Piano World Home Page Forums Our Most Popular Forums Piano Tuner-Technicians Forum Hammer Lacquer

Hi Gang,

Often the use of lacquer on the hammers is met with negative reactions.

Isn't it nothing more than one of the many techniques which may be used for hammer voicing? Why is it considered so "evil?"

If the results are good, why not?

There are two components to the function of a piano hammer that go far to describe its performance in a piano. The two we are most concerned with are the hammers linear spring gradient (linear stiffness) and its effective nonlinear exponent.

Without going into the whole 3-hour lecture I'll just say that the linear spring gradient basically defines the hammer in terms of fundamental tone quality—bright, mellow, etc.—while the effective nonlinear exponent determines its ability to produce a wide dynamic range in the tone quality of the piano.

The two characteristics of the hammer that give it these qualities are the physical nature of wool fibers and felt and its shape. Once pressed the hammer will exhibit some measure of stiffness and some measure of resilience. Adding chemical hardeners to a hammer coats and saturates the wool fibers. This increases the linear stiffness and decreases the nonlinear exponent. In other words, the hammer becomes harder and less resilient.

The effect is non-reversible; once it’s in there it’s in there and the wool will never be the same again. True, an over-hardened hammer can be made less hard but it can never get its resilience back.

I will repeat my hammermaking mantra: From the time the hammers come from the press everything that is done to them is destructive! The best hammermakers are aware of this—even if they haven’t articulated it in quite the same way—and try to press hammers with the shape and mechanical characteristics necessary for good performance without their needing a lot of manipulation by the voicers.

ddf

That's kind of my thinking on it.

I know plenty of technicians who view lacquering hammers as a... brutish way to go about providing the tone you want - and I'm sure there are plenty of technicians who go too far, or use too strong of a solution at the outset, thereby turning hammers into rocks. I suppose in many technician's eyes the ideal is to have a hammer that requires no chemical agents to provide the tone you want. Certainly we'd all love it if the hammers required very little work. But, if you're a fan of the classic NY Steinway sound, that sound owes a lot to lacquering.

I'm especially sold on the value of lacquering after seeing first hand the incredibly transformative results that just lacquering a set of overly soft hammers can do in taking a dull and anemic sounding Steinway and turning it into a glorious sounding Steinway.

I was in charge of the green room pianos at Tanglewood last summer, and the soloist room Steinway B at the main performance space transformed from my least favorite B on the grounds to my favorite one simply by lacquering the hammers. Prior to lacquering the hammers only had lacquer at the crowns and were otherwise pillow-soft. It sounded okay below mezzo-piano, but just ran out of steam as the dynamics increased, and lacked definition and clarity overall. After using a 7:1 acetone:lacquer solution on the shoulders (and the crown in the high treble) and letting it dry overnight, it was simply transformed. Big, full and clear sound with loads of color at all dynamic levels. Exactly what I love from a good Steinway.

That said, some pianos respond better than others. There was an M in one of the other green rooms that sounded even more anemic, and after lacquering with a slightly stronger solution, it was a significant improvement, but nowhere near the night and day difference that the B went through.

It also goes without saying that the technician has to be a good judge of tone and must be aware that it is possible to go too far. You certainly wouldn't treat the hammers on a home piano in the same manner as you'd treat the hammers on a concert grand in a large hall. And you definitely wouldn't want to soak the hammers to the point of losing their elasticity and spring (as Del mentioned above... that spring is crucial to well balanced tone).

If the hammers installed on a new piano were over-soft to the extent that they required chemical hardening then they were the wrong hammers for the piano.

ddf

I suppose. In an ideal situation I can definitely agree hammers that don't need chemical hardeners would be the better solution, both for the longevity of the hammers and the ease of maintenance. But, given the results that lacquering the hammers produced, I can live with the compromise.

Del,

Thank you for your thoughtful and detailed reply. As a piano designer, it seems to be from the perspective of where a piano begins, rather than after a few years of use. If I read your response correctly, you seem to be against any shaping or needling, also. Is that the case?

I'm trying to assess of this in the range of the techniques which may be employed to bring any given piano to its best possible voice.

Adam, I noticed a similar result on one of my students M&H-BB. The piano was only 4 y/o but had really dulled down. My reaction was; "What's wrong with lacquering the hammers if the results are so good?" The process brought back the solid sound of the Masons with a clean and clear top. It became a very satisfying piano to play.

