CAUT

  • 1.  Hardening hammers in the upper treble

    Registered Piano Technician
    Posted 04-19-2018 07:54

    Just out of curiosity, and because US tech experience when it comes to hardening hammers is so much greater than mine:

    If you brighten the highest treble by using plexi/acetone or lacquer/thinner, do you prefer to apply it to the sides of the hammers or directly on the striking point? I've heard reasoning for and against both, so my guess is that the camp is divided on this one.

    I've tried both myself -- instant results applied to the striking point, easily overdone, wears fast. Slower procedure treating the sides, more control, lasts longer.

    The reason I ask this right now is that I'll treat a Fazioli 278 this week. It has new hammers, and when you play up through the treble, it's like somebody's gradually closing the lid :) 

    Some techs here in Europe refuses to use any kind of hardener at all, advocating playing the a lot to gain more prominent upper partials, especially in the treble. That is all good and well, but this piano needs to be ready for use immediately. The intonation in other ranges needs some work, too, but the treble is by far the most important issue right now.



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    Patrick Wingren, RPT
    Jakobstad, Finland
    0035844-5288048
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  • 2.  RE: Hardening hammers in the upper treble

    Registered Piano Technician
    Posted 04-19-2018 10:14
    For densely pressed hammers, my use of hardeners is generally limited to acetone/acrylic, and is fairly thin and applied sparingly to the crown where needed, maybe three drops per hammer (apply again if needed). This is then usually sanded very lightly with fine paper to remove the strident sound. I find this treatment will give  the piano the needed attack sound, and that as it wears through, the lower, denser layers of felt will take over. It is something I usually do for new pianos and for new hammers I have installed, if needed, mostly so the piano will be ready to go in a concert situation, and I have been quite satisfied with the results. You could probably get the same through filing, but why wear through hammer felt unnecessarily?

    If the felt is not dense enough, from being pressed more lightly (or possibly from having been over-needled), my approach is to apply lacquer from the sides, right at the tip of the molding, saturating a circle centered on the tip of the molding, not reaching the surface. But that is a different issue, compensating for lack of density rather than adding a little bite to the attack.
    Regards,
    Fred Sturm
    "When I smell a flower, I don't think about how it was cultivated. I like to listen to music the same way." Mompou






  • 3.  RE: Hardening hammers in the upper treble

    Registered Piano Technician
    Posted 04-19-2018 10:43
    Hi Pat-

    What ratio of mixing do you generally hear being suggested there, or what mixture did you try?  That is another very important variable. If you want to proceed relatively easy and safe try a very light mixture first, which seems to me might be appropriate on a piano like that anyway. I think most of us in the US apply directly to the crown for at least the top octave, then start tapering down the shoulders for the next octave or 2 or 3, as needed.  First application of a thin mixture (6 or 8 to 1) will absorb deeper into the felt where you want it, and you can always add a stronger mix later if needed. From my experience, thicker solutions work better for more precise applications of a few drops to specific target areas of the hammer, after my initial thin dosing.  As you probably know, the lacquer solution gradually breaks down somewhat, as opposed to plexi, as the hammer gets played in, which may be another consideration.  No doubt there are other successful methods too. 

    best,

    Dennis Johnson
    St. Olaf College





  • 4.  RE: Hardening hammers in the upper treble

    Registered Piano Technician
    Posted 04-19-2018 12:24
    This is a great point. Although I am very anxious to try B-72 (or whatever the exact term is) which has great potential-reference: Dale Erwin & others), I am still using water white laquer & acetone-traditional Steinway "juice". The 3 strengths that were recommended to me by one of the main Steinway techs in Texas are: 3:1 strong, 6:1 medium and 12:1 light. This is just a starting place but I have found this to be VERY practical in real life. I had to build up several brand new Steinway model Os recently & I ended up using 10:1 for a lighter mix as 12:1 just sort of "pops the brightness" a bit (great for very fine voicing!)
    But about 5 or 6 to one was super helpful for building the tone for my situation. I DID do some side voicing first as Fred described one particular problem child, but I think I used 4 to 1 which I feel good about and it worked well. 
    We get our Water White Laquer from Kelly Moore-my gallon was about 38 bucks. (This is a thing for several chapter members to "go in on" because a gallon is a TON of product!)

