  We worked alongside Master Model Builders for a project in 2004, and discussed having many large plates "sandwiched" together to build large roofs-- they kept slowly "mooshing" off of each other unless they were studded down all the way (for which we needed to use rubber mallets).  But my own experience with the same technique with bricks minted in 1995-1999 (just a guess) was that they did NOT moosh apart.

But on the flipside, the softer ABS is easier to work with, I think!

I often wonder whether or not it has anything to do with the "cracking" issue that we see, although I assume not.  I first observed cracking in parts in 2003, before the color change, but after the "mooshy" change, when I believe they were still pretty consistent with their ABS.

I was told once (from someone who worked in injection molding, but not for LEGO) that it was likely due to more vinyl being added to the ABS mixture, in order to make the plastic softer and more pliable.  But I don't know what other side effects that might have.

My assumption with the "cracking" bricks has always been that the "seams" where the injected plastic meets are likely where you'd see cracks develop, and perhaps these seams are more subject to separating depending on the consistency of the ABS being used-- thereby potentially being a side effect of something like added vinyl.  But again, I assume there are far more factors in play that might feed into that, so again, just speculation.

DaveE