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Scott Dahlgren makes a very good point in the cautionary statement about

mixing materials. While the hope of the designer is always to achieve

the best of both without the drawbacks of either,  this is often an

evasive task, especially with carbon fibre! Depending on the modelus of

the fibres and the VERY INDIVIDUAL properties aquired with the

INDIVIDUAL reisins,  you could be setting the stage for a failure event.

One of the most infamous large scale examples of catastrophic failure of

combined materials came about during the 1979 Fastnet Yacht race. EVERY

yacht (we're talking about professionally designed/extravagently custom

built, no expense spared) that had combined carbon and aluminum in the

rudder shafts failed when a severe storm ran over the fleet and

subjected these shafts to high loads.  It is interesting to note that

the rudder shafts were "designed" and expected to withstand these loads,

but as no one had ever tested the new and improved combination of alum

and carbon to failure, the high end of the envelope was unknown.  As

carbon was the new kid on the block at that time, it was thought that

the high strength and light weight would be "backed up" by using a known

material (alum) in combination.  15 men lost their lives when their

vessels couldn't take the strain. Yacht racing also showed that exotic

materials can be used with excellent results (carbon w/ kevlar, carbon

w/boron, etc).  The key for the high stress tests seems to be to find

materials that will work in tandem with a compatible reisin.  Carbon

qualities of high tensile strength can work against you when combined

with a "stretchy" reisin and then oriented so the load is tortional or

on the bias.  Combine both carbon and glass (E glass? S glass? or exotic

matrix?) with different reisins and you will aquire different

qualities.  Just remember to test a sample to failure under reasonably

controlled conditions (in all modes including tension, compression,

torque, as well as bending tests) prior to comitting yourself to the

marrige.  Regards to all and praise to Marv for this wonderful

opportunity...  Jeffrey B. Chipetine