Unless you remove the pin from the flange, no matter what type of heat you use (soldering iron or zapper) the pin is conducting heat to the birds-eye. Now if you remove the pin and disassemble the flange, reinsert a pin and heat it, then it's a whole different ball game. Ironing down the fibers is going to be a good thing if not overdone and scorching the cloth. There has to be some temperature limiting system. Sizing the felt with a shrink solution, with a pin inserted, works well to compact the felt in the bushing. It seems to me, though, that doing that makes it likely that a big increase in humidity is going to re-swell the bushing again. Back to square one.
I'd like to hear from some old-timers about this process of shrinking/sizing the bushings, and the longevity of it. It seems that on pianos made overseas (China especially) that bushings seem more prone to seizing because of the climate change.
Paul McCloud
San Diego
-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of Poppy Miles
Sent: Thursday, March 04, 2010 10:05 AM
To: David Ilvedson; pianotech at ptg.org
Subject: Re: [pianotech] Center Pin Zapper
Although I'm still entertaining the idea of making a zapper ( I saw one that seemed to work without burning the birdseye or the bushing cloth). This zapper is pretty elaborate, and manages to deliver a very small charge through the pin, and has a beeper that goes off when you locate the sides of the pin with sharpened tongs made of spring steel ( the charge is deadened with a block of wood where you grab it.)The main thing that has discouraged me from making a copy of the one I had used, is I don't like the idea of heating up the birdseye. I've heard they can be worse than a waste of time. I would have to make, and study the effects of this tool on a scrap part beforefeeling confident it would be safe and reliable. A few of you said they are not. Without a sort of experiment where the humidity is controlledor measured alongside a reamed part, I can't be sure. Reaming workswell, but all pinning changes with humidity. Also, after reaming
thebushing cloth is fuzzed up, so the action center needs to be worked in order to smooth it. You also have to be very careful to ream evenly, and there is a chance of pushing out a bushing. Sometimes, after repinning the part becomes looser, because the part wasn't worked enough.I've seen alcohol/ water treated bushings regain a little of their tightness, but I'm not sure if that was due to a change inthe humidity or not. It's also easier to get a small change with reaming, than with a solution. You also have to wait for it to dry. I've saw a demonstration at convention where the lecturer used the old trick of heating up the centerpin with a lighterto loosen it. I tried this and wished I hadn't, ( the bushing looked a little charred). I'm sure there are people who this technique works well for, but I will pass. I do actually reason forgiving youall this well known info: all methods seem to have drawbacks. So why not try a new one? My key
bushing iron works well, so maybe using heat instead of electricity, reaming, or solutions could work. Maybe there's not enough pressure on the bushing with a zapper, and the problem of heating the birdseye could be eliminated ( by separating the parts.) If anyone feels like designing a heated centerpin caul type tool ( modified soldering iron attachment), avariation on the lighter method where the amt of heat would be controlled more carefully,I think it might work. That said, I will continue using my reamers, after all, I am patient as is anyone who has read this incredibly long post.
----- Original Message ----
From: David Ilvedson <ilvey at sbcglobal.net>
To: pianotech at ptg.org
Sent: Wed, March 3, 2010 5:49:44 PM
Subject: Re: [pianotech] Center Pin Zapper
Yes...zapper is a waste of time
David Ilvedson, RPT
Pacifica, CA 94044
----- Original message ----------------------------------------
From: "Gregor _" <karlkaputt at hotmail.com>
To: pianotech at ptg.org
Received: 3/3/2010 1:26:13 AM
Subject: Re: [pianotech] Center Pin Zapper
>I never heard of that idea of a zapper and it sounds really weired to me. How long
>does it take, I mean how long do you zapp one center pin? Would it not be easier,
>quicker and more long lasting to replace that pin?
>Gregor
>------------------------------------------
>piano technician - tuner - dealer
>Mnster, Germany
>www.weldert.de
>> Date: Tue, 2 Mar 2010 15:09:57 -0700
>> From: mark.purney at mesapiano.com
>> To: pianotech at ptg.org
>> Subject: Re: [pianotech] Center Pin Zapper
>>
>> I've heard other claims that the results can sometimes be permanent, or
>> at least long-term. Maybe the ironing effect of the heat reconfigures
>> the bushing fibers in some cases, but not others? I'll experiment and
>> see what kind of results I get - it's not a complicated or expensive
>> device to build. Thanks for the information!
>>
>>
>> On 3/2/2010 1:57 PM, Michael Magness wrote:
>> > I have one I rarely use, it's results are temporary at best. The
>> > results of the device is/are heat, resulting in drying the flange
>> > bushing cloth thereby cauing it to stop sticking. The problem of
>> > course is that the humidity returns and with it the problem.
>>
>
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