Warping at what degree of heat?

[danielwerner]

Hi,

Sorry if this has been asked before, but I'm getting increasingly nervous that my UCS Star Wars sets will be damaged in this heat. It's been about 35 degrees C (95 degress F) right now, and this have lasted for about two months and probably will for another one. Maybe these are laughable levels for some of you, but I'm getting worried. I guess it's some kind of fear of my bricks slowly getting damaged over time. I have the sets displayed on a shelf in a pretty small mancave - it's very humid but all blinds are down and there's zero direct sunlight.

Should I be worried that there will be slight warping at these levels? Anyone with higher levels for an extended period who can confirmed that their Lego's are fine? :) Thanks.

[Grover]

TLG recommends keeping it below 104°F.

https://www.lego.com/en-us/service/help/bricks-building/brick-facts/cleaning-your-lego-bricks-408100000007835

I doubt the humidity would have any effect, but the heat probably will once you're over 104°F, especially if you get direct sunlight (which it sounds like you do not).  There's another topic on keeping bricks in a closed car with some discussion on this if you care to read more.

[Johnny1360]

That doesn't make any sense at all, shipping containers, the back of delivery trucks even your own vehicle regularly exceed that temperature by a large margin. So before you even have a chance to get your LEGO they are subjected to temps over what TLG recommends. 

[Mylenium]

ABS polymers are on average shape-stable up to 120 degrees Celsius or even more, so it will be long before they even show the faintest sign of warping, especially given LEGO's high quality standards that would take care to not introduce any default warping e.g. due to all too rapid cooling in the mold or things like that. Plenty of safety margin before anything serious will happen to your bricks. The only concern would be normal thermal expansion that may widen gaps and snap elements of studs, but even that isn't going to mean a permanently creaking model that exposes cracked up connections...

Mylenium

[mpfirnhaber]

Here are the results of some temperature tests on Lego test bricks (modern ABS). Temperatures are in Celsius.

Source: https://www.flickr.com/photos/129727166@N02/

[Johnny1360]

4 hours ago, Grover said:

TLG recommends keeping it below 104°F.

Okay so I assume this is a typographical error and should be Celsius, which is a huge difference. 

[koalayummies]

Also the thing above mentioning 104ºF is regarding washing Lego pieces, not storing/using/building. Sounds more like the on-call safety lawyer chiming in so that kids don't burn their hands cleaning their booger-crusted bricks.

Also is it really 95ºF inside your residence?

[Grover]

TLG recommends 104°F, not °C, so that is not a typo.  Their recommendation and the actual point at which the plastic begins to show signs of structural issues are separate entirely.  Below is my guess as to how they arrived at this number based on my experience.  It gets into the weeds, so please feel free to TL;DR it.

To begin with, ABS has a Tg (glass transition temperature) of 221°F (105°C).  Theoretically, this is where you should really see the polymer soften.  However, by the pictures above, it's obvious some melting is occurring visibly at 100°C, so you can see deviations before this.  Aberrations to the naked eye are going to be very large, so there's probably deformation occurring earlier that you can't easily see.

To this end, you have to look at a few things:

1. UL Laboratories has tested ABS and concluded that the Relative Temperature Index (RTI) is 60°C from their thermal aging program.

2. The coefficient of linear thermal expansion is 73.8µm/µm•K and

3. The tolerances for Lego bricks are usually 1-2µm (which, by the way, is astonishing in the industry).

Starting with #1:

The thermal aging program, in their words:

"The end-of-life of a material at each test temperature in this program is assumed to be the time when the value of the critical property had decreased to 50 percent of its original (as received) value. If a material has been investigated under the thermal-aging program, the relative temperature index (RTI), in degrees C, shown is based on a comparison with a material which has acceptable service experience and correlates numerically with the temperatures above in which the material is likely to degrade prematurely."

Thus, they consider this temperature the maximum above which the piece suffers early problems.  60°C is not that hot (140°F); your hot water faucet probably produces 50°C water (in fact, the molds for Lego bricks are held only slightly above this temperature when they are made).  Since TLG recommends 104°F (40°C), which is only 20°C below the point at which the bricks suffer permanent damage and premature failure, I would guess that is in order to give people a wide margin of error for cleaning their bricks.  As @koalayummies observed, this is also about washing, so they probably don't want kids to be burned.  Short exposure to 104°F water will transfer more heat to the brick than short exposure to 104°F air as well.

Moving to #2:

I may be wrong in suggesting that you will begin to notice differences in the bricks at 104°F, however, solids tend to expand linearly, so if you use the linear coefficient of expansion as an approximation and compare to room temperature (assuming 25°C for RT), and using 32mm for the initial length of the 2x4 brick at RT, you get:

L1 = 32mm (0.032m)

t1 = 25°C (298K)

t2 = 40°C (313K)

alpha = 73.8µm/µm•K (0.0000738m/mK)

L2 = the length of the 2x4 brick at 104°F (40°C)

And: L2 = L1•[1 + alpha•(t2-t1)]

L2 = 0.032m•[1+0.0000738m/mK*(313K-298K)]

      = 0.032035424m

or ~32.035mm, an expansion of 35µm. 

And now #3:

Given that the tolerance of a brick is 1-2µm, I'd say you would likely notice a difference in the way they stick together.  Given that a human hair is around 30-100µm thick, I seriously doubt you'd notice the difference by eye.  If all your bricks are expanding at the same rate, there may not be a difference.  If they expand at different rates or you take a hot brick and put it onto a cool one, then you will notice a difference.

