Different Plastics used - why?

[tom mann]

I have two premium HO scale freight cars, both have a lot of nice detail and retailed for about the same price ($25). 

1.  The Kadee car's plastic detail pieces are nice and robust and are able to accept deflection without breaking.
2.  Another car (not naming manufacturer names) has pieces that are made out of a plastic that crumbles as parts are accidentally deflected.

Why isn't the first type of plastic used in both examples?   

[peteski]

Maybe because Kadee is US-made with quality plastic and the other car is molded in China using inferior plastic?  Maybe the brittle plastic is cheaper or the engineers who decided on which plastic to use didn't take onto consideration the fact that these items could be abused, so they decided to use brittle plastic?  Just speculating...

There are probably  many formulations of polystyrene or ABS plastic with more or less plasticizer added.  Pure polystyrene is very brittle and will shatter into glass-like shards.  The color of the plastic (dies and fillers added) will also contribute to its mechanical properties.

[Scottl]

As will it's age and exposure to UV, and air borne and liquid solvents.  Cheap or poorly formulated plastic is probably the number 1.

[Chris333]

Ask Dave Foxx.

[sizemore]

Ask Dave Foxx.

+1


The S.

[peteski]

I re-read the question and now I'm not sure if I answered it correctly.  I'm not familiar with Kadee H0 cars and their construction.   But I know that N scale MT cars have stirrups molded as separate parts, from Delrin.  Delrin is very flexible. But other manufacturers mold the body and stirrups as a single piece (ABS or styrene).  Since the stirrups are molded from styrene, the are much more fragile.

Do Kadee boxcars have Delrin stirrups and/or detail pieces? Is that what you are talking about?

[Spikre]

 
   Kadee HO PS-1s have detail parts of Styrene and Delrin type plastic.
   the end stirrups are on a bar that goes across the cast metal floor.
   doors and roofwalks seem to be Styrene,not sure about the ladders,
   think originally they were delrin, but changed to styrene after a few years.
   underfame seems to be styrene, details brake bars etc seem to be delrin.
   havnt bought any for 7-8 years, so not sure what they are currently.
   the Kits are a good way to check what the latest plastics used are.
   the separate parts are very nice for use on lessor car models.
          Spikre