Hi Paul,

  I was on the thinking seat, and remembered something I read about the
  deterioration or break down of carbon fiber race car tubs. I do
not know  if  this was a result of the material failing due to age
or from the abusive  environment of a race car. The stiff suspension
and repetitive shock  loading  from bumps on the track may be the
cause. Or is it a result of exposure to  UV  light and or dark paints?

  How would this relate to carbon fiber aircraft construction? I
know that  composite construction is sensitive to color from heat
build up from dark  paints. Turbulence and hard landings will put a
stress into the structure.  All  materials will fail eventually due
to applied stresses. That was the cause  of  the Air Hawaii failure.
Part of the solution is the design of attachment  points to
dissipate applied stresses to reduce them safely.

  I also saw recently on How Stuff is Made about the construction of
  Kenworth
  trucks and also the new Lotus car. The both bond parts of the cab
(truck)  and  chassis (Lotus) together.  The Lotus uses extruded
aluminum to make the  chassis. The epoxy is applied and the parts
are held together, until they  can  be cured for a couple of hours
in an oven. Does the curing enable the  proper  adhesion or is there
a chemical etch like you recommend also used? This  could  make for
very clean aluminum skins. You would not have the stress points
that  you have with rivets and stresses would be dissipated over a
large area.

  Dale Davies

  I have no knowledge of that. There are some fiberglass boats still
  around after 60 years. It does not appear to fatigue and crack
like metal.  When we were racing fiberglass tubs back in the 1960's
they never seemed  to develop any problems.

  Paul Lamar

I was told that carbon fiber causes severe corosion to aluminum;
I would certainly check if this is true.

JP

There is a few different things here.

1: Fiberglass/foam core composite construction.
2: Degradation of carbon fiber with age.
3: Bonded aluminum construction without welding.

We know not to paint foam core components a dark color because heat from
sunlight will cause a failure at the foam. Plain GRP is very durable.

I was asking about possible failure of carbon fiber with age. Possibly brought
on by severe environment of open wheel racing. The failure I read about could
have been caused by a repair made years prior.

The bonded aluminum construction and getting proper adhesion. Do they use like
the West etch or some equivalent or does the heat of the oven cure it to adhere?

Thanks

Dale Davies