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How to PREVENT Lego discolouring.


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#1 Callum

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Posted 26 December 2009 - 03:26 AM

Hi all, I have searched far and wide for handy tips on this topic but generally I only find information on how to reverse the effects (with varying results)

Heres what I plan on doing.
Building a wood and glass display cabinet to display my minifigure collection (I have several thousand, so turning yellowish would be a heart breaker!)
Now, I have access to UV protective archive glass.... would this solve the Yellowing / discolouring of Lego? does any one know for sure? (No guesses - my collection would be very upset!)
As UV Protective glass has a darker hue, I would likely have to install lighting inside of the case. I would imagine LED lights would be the best way to do this, or Cold Cathode... any idea if these will cause any discolouration too?
For a scale I are talking 3000+ Minifigures in a glass case (or two)

This will NOT be in direct sunlight, however I dont live in a cave (any more). I have some minifigures that have lasted 20 years without discolouring but they were locked in a box, and that seems hardly fun. Ideally I would like the display to last me out and still show no yellowing if at all possible. If it is not possible the collection will ultimately remain in its box. Unloved... alone....

Cheers all for your help!

Callum.

#2 Captain Zuloo

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Posted 26 December 2009 - 03:53 AM

My best suggestion would be test it. Put your LEGO (a small amount) in the oven at a low temperature to see if it discoulours. This is what The LEGO Group do when designing new sets. They place sets in an oven to replicate many years in sunlight to see how it discolours and which bricks fall off first and need to be stronger.
That wouldn't teach you anything about your glass though, so I would suggest modifying the LEGO method and testing it out on a small scale with lights rather than an oven. I would also magnify the light intensity to replicate many years of sunlight and see what the results are.

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#3 Callum

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Posted 26 December 2009 - 04:18 AM

View PostCaptain Zuloo, on Dec 26 2009, 04:53 PM, said:

My best suggestion would be test it. Put your LEGO (a small amount) in the oven at a low temperature to see if it discoulours. This is what The LEGO Group do when designing new sets. They place sets in an oven to replicate many years in sunlight to see how it discolours and which bricks fall off first and need to be stronger.
That wouldn't teach you anything about your glass though, so I would suggest modifying the LEGO method and testing it out on a small scale with lights rather than an oven. I would also magnify the light intensity to replicate many years of sunlight and see what the results are.

Mmm. I did contemplate this but working out what lights would be best to replicate the sun with was an issue (UV light for instance is not emitted from all sources, and in varying amounts from others)  

Also, the heat test suggests that it is the warmth of the sun that causes the bricks to discolour rather than the actual light. (Unless I am mistaken, UV is not produced by ovens!) So maybe I need a beer fridge!  :tongue:

Cheers for your reply :)
Callum

#4 CP5670

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Posted 26 December 2009 - 05:30 AM

I simply keep the blinds down in the rooms containing my Lego. That has worked well for about 8 years now (many of the sets are much older than that, but I've owned and had them on display for that long), with no noticeable yellowing on white pieces. The incandescent lighting I use in these rooms seems to have no effect on Lego.

The one exception to this is the type of pieces I talk about here (look under "oxygen sensitive white bricks"). There are certain pieces that will discolor quite noticeably regardless of the ambient lighting. Depending on what time periods your bricks are from, this may or may not be an issue. I have some 8880 wheels that have become strongly yellowed even in a completely dark box. I intend to try the bleaching techniques that people have discussed on them.

Edited by CP5670, 26 December 2009 - 05:31 AM.


#5 Callum

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Posted 26 December 2009 - 08:10 AM

View PostCP5670, on Dec 26 2009, 06:30 PM, said:

I simply keep the blinds down in the rooms containing my Lego. That has worked well for about 8 years now (many of the sets are much older than that, but I've owned and had them on display for that long), with no noticeable yellowing on white pieces. The incandescent lighting I use in these rooms seems to have no effect on Lego.

The one exception to this is the type of pieces I talk about here (look under "oxygen sensitive white bricks"). There are certain pieces that will discolor quite noticeably regardless of the ambient lighting. Depending on what time periods your bricks are from, this may or may not be an issue. I have some 8880 wheels that have become strongly yellowed even in a completely dark box. I intend to try the bleaching techniques that people have discussed on them.

I read your posts before starting this topic. I also have the 8880 with yellow wheels that went that way when sitting in the shade.

