Piano World Home Page Forums Our Most Popular Forums Piano Tuner-Technicians Forum Pins all glued...can they be "re-glued" later?

Just so I'm clear and have a solid answer for my customers. If I tilt a piano and CA glue all the pins can I do the same thing to the same piano a few years (whatever) down the road if I think it needs it? Sometimes you come to a piano that the pins have been all glued and yet it is time to either do it again or do something more expensive or send the piano to the land fill.

So, again, the question is "If I tilt a piano and CA glue all the pins can I do the same thing to the same piano in a few years if the pins are no longer holding again"?

Duane,

My experience is "sometimes yes, sometimes no". It depends on the circumstances. I always present it to the client as a risk/reward ratio and that there is a slight possibility that it might not work as well as hoped.

If you, or someone has globbed it all over the plate and tuning pins (a sloppy job) then the likelihood of being able to do anything further later is reduced. Be neat and only do enough to get the needed torque. Don't try to get the max out if it. Plus, you can still put in a larger tuning pin later if needed for spot improvement.

Peter Grey Piano Doctor

Basically, no. If there is a complete "seal" of the wood, then it is not going to get in there. If there is some open spaces, then maybe. That is why I don't think people should be doing this unless it is the LAST stop before the piano goes to the trash.

Changing the pin is the right thing to do. It's $100 for the material, and less than a days work. We're not talking about a lot of money here. Besides, a fresh tuning from the beginning really improves the sound quality anyway.

If done with care and not going for a 'quick fix all at once' - then yes. That is why I don't tip the piano, goop it on and try to seal up everything. Essentially, the approach I use is to create a starved glue joint between the pin and the pinblock. Thin glue gets pulled in by capillary action and then pulls away from the pin into the wood, leaving room for further application.

10-15 minutes of careful work - possibly repeated over a few yearly tuning visits if it is needed. I've got pianos out in the field where this has held up over 30 years now, so it's not really considered a temporary or 'wrong' way of doing things anymore. Much better than splitting a block more by putting in oversize pins - in my experience.

Ron Koval

I agree with Ron.

Peter Grey Piano Doctor

OK, that never happens. Tuning pins are self-reaming, which is why you never need to drill out tuning pin holes to begin with. The only way that splitting a block could occur is if someone is trying to force in a pin that would otherwise be untunable or useable anyway. Besides, there is no such thing as an "oversize" pin, unless you are talking about a size that is not commonly available or doesn't fit the plate.

There is a "right" way of dealing with this kind of situation. This is why we have three lengths of tuning pins and increasing widths. This is, in addition to pin height, is how to create consistent response at the tuning pin, and it has been this way since at least the time of the harpsichord.

With crazy glue, there is no control.

Well of course it happens - in a weakened block where the pin is getting loose because of the beginning of a split, putting in a pin larger just expands that split. I've seen where one problem pin expands to a row of problem pins using this method.

There are 'old' ways of dealing with this kind of situation, some work better than others... There are 'newer' ways of dealing with this kind of situation, some work better than others...

Perhaps the only 'right' way to deal with a deteriorating tuning system would be to install a new block, or perhaps drilling out, plugging, and redrilling to get the assurance of beginning anew.

Plenty of control with cyanoacrylate glue if the protocol is designed for control.

Ron Koval

OK, I can agree with that. If a pinblock is already split, then CA could be a better option than new pins.

But, as it refers to the OP's question, the only control you have is to do a little bit, and if it doesn't work, then do a little more. There is a point at which the glue doesn't work anymore. You can control the amount of glue applied, but there is very little control in the amount of torque control felt at the pin. It is more or less a go or no-go kind of thing.

I am not a fan of using any adhesives here, including CA. Yes, CA may and should be a savior, but
Pure practical physics is that if we take a larger diameter of a pin("oversize") or a cardboard shim, then we solve the problem of mechanically changing the friction between the pin - hole. AS wedging.
Whereas the increase in friction with using CA is a partial glueing there. How the pin used CA will behave in the future, we cannot know and guarantee the client its functionality, I'm think.

My own experience with repinning, whether done by me or someone else, is that the repair does indeed work. However, the larger diameter pins put more stress on a block which has already begun deteriorating. Net result is loose pins again in maybe 10-15 years. Careful application of CA seems to last at least as long. Given the significant difference in cost to the customer, CA (or even driving the pins) is a much better option in my opinion.

I think Chuck Behm's beautifully written and illustrated "Promo" about the CA treatment is very useful for printing out and handing to customers, to explain the process.

http://www.pianopromoproductions.com/piano-promos.php

If you mean a cracked tuning block, then yes, a larger and/or longer pin could put more stress on a deteriorated block that needs to be replaced.

If we are talking about a normal loose tuning pin that has occurred naturally through use, then no, a larger and/or longer tuning pin doesn’t put any additional stress on a block. The new pin will last as long as the original pin. It’s not measured in years, but in the amount that it is used. Tuning pins are self-fitting, so it is like brand new. This is one of the reason we tap in.

Careful CA does not last as long as a fresh pin in pianos that are tuned often. But, it may be OK for a piano only tuned 3-4 times in that 10-15 year period.

In my experience, the pianos where CA glue has been applied correctly, this is the not the case. Do you have evidence of this?

Yes.

A new pin in a new pinblock and a longer/thicker pin in an older block function the same in terms of usage and longevity. Both those scenarios outperform a CA saturated pinblock and pins in high use and often tuned pianos.

