There is also a hammer softener solution for sale that you simply apply to the hammer, it doesn't have to be dipped in it. I'd follow it with some needling under the strike point, not straight in but from shallow angles coming from the front or back. Judiciously.
However, if these hammers are pretty old, replacing seems the much preferred option and I'll explain below how to apply hardener so as not to cause this situation again in a new set of hammers.
I'd also file the hammers and tidy up regulation and hammer travel / string mating first. Or confirm that all of this is in good shape. It's important to proceed this way rather than using voicing techniques to cover a lack of good foundational prep.
The issue I found with steaming hammers is that due to the reduction of density of the felt from steaming, hammer wear and deep string grooves were accelerated rapidly to the point of premature hammer destruction.
For the Acetone rinse I angle the action so that the hammers can drop nose-down into long, narrow trays. I have chicken feeding tins that serve the purpose.
That being said, I have also found the Acetone wash also to be not entirely effective. And having to leave that much solvent to evaporate is a problem for a lot of spaces, even at a small shop.
I've also applied solvent to the nose of hammers and then struck the key to send the hammer upward to strike a block of wood. The reasoning being to drive hardener away from the strike point.
It is also worth noting that steaming a high tension hammer versus a low tension hammer will be different. And, the technique. Note that Kathy's description of steaming is the application of a very narrow, damp strip of cloth followed by the iron. That is a highly-controlled application. With highly-limited moisture, I think there is less risk of high hammer wear but it probably depends in the condition of the felt, how much it was needled and how much use the piano will have.
The hammer softener in the bottle is something I've found effective. And it's not a harsh solvent. If I remember, I may have used it in staged applications to control the result. And it might have more of an effect on one style of hammer over another.
Here's how I'd apply hardener to new low-tension style hammers:
To accomplish this and still find needed brilliance in the treble, all the technician must do is build tone by applying lacquer low at the shoulders without flowing hardener into or directly under the strike point. And then, apply hardener, a lighter dilution, in the tiniest of drops to the individual string strike points where desired.
That minimal application in my opinion is less likely to develop into the difficult situation of a Steinway piano with harsh tone, from a solid hammer full of lacquer everywhere.
Also, if perchance a hammer should become too bright at the strike point with the minuscule drops of hardener application, I do not believe it will be too difficult to remove that hardener should it be necessary. But over time, that tiny bit of hardened area can also wear away in theory. At which point, the hammer will have likely also matured and have more compacted felt at the strike point, maintaining its tone. Yet without an excess of hammer hardener.
Kind regards.
Tom Wright, RPT
1-240-383-9345
Original Message:
Sent: 7/14/2026 2:23:00 AM
From: Mario Igrec
Subject: RE: steaam over-lacquesred hammers?
I would acetone-wash softer hammers rather than steam them, which can distort the felt and give it bulges.
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Mario Igrec, RPT, MM
Chief Piano Technician, The Juilliard School
http://www.pianosinsideout.com
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