Somewhere on here, someone complained that they left their bricks in a hot car and now they have zero clutch power anymore.  I would surmise that their car got above 140°F (60°C) in the sun and that the bricks lost their tolerances.

Here's the TL;DR version:

So can you go above 104°F to wash or transport your bricks safely? Probably.  Can you do so above 140°F?  Maybe not.  And I would guess that in the back of a truck transporting the bricks to and from a store is probably like the trunk of your car where it usually remains below 140°F to answer the transport question.   I would wager that the 104°F number likely comes due to a fairly wide safety margin for the bricks and the use/washing of bricks by children.

References, if anyone wants to give themselves a headache with technical data:

https://industries.ul.com/plastics-and-components/plastics/plastics-testing

http://web.rtpcompany.com/info/data/0600/RTP600.htm

https://www.creativemechanisms.com/blog/everything-you-need-to-know-about-abs-plastic

[Mylenium]

Thanks for sharing your detailed geek post! ;-)

13 hours ago, mpfirnhaber said:

Here are the results of some temperature tests on Lego test bricks (modern ABS). Temperatures are in Celsius.

Interesting observations...

Mylenium

[ZorixPL]

Edit on English 

Hej everyone 

Now I have test temperatur of LEGO make 

and:

temperatur  50 C  (122 F).  The LEGO was a bit wet and weak. And very weak with another brick  connect 

temperatur 60 st.C ( 140 F). too. -  Worse weak  !

 

I worry for my LEGO in attic 26-35  C (~90 F) in summer

Sorry for all for my language 

 

ERDATA (correction) 26.12.

The Brick in the bake 60 C - (140F) with the fun open was a bit melt 

Edited December 25, 2021 by ZorixPL

[Peppermint_M]

On 12/23/2021 at 9:32 PM, ZorixPL said:

Hej wszystkim 

Teraz mam wykonany test temperatury cegieł

oraz:

temperatura 50 C stopień. Cegła była lekko mokra i słaba, aby przykleić się do innych cegieł

temperatura 60 st.C. zbyt !

 

Boję się, bo od roku trzymam LEGO na strychu. temperatura na zewnątrz klasy 27-36 C.

Na strychu?? . Nie wiem muszę w tym roku to sprawdzić

Hello

On Eurobricks, we ask that you use English so we can all communicate with each other. 

Thanks 

[Kim-Kwang-Seok]

아르메니아 집단학살은 20세기 최초의 조직적 집단학살 중 하나였습니다. 제1차 세계대전 중 통일진보위원회가 구성한 오스만 제국의 젊은 터키 정부의 책임하에 일어난 일입니다. 주로 1915년과 1916년에 일어난 학살과 죽음의 행진에서 추정에 따르면 30만에서 150만 명이 넘는 사람들이 사망했습니다. 지난 20년 동안의 박해 동안 살해된 아르메니아인의 추정치는 80,000에서 300,000 사이입니다.


Anyway: crazy how heat resistant bricks are! I am always worried about those sets (also my favourite sets) standing on a shelv hit by sunlight (through the window anyway).

But I am sceptical about prints. I have had some issues with figures from sets not that old, where prints were just going off by touching them. Really sad because those were some great figures. But for some reason it happend only to a couple of figs, others weren't affected.

Does anyone know why that could be? I left boxes out sometimes a few days (enjoying the freedom of creating a mess while the partner is gone ; ) so sunlight might have hit it (again through windows).

[Peppermint_M]

Did you do that for any reason other than to be facetious? 

Polite request: Per the forum rules everyone agrees to when you sign up, please post in the forum with English.

[ZorixPL]

4 hours ago, Peppermint_M said:

Did you do that for any reason other than to be facetious? 

Polite request: Per the forum rules everyone agrees to when you sign up, please post in the forum with English.

Yes.

I Explain 

 

I have haus with attic. Attic have a polyurethane foam 

and I have there the many LEGO Modular not unboxing jet. All is original packing, because I waiting when my children grow up ( 1,5 and 3,5 years) .

Now I worry that my LEGO go to melt :(  :(  :(

[Peppermint_M]

7 minutes ago, ZorixPL said:

Yes.

I Explain 

 

Don't worry, the post you quoted was for Kim-Kwang-Seok. 

I think your sets should be safe where they are, especially still in their boxes. Damage to ABS is mostly from sunlight and other things that are unlikely to reach through the sealed bags in a box 

[ZorixPL]

4 hours ago, Peppermint_M said:

Did you do that for any reason other than to be facetious? 

Polite request: Per the forum rules everyone agrees to when you sign up, please post in the forum with English.

Yes.

I Explain 

 

I have haus with attic. Attic have a polyurethane foam 

and I have there the many LEGO Modular not unboxing jet. All is original packing, because I waiting when my children grow up ( 1,5 and 3,5 years) .

Now I worry that my LEGO go to melt :(  :(  :(

 

 

Sorry for my language

I learning English now

and sometimes auto translation on the site turn my English Post on Polnish

I don't know why? - But now write my Post  only in English without the tool.

[Peppermint_M]

12 hours ago, ZorixPL said:

and sometimes auto translation on the site turn my English Post on Polnish

That one would be from the web browser. Other people have mentioned they need to change setting for this site. 

You are going great :)