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

In composite seminar at Osh last week, they said NEVER attach carbon fiber to aluminum directly.  It is metallic and will get electrolysis and death.  Cant remember just now what you put between.
 van