[ATM] Carbon Fiber and aluminum

[artbianconi@blast.net]

I've been away from hands-on fabrication of composite parts using 
Carbon Fiber. A lot can happen in two years so I did some 
homework. I discovered that the threaded aluminum inserts in my 
carbon fiber truss tubes don't get along with carbon fiber at 
all! Galvanic erosion will attack the aluminum at the interface 
of the two materials and turn it to dust. And, if there is any 
water present, the destruction of the mechanical bond will be 
rapid.

I bounced this discovery off a few aerospace engineers I know and 
they confirmed my worst fears. One wrote back:

"Carbon Fiber does indeed attack aluminum 
VORACIOUSLY if any hint of moisture gets into 
the matrix.  All the metal parts on the F-16 fighter that
contact CF are Stainless Steel,  Passivated too if I am not 
mistaken to more closely match the electronegativity value of the 
two materials."

If you propose to develop an OTA using carbon fiber, be certain 
that your choices of metals and fasteners are CF tolerant,  or 
insulate them first from direct contact with an intermediary 
layer of fiberglass

Art Bianconi

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