Re: [Harp-L] reed tuning questions



On Dec 20, 2009, at 7:30 AM, Doug wrote:

> Hey Sam,
> 
> I really appreciate the input sloppy or not.  Thanks.
> 
> Doug H
>  ----- Original Message ----- 
>  From: sam Blancato 
>  To: Harp-L 
>  Sent: Sunday, December 20, 2009 7:54 AM
>  Subject: [Harp-L] reed tuning questions
> 
> 
>  I resent this post because the other one was sloppy:
> 
>  Doug asks:
> 
> 
>  2. "I've heard that solder can be used to lower the pitch - is that required
>  to
>  get just 4 semitones?"
> 
>  Yes adding solder to weigh down the reed and then tuning back up to the
>  pitch you want is the way to go; you can also remove material from near the
>  base of the reed (the dog) but you are weakening the reed a lot and it won't
>  last.  But soldering is not as easy as it sounds and you have to be careful
>  about staying near the end of the reed and not letting it drip too far
>  toward the middle.  And then there's the issue of cleaning up the sides
>  after adding solder - it's a pain in the first place but 4 semitones is 2
>  full steps - like from A down to F.  That's a lot; and so it means a LOT of
>  solder.  I've tried it (Lee Oskar blues tuning 11.21b) and it worked but I
>  was left with a very dull sounding reed.  It plays but it's much darker than
>  the adjacent reeds.
> 
>  You need to replace the reed with one of the proper pitch, which may have a
>  lot of solder, but done properly and cleaned up and pitched already.
>  Better, I think, to develop your reed replacement skills.

Others may think this unnecessarily involved but I use the following procedure for solder:
I paint the area of the reed where I wish the solder to stick with paste flux, keeping away from the edges.
This avoids the task of cleaning up the sides but may result in less solder than desired.   
I use one of the little battery-powered soldering devices (useless for any bigger soldering job but just about right for reeds)
I use solid solder...not flux core.
The result is a nice rounded blob of solder just where I painted the flux.
YMMV

>  3. It would make sense for me to set up some kind of 'tuning station'. Best
>  not
>  to reinvent the wheel so any info or direction on this would be helpful."

Some hints for setting up your tuning station:
A track on which the very edges of the reedplate rest with a little mouth like the chamber of a comb for a single reed is recommended.
The track needs to be about twice as song as a comb so you can slide any reed over the vacuum mouth.
Fish tank, diaphragm, and piston pumps won't work... too much pressure and not nearly enough volume.
You can use only vacuum by turning the blow plates over so the reeds are on top...where you want to work on them.
The reeds don't care if they are drawn or blown as long as the pressure difference across the slot is about 5"H2O.  
A flat plate with a slot in it won't work because the other reeds prevent the slot from sealing around the reed to be sounded.
An old tank-type vacuum cleaner with its speed, noise, and pressure tamed with a 2kw light dimmer can be used as a pump.
You can improvise a U-tube manometer with clear plastic 1/4" tubing and a yard stick.  It is very helpful to know that you are applying consistent pressure.
5"H2O is a good average playing pressure.
For gapping, a reed that starts sounding at 1/2 "H2O and doesn't choke at 10"H2O is a good starting point.  Then you can reduce the gap "to taste" for bending and overblowing on diatonics.
The low pitched reeds may be reluctant to sound without a chamber around them.  A piece of wooden chromatic comb placed over the reed works.
A small light bulb light under the opening to the reed helps in seeing the reed-to-slot clearance.

Vern
 






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