Doping pins.

[Baldwin Yamaha Piano Centre]

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>Hi Bill,

            A good post, lets have more like this.
Roger


>Although I rarely get involved with something like this, there is a time 
>and place for everything.  There is a friend of many years who has a Lyon 
>& Healy grand that has been sitting around in unplayable condition for 
>about 10 years.  It really needs rebuilding but there is no way he could 
>afford that.  The soundboard and bridges are in flawless shape.
>
>Upon inspection, the pinblock looked good too with no visible delamination 
>but many of the tuning pins were uncontrollably loose.  I decided that 
>this was a good candidate for CA glue pinblock doping.  Last weekend we 
>did the doping job and today I will go finish the project.
>
>I look at it from a theoretical point of view:  couldn't I surround more 
>of the pin more effectively by first turning the piano over and doping 
>from the backside, then from the top?  Not only did this work very well 
>but upon doping from the backside of the pinblock, there was some seepage 
>through to the edge of the pinblock between the bottom two 
>laminations.  This told me that even though the block was not *visibly* 
>delaminating, it was in fact very weak, enough so that the glue seeped 
>through.
>
>The whole idea of using CA glue is that this substance will fuse together 
>any structurally weak parts of the block.  The other kinds of dope which 
>are merely intended to swell the wood cannot provide any structural 
>strength the way CA glue does. Upon doing the first rough tuning, each pin 
>was stuck hard and took some real muscle to move it.  But afterwards, the 
>feel was amazingly normal and smooth (not jumpy as might be expected) with 
>very high torque, about what you'd expect from a new pinblock.
>
>The hammers were worn enough to need replacing but the customer not having 
>enough to pay for that, I just decided to give them a good filing.  The 
>let off was about 1/2" but after a good knuckle bolstering job, it brought 
>the let-off right up to where it should be with a few hammers even 
>blocking slightly.  It lifted all the shanks off the rest rail too. Today, 
>I'll go over the regulation but I don't expect to have to do a lot.  I'll 
>give it two more tuning passes (a total of 4).  We had to overhaul the 
>pedal box but aside from that, just a few basics like this will bring the 
>old grand of fairly good design back to life for a few hundred dollars.
>
>Another younger tech who is still learning the trade is participating and 
>the customer himself did the doping.  We had fans blowing full force with 
>all the windows open to evacuate the fumes which were pretty intense at 
>times.  Like the recent thread on Spinet Grommets, involving the customer 
>of modest means and maybe another tech who is learning the trade can be a 
>way of lowering the costs to the customer and having that person be really 
>grateful.
>
>Everyone enjoyed the session, we broke for lunch and another couple of 
>iced tea breaks which we'll do again today and have a very well spent 
>day.  Tonight, undoubtedly, there will be music flowing from that house 
>all evening long.
>
>Bill Bremmer RPT
>Madison, Wisconsin
><http://www.billbremmer.com/>Click here: -=w w w . b i l l b r e m m e r . 
>c o m =-

Roger

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