Greetings,
I have not found this to be true in my experience. Pinblocks wear at the top of the hole, not the bottom. A longer pin or tapping a loose pin in reverses the normal location of friction. It is also difficult to gain more than 3 mm of unused pin block by tapping them down, which is a marginal improvement on a bass string's pin. I have a number of CA treated pins in pianos that are tuned quite often, and the treated pins are easily as durable as oversized ones. Tapped pins have not shown any more longevity than the CA treatment, and I have had several cases of tapped in pins becoming too loose to use after several years. In those cases, a treatment of CA usually restored the torque needed for tuning stability.
I would also add that frequent tunings are not detrimental to the torque. Our stage pianos at Vanderbilt, and more than a few recording studios are tuned over 150-200 times per year and I have seen no increased wear on the blocks in comparison to the home pianos that are tuned every leap year or less.

It is my belief that it not tuning per se that wear a a pinblock, but rather the simple fact the structure is under tremendous stress 24/7/365/30 and this alone (coupled with extrenes of humidty/dryness) will cause the upper portion of the tuning pin hole to enlarge, and the pin to get loose.

Tunings on concert instruments involve extremely small pin movements. Rarely a substantial pitch change. The pin movement is negligible and therefore not detrimental from the standpoint of turning. A home piano could be subjected to numerous significant pin turnings as efforts are made to tune and retune to pitch. Still, I believe the majority of wear and tear is just from being pulled on by 150-230 lbs of tension all the time.

It's part off the design lifespan.

Peter Grey Piano Doctor

My experiences is completely different.

I can imagine that some people's tuning technique enlarges the top of the hole. That is a tuning technique problem. I have seen the consequences of other people doing that especially in the top of the piano. With normal tuning technique, this is no destructive enlargement of the hole.

There is no such thing as a proper pin height. The concept doesn't even exist. Pins are tapped in as they loosen, so the piano maintains consistent pin tightness throughout the lifetime of the block. When the pin gets too close to the plate, you simply exchange the pin. This is usually 2 increments larger. If you are on a 3/0 small, then you go to a 3/0 long. Experience will tell you if you should go more or less than that. With a properly maintained piano, you have consistent feel at the pins for the lifetime of the block. This is how we control the torque over time and achieve extremely consistent note-to-note consistency.

There is no such things as a reversal of normal friction location. There is literally no difference in pin response between a properly fit short and long pin of the same thickness. That's why this has been done this way for centuries. Traditionally, builders have been taught to conically ream the blocks after they are drilled. The most friction should always be at the bottom of the pin, never at the top. Reversing that concept is not even possible.

I have a piano with over 10k documented tunings on it. It still has the original block. Also documented is every pin size and height. What I can say, without a doubt, is that in the sections that require more tuning attention, the pins have been swapped out much more than the other areas. There is absolutely no question that, the more the piano is tuned, the more the pinblock wears out. That part is physics.

Home pianos, you will tune them more-or-less consistently through with about the same kinds of movements. With high use pianos, you'll focus more in the capo. The middle of the piano usually doesn't require that much movement comparatively on a frequently tuned instrument.

I think there are several different things being conflated here, that need deconstructing.
The first question is why does this pin need attention.
The second is where does our experience belong. Am I tuning lots of domestic pianos once or twice a year? Am I in a wealthy area where most of these pianos are new or at least under 30 years old? Or am I trying to keep a hundred year old piano going for a family with not much disposable income?
Or am I tuning concert and studio pianos, every day or twice a day, or twice a week?
Clearly these different scenarios need different solutions.
Obviously, if money is no objection a new pinblock is ideal.
My personal experience with concert and studio work is that the piano never gets old enough to need anything to the pins. It's been sold long before trouble, replaced by a new one.
So my experience with pin problems has almost always been in domestic situations. So, one pin is loose. I need to ask why. If the wood has softened then replacing the pin with a bigger one is a very short term fix (that's my personal experience). Very quickly, and I'm talking about one tuning a year remember, that new pin is also loose. In this situation CA glue is very good. I was a very reluctant glue user for a lot of years but I was converted after trying it. For one or two pins in an older piano it's a no charge fix. An extremely small drop in the right place just solves the problem. Effectively for ever.
Or maybe there is a line of loose pins? In these cases the block is almost certainly cracked. Again, reluctantly, a good few years ago, I tried the glue as my client had not got the financial resource to have a major repair. It worked very well, though much more glue needed of course.
I have found over my 40 years with pianos that sometimes it's hard to move to a new technology or technique. But we need to be able to accept things.
A pitch raise used to take me a couple of hours and a second visit a week later. Now, with the magic of tunelab, I can do it in an hour and a quarter and no second visit needed. OK it's the client who saves money but with the luxury of being so busy I don't need to charge more than I have to. And the client thinks a miracle has happened and tells a friend or two....
I have glued a whole piano sometimes. Each time it was an old piano which had value emotionally for the family but was not worth the cost of a new block. It's a very cheap cure. So, if it only gives them 10 years it at least gives them time to prepare for the cost of a new piano.

Like so many of these discussions, we seem to try to have one answer for an infinite variety of situations. Surely the more tools we have available enables us to approach each situation with a set of alternatives to offer the client.

That's just my few pennies added to the discussion.

Nick

My experience with domestic pianos is that the middle moves far more than the ends. Here in UK humidity changes mean the soundboard goes up and down alot. So the middle can easily be 10 cents sharp or flat and the two ends needing nothing at all.
Nick