Rotary Engine wrote:
    > The local aluminum radiator supplier recommends the plastic tanks
   ( on his
    > website) before I contact him, what is the recommendation on the
   plastic
    > tanks - I heard they were prone to failure much more quickly than
   the full
    > aluminum ones. I'm sure the racing people use full aluminum,
   perhaps for
    > that reason.
    > George (down under)

   Plastic tanks have been used since the 1970s.  They are reliable.  I
   would never use one in an airplane, though, because the few ounces of
   extra weight is a small price to pay for the significantly greater
   strength of aluminum tanks.

   Keith Wood

   Most hard plastics in cars last about ten years here in Socal and then
   become
   brittle and crack easily. I am no expert on plastics by anybodies
   wildest
   imagination but I think it is a process called out gassing. If you can
   smell it--- it is out gassing. Certain compounds are leaving the plastic
   changing its mechanical properties.

   Non metallic objects going into space are tested by cooking them in a
   vacuum chamber. One example I know for sure is the Space Shuttle
   tires. Black "rubber" hoses and is another material that
   self destructs over time. According to Cummins engine manufacturer
   silicone hose does not. That is also a reason why new cars have a
   smell.

   I would never ever use plastic rad tanks. One crack could kill you.
   --
   Paul Lamar ...No rotor no motor.

   That isn't what causes plastics, in general to become brittle with
   age.  It
   is mostly attack from ultraviolet light.  Plastic isn't like rubber
   in that
   they add oils and other "plasticizers" to reduce hardness.  I think you
   should stick to the aluminum tanks, I don't think you even save any
   weight
   with the plastic tanks.  I've also seen people take the plastic tank
   radiators that have the right core and make their own aluminum tanks for
   them.

   Steve Brazil

   Ultraviolet light may affect some plastic parts but I don't see how
   it affects plastic parts buried inside a car door upholstery for one
   example.
   First gen RX7 nylon door pulls fail after being completely covered up.
   Also the plastic rad tanks are under the hood 99.9% of the time where
   they cannot see the ultraviolet light. Cracking is a common problem.

   Paul Lamar ...No rotor no motor.


Ozone (too)?


Matt-


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