Very good Del,

I see lacquering :

as a kind of voicing, with originally hammers lacking power in lower levels of play.
As a kind of voicing if the harmonic content is low (be it because of the piano or the hammers)
Then the power is raised in a linear way , as you state , exactly.
So the tone is "build" in a certain category of tone, with much presence at low levels, but less changes in its behaviour at forte.
That is well noticed in the comparison video kindly send by Sally Phillips.

Impregnation was also used on pressed hammers to
raise the power and protect the voicing against humidity.

But the tone is effectively always more linear then , I never find an exception even when the piano is pleasing to play.

Because the pianist can only manipulate the immediateness of the attack, and the after sound is soon in its high level dynamics, near saturation, while the resiliency of the attack with non impregnated hammers allows the pianist to "look for" the tone more deeply "in the hammer/key) IMHO

The initial problem is probably that we need much energy reflexion at FFF and that with optimum elasticity, and those are only the deepest layers of felt under the crown and around that allows for that .
I dont know if experiments have been made to locate the source of that sudden change in tone when the piano is played strong.

WIth impregnated hammers as on Steinways, that (plus the hard steel strings) allows for a true thunder like tone in basses.
But this cannot be obtained in mediums while it is possible with non impregnated hammers.

I wonder if that tone change is not due to a sudden horizontal polarization of the strings vibrations at a certain level. For it the string is possibly just under saturation. or the sounboard is pushed in lateral motion while the string is free enough to immediately rotates of its plane, or the hammer have some lateral motion that push the wire laterally , etc...

Good pianists like to have some time before that effect take place (some dynamic plague) . Some are lazy and like the piano to be colored by itself.

And many of the most recents pianos allow a less than good pianist to produce harmonious sounds without having to "shape" it from the keyboard.

Regards

As I have noted before, the frequency differential between the lowest note on a piano and the topmost note is a factor of 152. All else being equal (and it is not), one would have to have the lowest hammer remain on the string 152 times longer than the topmost note to have a similar response. This may not be possible with any material, especially with accuracy that one would like with a piano. How hammers are pressed may help, but it may not be the answer, either.

Lacquer turns wool felt into a hybrid material with some degree of control which can help deal with the problem, while needling alters the structure of the felt. Both may be desirable for certain effects.

The big problem is that hammers do not last as long as most people go without replacing them. So if you do something destructive to the hammers, it may not matter that much.

About longevity, the lacquered hammers are very long lasting because they are not deformed as much at every impact, and they do not suffer from moisture as much as the non impregnated ones.

But the very brilliant and clear tone obtained immediately after lacquer have dried can easily turn into a more limited dynamic tone with a too "square" behavior some time later - in medium range .... dosing and anticipating that is not exactly easy. I was said to play the impregnated hammers before the laquer dries to make it more homogeneous and even the hardening of the upper part -that can give an idea of how the sound will turn to.

When well done, the voicing is "fixed" for a very long time, the brilliancy anyway. Appreciable on some vertical pianos with a limited spectra.

Marty thanks for bringing a very important topic up. I hope the "bickering" does not get too "doped-up"!

Lacquering hammers is a very important tone-regulation tool for piano technicians. The options it allows are many and diverse. Knowing when and how to use lacquer on hammers is not easily or quickly gained because to judge the ultimate benefits of lacquering techniques take years of observation of pianos that you know what has been done to them.

Del makes a great point regarding destructive tone-regulation techniques but I think his statement is a little over generalized.

I do think Del's hammer measuring system, (can't we come up with a "magic" name for this?), shows great promise. It looks quite simple to do once the standards are developed.

I think having to needle a new set of hammers many, many times to bring the tone to a controllable state is ridiculous. Hammers made for this "voice-down" protocol do not wear well and change tone rapidly with use.

If you are tone-regulating a set of hammers made for the "voice-up" protocols you must employ shaping first before lacquer. Like most elements of a hand-fit assembly style-components start out oversize and are cut down to fit together best.

The hammer making process is full of steps where the felt is shaped by cutting so there is no reason some further cutting cannot be done after the set is installed.

Hammers do get work-hardened by use so when installing a new set understanding how much this will occur and how fast is very important knowledge only gained by experience.

If the tone is dull overall, shape the hammers by tapering the sides, (even narrowing the width sometimes), thinning the tails, Removing staple or wires, and "pear"-ing up the profile by using a knife to remove felt from the shoulders.

This should bring the tone of notes #1 to around #50 to a very good level of dynamics and brilliance.

If after this the treble is still dull-applying thin lacquer solutions works wonders from note #55 to #88.

