Re: [Harp-L] Carbon Fiber Reeds, 3D printing, plastic metal adhesion technology...?

[Vern <jevern@xxxxxxx>]

On Feb 20, 2013, at 12:06 PM, John Ingham wrote:

> What can you tell me about the possibility of carbon fiber reeds,
> products, experimentation. Is that just a crazy notion?
> 

Carbon fiber has a very high strength-to-weight ratio making it ideal for many vehicle applications, particularly aircraft.  It has another desirable property in that the epoxy matrix absorbs vibrational energy.  However, these properties may make it less desirable for reeds which act as springs.  To my knowledge, carbon-fiber composite is not used for springs.

In reeds, you want a material that stores, not absorbs vibrational energy.  The pitch of a reed is determined by the square root of (k/m) where k is the "springiness" of the reed near the rivet where it bends and m is the weight near the tip that deflects.  You would probably have to attach a weight near the tip of a carbon reed to achieve the customary pitch-length relationship.

IF it were not for rust, spring steel would be the ideal material.  If you want to experiment, maybe a thin, protective coating could be developed.  Manufacturing spring steel and tuning would be problems to be solved.  The material that makes the best spring makes the best reed!

Vern