Re: [Harp-L] re: Breaking-in

[Vern <jevern@xxxxxxx>]

I'm not the one claiming that there is a break-in effect so the burden is NOT on me to prove a negative.   He who makes the affirmation must provide the support.

You have answered a question with a question.  The answer is "no".  However, that doesn't shed any light on the subject.  We should be trying to find the truth here, not win an argument.

Experimentally comparing the fatigue life of reeds with and without break-in would require running many reeds to failure under identical conditions.... a time-consuming and expensive task. 

 If convincing evidence that the fatigue life of copper alloys can be extended by a short period of gentle cycling, it could be very persuasive when applied to reeds.  It is unlikely that the results for reeds and for other applications of copper alloys would be different.

Surely you do not claim that there is something exceptional about harmonica reeds that exempt them from the properties of brass or bronze.

There is an effect called "coaxing" that occurs in iron and mild steel but not in non-ferrous alloys.  A long period of cycling at low stress followed by long periods of increased stress at successively higher levels can increase fatigue life.  However those conditions are not met by harmonica break-in because the reeds are not mild steel, the break-in period is short, and there are no successive long periods of gradually increasing stress.  

I do not claim that lack of evidence is evidence of lack.  However, if anyone can find any reliable information on a similar effect in copper alloys, it would support the contention that harmonica break-in works.  I'm hoping for a response from a metallurgist.

Vern

On May 14, 2010, at 8:23 PM, joe.mahan@xxxxxxxxxxx wrote:

> 
> Vern writes: 
> 
> Q. Can you refer me to authoritative, supporting information in the metallurgical literature? 
> 
> 
> Vern- 
> 
> Q. Can you refer me to any authoritative, supporting information in the metallurgical literature about harmonica reeds? 
> 
> 
> Thanks, 
> Joe 
>