To further that I have some Horses from the castle sets that did the same thing , but only the Head or Torso has done it, or half a torso down the seam.  (so definately something weird in some batches of plastic)

Lastly I have the space shuttle (technics) that has some bricks that have yellowed but not others. The one I still have MISB has shown no signs of yellowing even though the bags have air holes.

Thanks for your reply :) keeping the blinds pulled is something I would rather avoid but if its the only option....

#6 brickzone

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Posted 26 December 2009 - 11:33 AM

I think at this stage a lot of my Lego is recent, and despite people's quibbles about colour consistency, I like the new brighter colours (even if they do verge on a bit of translucency) and for white in particular. The colour difference seems to match the new softer plastic and I am sincerely hoping these new parts don't have the same yellowing problem. If they don't, I would put up with the current colour inconsistency for all time just not to ever again have "tan" white pieces (I have some old white bricks that on one side are almost a match for tan).

I try to avoid having my light colours in particular exposed to much sunlight (curtains closed when not in the room, and they live in a darker corner) and that's about all I can do. I can't worry about oxygen exposure, and I cannot go without displaying models (although again, not in a window or such). Fortunately (in one sense) here in Ireland strong sunlight isn't very common - even in summer (this year we mostly had to put up with torrential downpours rather than sunshine - for those in the US, I believe Seattle/Washington State is similar weather to here, albeit slightly more continental).

When I have more space/money, my next storage/display problem would not be to tackle yellowing, but rather tackle dust. It is the current bane of my Lego displaying. I currently rely on a soft paintbrush (not that cheap actually) to gently dust off the models from time to time. This doesn't work if the dust is at all greasy - so only good usually for newish Lego or models not in a combined kitchen/dining room - and cobwebs are also a menace.

#7 Front

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Posted 26 December 2009 - 03:03 PM

View PostCaptain Zuloo, on Dec 26 2009, 04:53 AM, said:

My best suggestion would be test it. Put your LEGO (a small amount) in the oven at a low temperature to see if it discoulours. This is what The LEGO Group do when designing new sets. They place sets in an oven to replicate many years in sunlight to see how it discolours and which bricks fall off first and need to be stronger.
That wouldn't teach you anything about your glass though, so I would suggest modifying the LEGO method and testing it out on a small scale with lights rather than an oven. I would also magnify the light intensity to replicate many years of sunlight and see what the results are.

Heat test in an oven accelerates creep in the materials that may be seen in normal use over several years if the set is placed up in a window where the sun will heat it.
This has nothing to do with discoloration at all.
To accelerate the discoloration of plastic in a test, strong UV light is needed.

Creep in a material is permanent elongation due to stress below the normal 0.2 % stress limit. The amount of creep is dependent on material, duration, stress, and temperature.

#8 Legoliner Pilot

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Posted 26 December 2009 - 05:25 PM

View PostFront, on Dec 26 2009, 03:03 PM, said:

Heat test in an oven accelerates creep in the materials that may be seen in normal use over several years if the set is placed up in a window where the sun will heat it.
This has nothing to do with discoloration at all.
To accelerate the discoloration of plastic in a test, strong UV light is needed.

Creep in a material is permanent elongation due to stress below the normal 0.2 % stress limit. The amount of creep is dependent on material, duration, stress, and temperature.

Front, since you work with LEGO, I have to ask you a question. Which of the following results in LEGO parts yellowing faster: oxygen exposure or sunlight?

#9 Front

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Posted 26 December 2009 - 05:55 PM

View PostLegoliner Pilot, on Dec 26 2009, 06:25 PM, said:

Front, since you work with LEGO, I have to ask you a question. Which of the following results in LEGO parts yellowing faster: oxygen exposure or sunlight?

I am in no way an expert on plastic materials and only know the basics about the materials Lego use. What I may know the least about is actually something like changes to colors during the lifetime of a brick.  So I can't answer your question about which effects sunlight and oxygen have.

I am more interested in the mechanical properties of the materials we use, and how to select the right material for a new element. Things like safety, building functions, and strength are to be considered when selecting a material. In Bionicle and similar themes, we probably use a wider range of materials, compared to System themes. That is in no way to cut down material costs (which I often see speculations about here on EB), but because a material has to meet demands like safety and strength. A lot of Bionicle elements can't be made in ABS and at the same time satisfy the safety requirements for the product.

#10 CP5670

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Posted 26 December 2009 - 06:21 PM

Quote

I read your posts before starting this topic. I also have the 8880 with yellow wheels that went that way when sitting in the shade.

