John McCoy wrote:


It's also worth noting that not all plastics are equal,
and an application where a fiber reinforced plastic like
Delrin is suitable wouldn't work with something like LDPE.
Especially in the 80s you saw a lot of metal subsituted
with weak, unsuitable plastics, where now better material
choices are being made.


I agree with this John. It was a live and learn sort of experience, and
we've come a long way in understanding synthetics and how to apply them.
Lots of 16 and 18 guage steel was successfully replaced by plastics (sorry -
I really don't understand plastics like you do, so I use the inaccurate term
"plastics") that provide resistance to rust and ridigity required in today's
automobiles. Like I say - many of these parts really did not reduce weight
very much - if at all, but brought a different economic value to the
picture. Now, bumpers on the other hand...

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-Mike-