Sign in to follow this  
jd5775

Yellowing in MISB sets

Recommended Posts

Yes read that other thread, lots of info there. The one on Brickset Forum has good comments too, including some fairly controlled experiments by a Danish LUG. Search for "unyellowing" and you'll find the thread.

Mark Stafford said something interesting at AFOLCON 2012 in Manchester. If I remember correctly (which I don't always!) he suggested total darkness is not ideal for preventing yellowing and that translucent plastic containers are best.

Share this post


Link to post
Share on other sites

It's also, from what I've been told by LEGO insiders, dependant on the specific chemical mixture in any particular batch of bricks - some batches are more prone to discoloration than others. I've seen 10-15 year old MOCs built from a number of white bricks, obviously from different sets and probably different time periods, where some bricks look pretty much as white as they were when they first came out of the box, whereas others could not possibly be distinguished from a modern part in tan. And they had all been connected to the same bricks since the MOC was originally built - i.e. stored in the same place and exposed to the exact same conditions.

Share this post


Link to post
Share on other sites

It's also, from what I've been told by LEGO insiders, dependant on the specific chemical mixture in any particular batch of bricks - some batches are more prone to discoloration than others. I've seen 10-15 year old MOCs built from a number of white bricks, obviously from different sets and probably different time periods, where some bricks look pretty much as white as they were when they first came out of the box, whereas others could not possibly be distinguished from a modern part in tan. And they had all been connected to the same bricks since the MOC was originally built - i.e. stored in the same place and exposed to the exact same conditions.

The chances are this is something that Lego probably had limited control over. During that time period weren't they still fully using pre colored pellets from Bayer? I believe the Flame Retardent is added during plastic production, not simply melting for casting. And plastics companies were and are constantly tinkering with the additives. So it isn't so much what batch the bricks came from, as what batch of plastic each in turn came from. And figure there was even more variations as different batches of pellets were mixed. I'm thinking "color shift after 20 years" was probably not a key testing metric at the time.

Share this post


Link to post
Share on other sites

Another possible reason:

Your set might have been restored. Yellowing can be treated with Hydrogen Peroxide (H2O2), BUT depending on the cause of the yellowing (UV, smoke or BFR), the results may not last very long. I have treated sets that showed equally yellowed bricks. It looks like this is usually caused by the Bromine Flame Retardants breaking down (Bromine is brown). The results were impressive, but after a few months without any UV/Smoke exposure, the yellowing on white bricks came back and got even worse. I cannot recall having the same issue with other colors such as grey or blue...

If the blue bricks were also treated against yellowing, they might look slightly lighter than other blue bricks from the same period.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

  • Recently Browsing   0 members

    No registered users viewing this page.