    ------------------------------
    [Kevin] [Fortenberry] [RPT]
    [Staff Techician]
    [Texas Tech Univ]
    [Lubbock] [TX]
    [8067783962]
    ------------------------------



  • 5.  RE: Hardening hammers in the upper treble

    Registered Piano Technician
    Posted 04-23-2018 16:50

    Fred, Dennis, Kevin:

    Thanks for sharing your knowledge! I went with acrylic/acetone for the Fazioli, 1-2 teaspoons in 150 ml (should be close to 5 oz), carefully applied directly to the crown. Erring on the safe side, I started with a few drops all the way down to A#5 -- quite low, but that's where I started to notice a decrease of brilliance in the tone.

    I returned the next day, and then did the same thing once again for about the last 1 1/2 octave. A little bit of sanding and needling, and it all worked out very well - I can't hear any obvious transitions now.

    I might apply a third round to the very highest notes. I don't know if you're familiar with the Fazioli 278's, but they have a crazily long decay time -- the sound resonates forever, it seems. Thus, I've always felt that they need a brighter attack than a Steinway D.

    I'll have to do a side-by-side test with these two grands at some stage; same loudness, measure decay. If somebody hits a ff chord on the Fazioli, I bet you could go for lunch and return just in time to hear the tail of the decay :) :) 



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    Patrick Wingren, RPT
    Jakobstad, Finland
    0035844-5288048
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  • 6.  RE: Hardening hammers in the upper treble

    Registered Piano Technician
    Posted 04-23-2018 16:53

    Oh, and by the way, is there any particular explanation to why acrylic is almost always paired with acetone, and lacquer with thinner? Or is it just tradition, and the fact that it works? 

    Kevin: what is water white lacquer used for "normally"? Sounds like a good option, I only have shellac over here. 



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    Patrick Wingren, RPT
    Jakobstad, Finland
    0035844-5288048
    ------------------------------



  • 7.  RE: Hardening hammers in the upper treble

    Registered Piano Technician
    Posted 04-23-2018 18:16
    You can thin lacquer with acetone, and it will dry faster. Some think the faster drying is counterproductive. I have no opinion on that.

    I'm not sure how well lacquer thinner will dissolve acrylic, but in general, I think the idea with acetone and acrylic (originally acetone with a plastic keytop instead of plexiglass) was to have something that is virtually instant, that you can do with as little as half an hour lead time or even a bit less, and get audible results that are close to what they will be over night. Acetone is the fastest to evaporate, while lacquer thinner has other solvents to slow the evaporation. Lacquer will already have those slower flashing solvents in it, so using it with acetone will speed hardening, but it will still take a good bit longer to get final results.

    It is also possible to use acetone alone on a lacquered hammer to brighten it - it dissolves some solids, and flashes off at the surface, leaving something of a concentration of solids at the surface. Some say acetone will brighten a hammer that has no hardener in the felt, but I have never tried that.
    Regards,
    Fred Sturm
    "I am only interested in music that is better than it can be played." Schnabel






  • 8.  RE: Hardening hammers in the upper treble

    Registered Piano Technician
    Posted 04-24-2018 15:36

    Thanks again, Fred!

    BTW, my mind slipped earlier, the lacquer i have here is nitrocellulose, not shellac.



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    Patrick Wingren, RPT
    Jakobstad, Finland
    0035844-5288048
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  • 9.  RE: Hardening hammers in the upper treble

    Registered Piano Technician
    Posted 04-24-2018 19:15
    Yes! That's it. That is what we use. (Shellac is also READILY available but it is very different and is thinned with alcohol I believe). 
    It is handy for brushing a bit of quick drying finish on bridge notches by the way. It is typically available in regular and "Amber" here which is nice on older soundboards. No extra charge for this random tip.

    ------------------------------
    [Kevin] [Fortenberry] [RPT]
    [Staff Techician]
    [Texas Tech Univ]
    [Lubbock] [TX]
    [8067783962]
    ------------------------------