[Harp-L] Re: Vibratory Stress Relief

[Michael Easton <diachrome@xxxxxxxxxxx>]

Hi Rick,
Since I get the digest I don’t know if any replies came in yet after your posting. 

Have you tried checking the other reeds before placing the plates in the ultrasonic? 

I’m guessing the change in pitch might not be the reed relaxing but the scraped reed material flaking off the reed that is contributing a bit to the 
raise in pitch.  Yes, it could be helping with speeding up the relaxation but I’m just saying there might be a bit more to it to contribute to the change in pitch.

I’ve used files, very sharp dental burs and Shofu Brownies in rotary tools and found the Brownies required the least amount of adjusting since the reed was being
polished, followed by the dental burs then files and scrapers requiring the most adjustments after replacing a reed. 

I think in general if you can place a set of plates in an ultrasonic before checking the tuning you can get a more accurate reading due to the lack of saliva and oxide buildup
hanging around on the reeds and to some degree the windsavers on models having them. 

Mike
www.harmonicarepair.com




On Nov 3, 2014, at 10:46 AM, harp-l-request@xxxxxxxxxx wrote:

> 
> Message: 11
> Date: Mon, 3 Nov 2014 15:37:58 +0000
> From: Rick Epping <rickepping@xxxxxxxxx>
> Subject: [Harp-L] Vibratory Stress Relief (VSR) for reeds
> To: "harp-l@xxxxxxxxxx" <harp-l@xxxxxxxxxx>
> Message-ID:
> 	<CAJFTUGwuePAe6FTPu0YFAkALaSq2dhusPDf1n8OxzFAmEJNB2Q@xxxxxxxxxxxxxx>
> Content-Type: text/plain; charset=UTF-8
> 
> Hi folks,
> 
> This message is about one possible benefit of using an ultrasonic cleaner
> on newly replaced reeds.
> 
> The work that reeds are subjected to through such procedures
> as profiling, riveting, centering, chamfering, curvature adjustment and
> gapping, adds stress to the reeds.  As the tuning of a reed can be affected
> as a reed de-stresses, the Hohner factory gives newly assembled reedplates
> a rest period to de-stress before tuning.  Alternatively, Asian harmonica
> factories heat treat reedplates to de-stress them.
> 
> In my experience, new replacement reeds that I have riveted onto a
> reedplate tend to go up in pitch over the course of a week or so, and
> require an additional tuning once they become stable.  Lately, however,
> I've been using an ultrasonic cleaner in an attempt to VSR treat plates
> with newly replaced reeds, and find that after using the cleaner's maximum
> time setting of 8 minutes, new reeds increase in pitch by as much as 8 or 9
> cents.
> 
> I've only been paying attention to this effect for the last half dozen or
> so reeds I've replaced and have not as yet experimented with employing
> longer periods of VSR, but it looks like it might be a useful treatment for
> quickly stabilizing a reed's tuning, if not also for delaying the onset of
> reed failure by elimination of residual stress before a new reed is
> subjected to playing.
> 
> More on the subject of VSR here:
> http://en.wikipedia.org/wiki/Vibratory_stress_relief
> 
> Best regards,