These treble hammers, notes #55 to #88, require the least non-linear spring elastic behavior from the felt. So the "destruction" of this behavior is beneficial!

Lacquer also thins out with age so as the hammers get work-hardened by playing, the lacquer is getting weaker.

Properly done, "voice-up" hammers with judiciously applied lacquer will hold their tone for many years of serious playing. Plus the action will have less inertia and wear slower and feel better also.

No. Both of these techniques can be useful in some cases. I'm saying that the need for aggressive voicing of either type should avoided. In a new piano this requires close cooperation between a knowledgeable and skilled hammer department and the voicing technicians. Or, if the hammers are purchased from an outside vendor, it requires a thorough understanding of that vendor's offerings in order to find, or to specify, those hammers most appropriate to the needs of each piano model.

Obviously, these goals are not always met and there have been many—sometimes spectacular—failures over the past few decades. Hammers that are obviously too soft are still installed even though massive amounts of hardeners will be required to develop acceptable amounts of acoustic power. Or hammers that would rival granite on the hardness scale are fitted. It will then be up to the hapless voicer to turn them into more-or-less acceptable piano hammers. This requires creative, often aggressive, voicing. The end result will be—should be, anyway—a piano sounding less bad than it did prior to this voicing. Sometimes it’s a lot less bad. It is impossible to tell, however, just how the results of this voicing compares with how the piano might have sounded if more appropriate hammers been fitted from the start.

The same thing, of course, applies to existing pianos that are being fitted with new hammers. Every effort should be made by the technician, working with the piano owner, to select appropriate hammers for both the piano and the principle pianists. When this is done minimal voicing will be required to bring the piano up to its best voice. This requires that the technician have a personal working knowledge of each hammermakers offerings. Or at least the range of hammers offered by one or two hammermakers. And some technicians have worked hard to acquire this knowledge but it is all too common to hear something like, “I’m replacing the hammers on a 7’ Brand X piano and I need to know what I should use.” And then the answer, “Oh, I just replaced the hammers on my 5’ 2” Brand Y piano with Soandsuch hammers and they really sounded great.” Bah! Humbug!

Even with a good working knowledge of the available hammers and an understanding of the needs of a specific piano it is not usually possible match the two perfectly. We have, as yet, no method of accurately defining hammer performance so we must leave it to the voicer to refine the piano’s voice and make it into what we wanted it to be all along.

ddf

Well Ed, to me cutting the shoulders with a knife will turn the kind of hammers I work on in a damper, with the crown separated from the rest.

If it is possible with laquered hammers that proove how different the processes are. (I suppose anything is possible with laquered hammers as soon they are not "bricked".

[video:youtube]qeIEvCh5di8[/video]

I don't want to be crude, but the first piano is soon saturating when going "up in turns" and have the power raising very fast, most expressiveness locates in the immediateness then to me the "curve" is somehow flat , evened.

That said I have a young very good pianist that liked much the NY Steinway and pretended me that the shades of colors and dynamics where huge. She likes to manipulates a sparkling tone, also, and use to work on Yamahas.

the life in the aftersound is not very apparent in that video.


With the pressed hammers, we absolutely need the underlying power of a dense but natural felt all around the the underfelt or the tip. it seem to reflect in the ppp nuances as well, as I noticed using a drop of hardener at that point, it stiffens the felt and add a little power at FFF but the loss in dynamic quality for any other mode was sensible.

If SOS laquering is used it may leave the part around the molding untouched in my opinion it can allow the external of the hammer to "connect" better with the inner felt, but at the expense of the largeness of dynamics (nothing is free, never )

It is true that the attack is a little delayed, retarded, and the pianist may need to anticipates a bit, with some instruments. AT the same time the sensations provided are very good. and a whole palette seem to locate there.
Regards

He cites Neuhaus with good reason and demonstrates that flowering of notes very well !

That "delay" is what allows to play from the keybed/bottom of the key, while taking more height when playing fast.
What can be obtained "in the front punching is showing yet how much possibilities the hammers are providing.

My "gut feeling" is that it is made more use of the action resiliency with the German type of piano.


Regards

It is no surprise to me that so many technicians in USA prefer to tune OOO unison as the choice seem to be limited with moaning appearing soon in FFF playing due to the type of resilience of the hammers.
The tone is enlarged by the hammer more than by the tuning.

Still, in my opinion the "phase balance" between the 3 strings have to be established and happens naturally if not voluntarily.

Regards

Olek,
Thanks for the video. In it, the NY D on the pianists left, sounds better at balancing all the voices of the musical excerpts played. You can hear all the contrapuntal movement better.

