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Joined: Mar 2009
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I prefer to do the job by replacing each and every centre pin as needed, looked a bit inaccurate, takes much longer filing the swollen felts down.
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I believe the Zapper is just one more tool to have in your "bag of tricks". I think it can be of real use in repinning actions. It may allow fine tuning of the flange friction. For instance when you repin the part but its just slightly too tight you can loosen it up a smidgen with a 1 or 2 second zap. Repinning is not very effective for verdigris actions in my experience. The last one I did, in order for the parts to be free they had to be pinned so loose that there was noticeable degradation of tone. The verdigris seems to grab at the pin even though the pinning is not tight. The heat seems to release the grabbiness of the verdigris and allows the part to work without it being to loose. If the money is not available to replace the parts this may be the next best option. Here are some pictures of Del's Zapper:
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Joined: Sep 2004
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The heat is somehow affecting the felt--much like ironing it, I suppose. The zapper would have to supply low voltage and a fair amount of current. It would not be dangerous to use both because the voltage is low, and because the transformer(s)in it isolate its output voltage from the line. I have used a heated center pin to size new bushings with good result, and the zapper looks like a more sophisticated way of doing the same thing.
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Ryan, does yours have a buzzer or other sort of indicator? I have one in mine so that it buzzes when contact is made and current flows. Helps prevent burning the felt.
x-rpt retired ptg member
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No buzzer on this one. However I can feel a small vibration when it is active. When my hair stands on end that's how I know its working!
Actually, the buzzer or an LED would be useful. Good tip!
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Rather than a simple transformer a “Constant Current Source” ( http://www.ietlabs.com/IET/VI-700.html ) would be better. The device puts out whatever voltage is required (up to a point) so that the amount of current (which is what produces the heat, not the voltage) is constant regardless of the resistance between the probes and the pin. Then the amount of heat that is applied can be regulated by how long the circuit has been made rather than how much smoke is produced. I haven’t looked, but I am sure these come up on E-Bay, or a circuit with an adjustable timer could be constructed without too much trouble. A Ham radio buff could probably do it easily. I know I could. The heat may not affect the felt as much as it affects whatever gunk is making things sluggish. A larger amount of heat for a short time (zapping) is probably better than low heat for a longer time. But then I’ve never tried it, just my thoughts on it.
Jeff Deutschle Part-Time Tuner Who taught the first chicken how to peck?
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SWEET!!!!!! I know now that I'm not the only one to have one of these.... I have one that I made my self based on one that a retired tech in my town has. Mine is not as pretty as the one in the pics. It looks like some thing from Frankstein's Lab- a huge switch with a large transformer and a small bulb that goes out to indicate contact of the probes.
I found that from time to time that Verdigres builds up on pins and Zappering helps a lot. If its normal swollen felt then I'll repin or chemically treat. If I see green crud on the pins then I zap.
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Joined: Sep 2003
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What's interesting, Jerry is that you hold onto the tweezers while you do the zapping so the current is running through YOU as well as the centerpin. But I think it's like putting your finger across a 9-volt battery - you don't really feel it. Yet as Horwitzian observed, put tin foil across the battery and you'll get some heat! When you find that multimeter you might try measuring your body's electrical resistance and then compare that with the electrical resistance of a center pin. ddf
Delwin D Fandrich Piano Research, Design & Manufacturing Consultant ddfandrich@gmail.com (To contact me privately please use this e-mail address.)
Stupidity is a rare condition, ignorance is a common choice. --Anon
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Before this thing becomes so technologically advanced it can't be put together without a built-in microcomputer chip and a couple of servos, let me remind folks that these things are supposed to be simple. Mine was built using a 6.3 vac filament transformer. Back in the day they were readily available just about anywhere really cheap. Now that vacuum tubes are no longer in common use it might be necessary to ask somebody at Radio Shack. Personally, I'd not go any higher than this in voltage. Remember these things are a short-circuit sort of device and using a lower voltage tends to hold the current down some. I put a simple push switch in so I could better time the application of current. An argument could be made that this is not strictly necessary but it also keeps the thing from shorting out when you lay the probe across the end of your screwdriver. The probe is made from an old set of tweezers broken apart and separated by a wood block of some sort. It ain't fancy. And it certainly ain't complicated! You don't really need any kind of indicator that current is flowing. You can kind of feel and hear the thing in operation. They are not, nor were they ever intended to be, a cure-all device. Nor are they the magical fix for the Dreaded Verdigris. They do one thing, and that only: they heat the center pin and dry out flange felt. In the process they tend to shrink and "iron" the felt some. Used correctly the effect is frequently long term. Like most tools it takes some getting used to. Yes, it is possible to burn the wood in the flange fork. But, using a 6.3 vas transformer, it does take some doing. I do remember encountering a few actions in which using the zapper did loosen the pin in the fork but these pins were already on the loose side and--though this is a guess on my part--I suspected the wood was a bit on the soft side. Not every action builder used hard maple, you know. I stopped using it, not because it didn't work, but because I rarely, these days, work on actions with original action centers. If I come across an action with a bunch of sluggish action centers that needed a quick and cheap fix I'll probably start hollering at Ryan to get the thing back. ddf
Delwin D Fandrich Piano Research, Design & Manufacturing Consultant ddfandrich@gmail.com (To contact me privately please use this e-mail address.)
Stupidity is a rare condition, ignorance is a common choice. --Anon
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OK, back to reality. I just realized there is an off the shelf tool that produces heat with the shorted secondary of a transformer: a pistol grip soldering gun. It probably has about the right wattage for the job. I’ll play around with one and let you all know in a day or three.
Jeff Deutschle Part-Time Tuner Who taught the first chicken how to peck?
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All:
I think a pistol type solder gun can be easily adapted into a center pin zapper. The cheap one that I have is a 65 watt model. It puts out around 130 Amps at ½ volt. I made probes out of some copper wire, but brazing rod would be better, and zapped some old flanges. At full power it took seven mississippis to produce smoke. When plugged into my light dimmer outlet, which I use for regulating the heat on the shank bender and on the hammer iron, and turned down for ¼ volt output it took 40 mississippis to produce smoke.
Of course a solder gun could be dismantled and all kinds of probes and bell and whistles could be added. For instance, the temperature of the pin will be proportional to the change of current while it is being heated. Resistance increases along with temperature. An ammeter installed on the 120v side could be used to regulate the temperature.
I wish I had had a zapper on a certain spinet that had sluggish whippen flanges. I can imagine that using a solder gun with brazing rod probes of the right length and wedge shape could have worked well with the action in place.
Jeff Deutschle Part-Time Tuner Who taught the first chicken how to peck?
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Piano
by Gino2 - 04/17/24 02:34 PM
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Piano
by Gino2 - 04/17/24 02:23 PM
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