To further that I have some Horses from the castle sets that did the same thing , but only the Head or Torso has done it, or half a torso down the seam. (so definately something weird in some batches of plastic)

Lastly I have the space shuttle (technics) that has some bricks that have yellowed but not others. The one I still have MISB has shown no signs of yellowing even though the bags have air holes.

Thanks for your reply :) keeping the blinds pulled is something I would rather avoid but if its the only option....

It does seem like there were some bad batches of plastic at the time. I haven't seen any meaningful pattern in which pieces are affected though. Like you said, in most sets only certain pieces have the issue. I have a few yellowed parts in 8480, but they are all made of non-ABS plastics (axle joiners, 1x5 Technic plates, etc.). On the other hand, my 8880s and 8839 contain normal bricks and plates with the same issue. In 8839, all four 1x8 white plates have the problem but nothing else does, and other, non-Technic sets I have from the same years contain white 1x8s that look fine.

Anyway, apart from these special pieces (which only came out around the early to mid 90s), I think it's fairly easy to avoid yellowing by just preventing direct sunlight on the bricks. Artificial, incandescent lighting poses no problem.

This article has been posted here before, but it's a good read on this whole issue.

#11 Big Cam

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Posted 26 December 2009 - 07:29 PM

I have oly ever experienced yellowing when bricks are left out in dierct sunlight, otherwise I have bricks from 1986 and none have ever shown any signs of yellowing.

#12 Callum

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Posted 27 December 2009 - 01:56 AM

Looks like I may have to do some tests myself! I wonder if I should take some lego men to an artificial tanning Salon and some UV protection... I might officially own the worlds first lego Minifigure with tanlines!

Callum.

#13 Milan

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Posted 27 December 2009 - 02:55 PM

I have white bricks from 1987 and they are all white, but they were never exposed to direct sunlight, they were all kept in closed space, as a sets or as a pile of parts.
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#14 green dewback

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Posted 27 December 2009 - 04:24 PM

My room had the curtains drawn almost all the time, and my glass cabinet have paper stuck onto the glass to block sunlight. The stormtroopers still yellowed inside so I sold them away before it got worst. I do regret selling them off, my precious babies.  :cry_sad:

#15 MAH4546

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Posted 28 December 2009 - 04:27 AM

My collection is mostly kept in a dimly lit, always-air conditioned room, and sets that I've had for 10+ years are still white as new.

#16 wilson3a10

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Posted 17 August 2013 - 03:38 AM

Hi,

I would like to know if spraying semigloss clear paint would reduce the chance of getting the white bricks to yellow. Would there be any other methods? Thanks a lot!

#17 Darth Dino

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Posted 17 August 2013 - 07:41 AM

Hi

do not paint them. Lego bricks are high precision parts. Even a thin paint film will make them bigger/wider and increase the clutch power massively. You can not use them anymore as normal bricks.

If you want to prevent your Legobricks from yellowing, keep them away from daylight/UV light.

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#18 antp

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Posted 17 August 2013 - 11:10 AM

And if they yellow, they can usually be reverted to white using peroxyde + oxyclean
cf http://www.eurobrick...=75#entry800639

#19 eurotrash

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Posted 17 August 2013 - 03:31 PM

I use my yellowing/smoke stained bricks (from Craiglist acquisitions)in my creations!  They're perfect for my skeevy streets.  http://www.eurobrick...showtopic=84426 , http://www.eurobrick...showtopic=85890

#20 LegoDrake

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Posted 21 August 2013 - 06:44 PM

View Postantp, on 17 August 2013 - 11:10 AM, said:

And if they yellow, they can usually be reverted to white using peroxyde + oxyclean
cf http://www.eurobrick...=75#entry800639
   Will this work with grey yellowed bricks or does it only work on white yellowed ones.
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#21 antp

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Posted 21 August 2013 - 06:52 PM

From comments and tests there, it seems to also work on grey and blue bricks.

#22 LegoDrake

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Posted 21 August 2013 - 07:12 PM

Thank you very much antp.

Edited by LegoDrake, 21 August 2013 - 07:14 PM.

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#23 Faefrost

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Posted 22 August 2013 - 03:55 AM

Most clear paints will not actually bond to regular ABS bricks. (Trans clear polycarbonate pieces are another matter and clear acrylic can be used to rehab them). The paint will make the bricks feel weird and just rub off.

The yellowing is ultimately caused by the flame retardant added to the plastic. The peroxide oxyclean trick will help, but really it is in the plastic itself, and will probably return.
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