Are helmets, arms, and air tanks made of different types of plastic? Any way to repair face printing?

[hagridshut]

One of my Ice Planet astronaut minifigs (white helmet, white arms, white air tank) has white arms that turned a light shade of yellow/pink/gray.  Oddly, the helmet and air tank are still pure white.  I am pretty sure these are the accessories that came with this minifig, and none of my other Ice Planet helmets or air tanks are discolored.  

Does anyone know if the plastic used for helmets and arms is different?  They seem to be the same smooth, hard plastic.  The air tank plastic seems softer and more flexible, but I'm not sure if that's because of a difference in manufacturing or a difference in the molecular structure of the plastic.  

The Ice Planet minifig in question also has a mouth that is partially worn.  Is there any way to restore the print?  At the moment, I intend to just leave as-is (if only to make identifying the individual figures more easy).

[1963maniac]

Just google "discolored Lego parts" and you'll find ways to bleach the color. 

[MAB]

Hands are definitely a different composition. If you try RIT dying torso assemblies, the torso and arms take the dye whereas hands do not.

I think also the airtanks and a number of other neck bracket molded pieces are different compositions, as they are flexible, as you say.

[Grover]

Most of the minis are ABS (acrylonitrile-butadiene-styrene).  Some parts that are more flexible (but not rubbery), like the trees, are polyethylene or polyproplyene.  I'm not entirely sure what they use for the hair that's very rubbery, but it may be SBS (styrene-butadiene-styrene), just a guess.  Fixing the face on a mini will likely require pad printing to do properly, which is impractical.  Otherwise it's hoping for a very steady hand with enamel and a tiny paintbrush (this usually looks like crap in my experience).  For the color change, look up the thread on yellowing in this forum.

Edited October 10, 2019 by Grover

[MAB]

I wouldn't bother de-yellowing white arms. They are so cheap, you might as well buy a new pair and replace them. Same with the head (if it is the male one). If the figure is worth $1 or so, it isn't really worth bothering with to repair it when it can be replaced instead. 

 

[hagridshut]

18 hours ago, Grover said:

Most of the minis are ABS (acrylonitrile-butadiene-styrene).  Some parts that are more flexible (but not rubbery), like the trees, are polyethylene or polyproplyene.  I'm not entirely sure what they use for the hair that's very rubbery, but it may be SBS (styrene-butadiene-styrene), just a guess.  Fixing the face on a mini will likely require pad printing to do properly, which is impractical.  Otherwise it's hoping for a very steady hand with enamel and a tiny paintbrush (this usually looks like crap in my experience).  For the color change, look up the thread on yellowing in this forum.

 

15 hours ago, MAB said:

I wouldn't bother de-yellowing white arms. They are so cheap, you might as well buy a new pair and replace them. Same with the head (if it is the male one). If the figure is worth $1 or so, it isn't really worth bothering with to repair it when it can be replaced instead. 

 

Yeah, I figure I'll just leave this Ice Planet minifigure as-is.  He works just fine anyways: arms and torso have no cracks, and legs still have the right amount of tension.  He's just a bit worn from decades of adventuring on planet Krysto and its solar system!

[Gomek]

On 10/10/2019 at 7:47 PM, hagridshut said:

Yeah, I figure I'll just leave this Ice Planet minifigure as-is.  He works just fine anyways: arms and torso have no cracks, and legs still have the right amount of tension.  He's just a bit worn from decades of adventuring on planet Krysto and its solar system!

It's funny, I have a few figures which really stick out of in my collection as being the few figures not in like-new condition. Those are the ones who's play-wear is well earned.