Well ED I mean that is better for some kind of music certainly, the notes are well detached one another, have a definite shape.

(the actual Hamburg models is more for "grand public" than before, the tone is self corrected a little more on the cotoneous side, certainly, - needing some years to get to more active immediate sparkle) but the Aesthetics is and was really different, even with the precedent hammers up to the end of the 80's where the felt was denser and harder)


I just find it say on the "straight" side when it comes to the fine nuances needed for other music.

I liked much the extra sonorous of the basses and mediums of th NY models I played (very few) it gives a power and projection sensation at the tip of the finger. It comes at a cost, probably.


BTW I understand now why that tone can be so much suited for UT/Well temp. it easily sound as older pianos (when well prepped and that is the case here)

It would be interesting to hear from Sally how these pianos have been prepped and voiced. If the hammers are original, it's not only a nice comparison of NY vs. Hamburg, but the difference in concept of hammer design and voicing between the two.

I am making the assumption that the NY-D hammers have been lacquered as to company protocol.

This is a point I have been making in presentations on hammer making and voicing for years. But I am now revising my lecture outlines somewhat.

Whether or not cutting away the shoulders removes the foundation of the felt directly in contact with the strings in a way that significantly affects tone depends somewhat on the way the hammer felt is made. It is certainly true with highly layered felt that is lightly felted and then pressed to final thickness; less so with felt that is pounded—or felted—more. This seems to intertwine the wool fibers more, making it more difficult to pick out distinct layers of felt when sanding. It also seems to hold the foundation together a little better even if the hammers are sanded to shape. It certainly makes resurfacing them by hand sanding more difficult—in terms of piano tone this is probably a good thing.

With highly layered and pressed felt it is essential that the layers be kept intact. Cutting through them—as is done when hammers are pressed in a round shape and sanded to an oval or “pear” shape—definitely weakens the crown (or striking surface area) of the hammers and, as you say, quickly turns the crown of the hammer into a kind of damper. The only way to bring any semblance of voice back to these hammers is to chemically harden them. Chemical hardeners coat the wool fibers and “glues” them together, increasing the linear spring rate of the hammers. This will increase the (perceived) power and make the overall voice “brighter”—i.e., putting more energy into the shorter partials—but it comes at the expense of the effective non-linearity of the hammers.

Even with highly felted hammer felt it is still best, in my opinion, to mold the hammers to their desired proper shape rather than depending on subsequent cutting and/or sanding to get them there.

ddf

So much depends on the way lacquer is applied, and it is very difficult, if not impossible, to apply in a uniform manner. Since the solvent is highly volatile, the application will very from moment to moment, because the concentration of solids to solvent changes so rapidly.

I prefer to think of hammer felt as having "grain" orientation much like wood does. The grain orientation that most resists deformation from impact with the string is the preferred configuration.

The "layer" model just doesn't get me anywhere useful.

I suppose the ideal would be to make the hammer felt "curved"somewhat in the felt making press. That way when you glue it to the wood it would be less likely to split open and you could get it glued with more evenly applied stretching and compression. (Just made this up off the top of my head).

As is it now, the side shoulder cauls leave a bulge on the shoulder that is sanded or cut off.

I am listening at the moment Gershin concerto played at Julliard auditorium.

I absolutely understand how some people may find ET to be artificial and non expressive in that case.

The piano is not singing, the notes are very much detached one another, and then the congruence between intervals/octaves is really reduced.

The piano is "perfectly" tuned but the musical discourse is simply inexistent, harmonically speaking. Notes a lot of notes , well defined, but without particular resonance one another.

I hardly can put that on the hammers, but I am forced to recognize that those allalone notes does not help the pianist.
Plus so much presence always and always, from ppp to FFF (in fact at FFF it close and does not send much tone)

The tone is ideal at mf to F, not much more above.

UNison a little acid but that goes with the piano, they are "build" that way, it is a good tuning. The palette is "monochrome".
I remind many techs where mounting German hammers in NY Steiwnays.

Is it still the case ?

Regards

P.S. and now I listened to a nice impro played then on a Hamburg, (same concert) and I noticed how the technician treated the piano tuning the same as the NY one. so with a machine driven tuning, no much personality and limited palette despite the good pianist.
When listening I imagine myself playing that is how I know the level of pleasure that can be obtained.

With some couples pianos + tuning, you only can play notes and chords. Acceptable but not so enjoyable.

Possibly the musical references misses, the ear is accustomed and obliged to accept as the norm the general tone quality it is facing.