White plastic wheels become brown

[stamatis]

Hi,

 

I recently noticed that all my white plastic wheels, after some time become yellow or brown,

esp. the section around them, where the tires are mounted.

 

Any idea why and any cure for that?

 

Stamatis

[racer1]

Pretty common problem. Some people have luck with soaking the parts in peroxide and placing them in the sun.  For some this restores the parts completely while other parts are too far gone to bring back.  If your wheels are too far gone I would suggest painting them then putting a clear coat in either gloss or semi gloss depending on the finish you want. 

[stamatis]

I ll give it a try...  Thanks!

[WillyChang]

Smoking household, polluted environment?

[waterbok]

Familiar problem not just with tires, sofar I was succesfull with some water.

[stamatis]

No smoke nor polluted enviroment.

Probably the rubber causes it, as it is only around them and not in the center.

 

Of course I got some even worse examples, like a set of white M-wheels that now are yellowish.

Rally Tamiya tires usually cause that.

[WillyChang]

Interesting.

In another hobby (I have too many, the wife says...) I too have come across rubber discolouring manmade polymers. Latex is vulcanised into rubber with sulphur... some elemental sulphur is trapped in the rubber and gases out over time.

This sulphur when in close contact with materials like celluloid or ebonite discolours it to a dark brown... might be similar process to the bromine chemical transformation that yellows white ABS plastics? (uhoh, crossover to Lego hobby)

The Lego fans been whitening old yellowed Lego by soaking in hydrogen peroxide and sunning it, similar to what we do with yellowed Tamiya plastics.

Or try chlorine bleach (sodium hypochlorite), shouldn't attack plastics & I use it to disinfect used Lego.

Both nonRC hobbies mentioned above involve objects that have been around for 60-70yrs though, not just 20. 

 

[stamatis]

Oh, that was a nice approach of my issue!

So it seems like an easy fix then!

Thanks!