Does humidity hurt Lego bricks in the long run?

[ks6349]

I know that temperature may hurt the bricks in the long run

if they are exposed to high temperature or sunlight for extended period of 

time.

But how about humidity?

I store my Lego sets in dark so temperature or sunlight is not an issue, but recently it's really getting wet the weather

 

 

[ks6349]

1 hour ago, GREG998 said:

I'd tend to say humidity has no impact on ABS, so no problem for lego parts.

But, even in dark, i've seen white parts yellowing (basically, half of my stock.....).

White parts yellowing in the dark?? What is the science behind??

[deraven]

5 hours ago, GREG998 said:

I think HEAT is responsible. I had white cars stocked in dark, never direct light, turned tan...

I believe it's a variety of factors, but certainly the biggest is likely to be composition of the bricks.  The amount and possibly type of fire retardant used throughout the years, for example, can cause difference amounts of yellowing or browning in Lego.  For instance, I recently pulled some assembled MOCs out of storage that were put together looking pristine and have obviously had the same exposure to light and heat, but a number of the bricks are drastically more discolored than others, even ones they're directly attached to on the same surface of the model.

[ks6349]

On 2/26/2020 at 6:49 PM, GREG998 said:

Same thing here. For the same light/heat exposure, some parts NEVER turn yellow, some turn litteraly tan.

could the bricks inside a unopened sealed box also get yellowing over some years? (Always put in dark)

[ks6349]

1 hour ago, GREG998 said:

With a properly SEALED box, perhaps no if the issue is Oxydization.

Properly sealed box? Wrapped it with cling wrap? 

I have done this to a several precious sets

[dr_spock]

High humidity/moisture could provide an environment for micro-organisms.  Some micro-organisms can break down polymers but synthetic plastics like ABS can take a very very long time.  I think the instruction booklets and boxes would be more at risk for mold growth under damp conditions.

 

From BASF antioxidant marketing info:

Organic materials react with molecular oxygen in a process called "autoxidation". Autoxidation is initiated by heat, light (high energy radiation), mechanical stress, catalyst residues, or reaction with impurities to form alkyl radicals. The free radical can, in turn, react and result in the degradation of the polymer.

Sounds like oxygen could be the bad guy joining up with free radicals and causing no good. 

 

 

[ks6349]

On 2/28/2020 at 2:30 AM, dr_spock said:

High humidity/moisture could provide an environment for micro-organisms.  Some micro-organisms can break down polymers but synthetic plastics like ABS can take a very very long time.  I think the instruction booklets and boxes would be more at risk for mold growth under damp conditions.

 

From BASF antioxidant marketing info:

Organic materials react with molecular oxygen in a process called "autoxidation". Autoxidation is initiated by heat, light (high energy radiation), mechanical stress, catalyst residues, or reaction with impurities to form alkyl radicals. The free radical can, in turn, react and result in the degradation of the polymer.

Sounds like oxygen could be the bad guy joining up with free radicals and causing no good. 

 

 

A few months I bought a small lego set from a local personal seller it was a set in early 90s but it still like new..... when he sold to me it was still sealed and unopened.... I think it would take a lifetime to really do some oxidization do you think so??

Edited February 29, 2020 by ks6349

[MasterTyvokka]

A bit of a disclaimer before I continue. I am not an expert in plastics but I come from the action figure collecting world and in particular the Star Wars figures from the 70s and 80s, so my knowledge comes from that experience. There are a number of things that can cause degradation in plastics: temperature, exposure to UV, and yes, humidity. Those are the big three. But sealing your Legos inside an air tight container is not a perfect solution either because plastics off gas, even old plastics. This off gassing can potentially cause degradation as well. The ideal situation is to have everything displayed in room that has the windows blacked out and is climate controlled that way everything can breathe and there is limited UV exposure. Obviously this isn't practical for everyone. When I stored my action figures for a time I used acid free bags (ideally any storage device you use, that is directly touching the Legos, should be acid free) with holes punched in them and then kept them plastic bins with some drilled holes. I am not as concerned about my Legos as my SW action figures.

The thing is though, even under perfect conditions, plastic will still degrade. Different types of plastics will degrade at different rates (ABS seems to degrade slower than some of the PVC based plastic used in action figures) and you could even have two seemingly identical ABS Lego pieces kept under the same conditions degrade at different rates.

Also, I think ABS is less susceptible to the off gassing issues than PVC based on personal experience with my action figures. The PVC parts can get a sticky and I haven't noticed that to quite the same degree with ABS.