[CAUT] Vs Profelt... again

[Ed Sutton]

Wouldn't it have been faster just to rebush the flange?
ES
  ----- Original Message ----- 
  From: David Skolnik 
  To: caut at ptg.org 
  Sent: Wednesday, December 17, 2008 2:40 PM
  Subject: Re: [CAUT] Vs Profelt... again


  Sorry to be unclear on that point.  I was suggesting using the smaller pin only for sizing the bushing.  When dry, you would use the appropriate sized pin for the birdseye and adjust the bushing accordingly.  It just might need less such adjusting than if there were no sizing pin used at all.  Also, to the extent that there is concern about glue failing, the (small) pin might still function as a clamp, once the bushing has swollen.  It's still not a spray'n-go fix.

  David Skolnik

  At 11:09 AM 12/17/2008, you wrote:

    that's what I was thinking David, but I'm sure that Fred is making sense. What do you do about the flange birdseye being too loose if you use undersize pins with sizing. I guess you glue size the wooden hole or replace the flange. Could be a can of worms?

      ----- Original Message ----- 

      From: David Skolnik 

      To: caut at ptg.org 

      Sent: Wednesday, December 17, 2008 10:15 AM

      Subject: Re: [CAUT] Vs Profelt... again


      Totally unscientific, but I had occasion to try VS on a hammer-pinning center from a Steinway action I was 'de-verting' for a friend who just needed the action free enough to have an idea of what the piano sounded like.  I was using naptha and aggressively working parts (dismounted from the frame...in-place did not seem to work).  Once dry, some seemed to have been worked a bit too aggressively, and were loose.  I applied some VS to the pinned assembly, but it was still too loose when dried, which is what Fred explains below.  I unpinned and reapplied VS (sparingly) and left center unpinned.  When dried, I had to refit pin in (almost) normal manner, and it worked very nicely. Don't know about longevity.  Next time I might try sizing with a pin one or two sizes under.


      David Skolnik

      Hastings on Hudson, NY


      At 08:52 PM 12/16/2008, you wrote:

        On Dec 16, 2008, at 2:52 PM, Chris Solliday wrote:


          Alcohol and water depends on the amount of water, more is more aggressive, but in any case my findings were that VS Profelt is more aggressive in general as a sizing solution.


        There is a pretty obvious reason for this: VS Profelt has a very high ratio of water in its contents. I believe it is in excess of 75% water. It's pretty rare that we use an alcohol and water mix that is 1:3 alcohol to waterl. More common is the opposite, 3:1 alcohol to water. So if you want to compare, it would be a good idea to use a few mixes of alcohol and water to compare to VSP. Maybe 3:1, 2:1, 1:1, 1:2, and 1:3. Or just 3:1, 1:1 and 1:3. I think that would give a pretty fair comparison. (That is, the 3:1 water to alcohol would be a fairly even match, the others would be instructive as alternative strengths).

        About the notion concerning action centers, I don't think a high water ratio there would swell the felt to take up space, like in key bushings, for the simple reason that it is a system that requires a lot more compression and a tighter final fit. If you add a higher proportion of water, it causes more knitting of fibers, hence more "shrinkage," resulting in a looser fit. The "shrinkage" is actually felting, locking the fibers together more tightly. When you apply the stuff, the action centers seize up (applying more compression). When the water evaporates, the more compressed fibers leave space between them and the pin.

        It works for key bushings because there is lots of extra space to be filled in to start with, and you actually want a somewhat loose fit (compared to action centers).


        Regards,

        Fred Sturm

        University of New Mexico

        fssturm at unm.edu




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