Pianotech

Nick,

Have you had success with flushing out excess B72? I have had a similar incident - my solution was too strong, and now I have too many solids in the hammer and a piercing sound. I am experimenting with a felt wedge which I have also juiced up with B72/acetone. I plan to apply more acetone to flush out some of the B72. Fortunately, I have only two problem hammers - worst case I can replace the hammers. I am curious about your experience.

Nick,

Have you had success with flushing out excess B72? I have had a similar incident - my solution was too strong, and now I have too many solids in the hammer and a piercing sound. I am experimenting with a felt wedge which I have also juiced up with B72/acetone. I plan to apply more acetone to flush out some of the B72. Fortunately, I have only two problem hammers - worst case I can replace the hammers. I am curious about your experience.

Nick,

Have you had success with flushing out excess B72? I have had a similar incident - my solution was too strong, and now I have too many solids in the hammer and a piercing sound. I am experimenting with a felt wedge which I have also juiced up with B72/acetone. I plan to apply more acetone to flush out some of the B72. Fortunately, I have only two problem hammers - worst case I can replace the hammers. I am curious about your experience.

Maria,

To me, a major benefit of B72 is that you disolve it in fairly harmless grain alcohol. Is there a good reason to use acetone, which I believe is fairly toxic to breathe? 

Nick,

Have you had success with flushing out excess B72? I have had a similar incident - my solution was too strong, and now I have too many solids in the hammer and a piercing sound. I am experimenting with a felt wedge which I have also juiced up with B72/acetone. I plan to apply more acetone to flush out some of the B72. Fortunately, I have only two problem hammers - worst case I can replace the hammers. I am curious about your experience.

Maria,

To me, a major benefit of B72 is that you disolve it in fairly harmless grain alcohol. Is there a good reason to use acetone, which I believe is fairly toxic to breathe? 

Nick,

Have you had success with flushing out excess B72? I have had a similar incident - my solution was too strong, and now I have too many solids in the hammer and a piercing sound. I am experimenting with a felt wedge which I have also juiced up with B72/acetone. I plan to apply more acetone to flush out some of the B72. Fortunately, I have only two problem hammers - worst case I can replace the hammers. I am curious about your experience.

Maria,

To me, a major benefit of B72 is that you disolve it in fairly harmless grain alcohol. Is there a good reason to use acetone, which I believe is fairly toxic to breathe? 

Nick,

Have you had success with flushing out excess B72? I have had a similar incident - my solution was too strong, and now I have too many solids in the hammer and a piercing sound. I am experimenting with a felt wedge which I have also juiced up with B72/acetone. I plan to apply more acetone to flush out some of the B72. Fortunately, I have only two problem hammers - worst case I can replace the hammers. I am curious about your experience.

Maria,

To me, a major benefit of B72 is that you disolve it in fairly harmless grain alcohol. Is there a good reason to use acetone, which I believe is fairly toxic to breathe? 

Nick,

Have you had success with flushing out excess B72? I have had a similar incident - my solution was too strong, and now I have too many solids in the hammer and a piercing sound. I am experimenting with a felt wedge which I have also juiced up with B72/acetone. I plan to apply more acetone to flush out some of the B72. Fortunately, I have only two problem hammers - worst case I can replace the hammers. I am curious about your experience.

Mssr. Lessard,

Much will depend on what sort of hammer the B 72 is in. In a soft American hammer one can listen string by string for harshness then use a single needle 4 or 5 mm long and voice the hammer right on the contact point for that string. In a hard European or Asian hammer a solution some have employed is to wet the strike point generously with acetone or lacquer thinner and then use compressed air to force the hardener out of the contact point. In either case the point isn't to soften the B 72 but to soften the tone.

Hi all,

Thanks for the advice! Maria, I did not experience the problem of applying too much hardener YET. (lol). However I did end up at some point with a slightly too crusty result and too near the strike point as I was hardening high shoulders, so I wondered how to correct that. So far, needling carefully with a single needle and our new "Mohawk sugar coater" prototype was satisfactory. Thanks to Dan Levitan for the concept.

Mssr. Lessard,

Much will depend on what sort of hammer the B 72 is in. In a soft American hammer one can listen string by string for harshness then use a single needle 4 or 5 mm long and voice the hammer right on the contact point for that string. In a hard European or Asian hammer a solution some have employed is to wet the strike point generously with acetone or lacquer thinner and then use compressed air to force the hardener out of the contact point. In either case the point isn't to soften the B 72 but to soften the tone.

Hi all,

Thanks for the advice! Maria, I did not experience the problem of applying too much hardener YET. (lol). However I did end up at some point with a slightly too crusty result and too near the strike point as I was hardening high shoulders, so I wondered how to correct that. So far, needling carefully with a single needle and our new "Mohawk sugar coater" prototype was satisfactory. Thanks to Dan Levitan for the concept.

Mssr. Lessard,

Much will depend on what sort of hammer the B 72 is in. In a soft American hammer one can listen string by string for harshness then use a single needle 4 or 5 mm long and voice the hammer right on the contact point for that string. In a hard European or Asian hammer a solution some have employed is to wet the strike point generously with acetone or lacquer thinner and then use compressed air to force the hardener out of the contact point. In either case the point isn't to soften the B 72 but to soften the tone.

What is the general strength people use?  I suppose I should experiment with this stuff since it seems to be the latest craze.  I just bought 100 grams.  In a 4 oz container (about 100 grams), how may grams of B-72 are used typically?  B-72 will dissolve in a variety of solvents from ethanol to acetone so I'll try both but would like a starting point.  Thanks

This is something I posted in January of 2019. The 4 gram in 4 oz mixture has been the most useful for me for several years now. YMMV.

Below is a picture from the first batch I mixed last Spring.  I used the mix suggestions on Dale Erwin's website. www.erwinspiano.com  I just wish I knew he sold B-72 before I bought mine as he sells the same quantity for half the price. I found that  1 teaspoon of the crystals was almost exactly 4 grams. Add that to 1/2 cup acetone  and it fits in a Gaunt hypo oiler 49 .

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Karl Roeder
Pompano Beach FL
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------------------------------
Karl Roeder
Pompano Beach FL
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-------------------------------------------

This is something I posted in January of 2019. The 4 gram in 4 oz mixture has been the most useful for me for several years now. YMMV.

Below is a picture from the first batch I mixed last Spring.  I used the mix suggestions on Dale Erwin's website. www.erwinspiano.com  I just wish I knew he sold B-72 before I bought mine as he sells the same quantity for half the price. I found that  1 teaspoon of the crystals was almost exactly 4 grams. Add that to 1/2 cup acetone  and it fits in a Gaunt hypo oiler 49 .

------------------------------
Karl Roeder
Pompano Beach FL
------------------------------

------------------------------
Karl Roeder
Pompano Beach FL
------------------------------
-------------------------------------------

Karl et al

In your experience does this product tend to get "pingy",  and are you having to needle out those pings rountinely?  

Chris

When you say it's "too soft not good for internal work" what do you mean?  I presume you mean for adequately building up the foundation of the hammer.  Do others find this to be true?  Personally, as far as stiffening agents go, I prefer something that is soft and remains flexible.  If it doesn't then any flexing of the hammer during the compression phase of the attack might tend to fracture the fiber which I prefer to avoid as I believe it shortens the life of the hammer and compromises it's integrity over time. Witness the powdery consistency that heavily lacquered hammers get at the crown over time.  That's the reason I avoid things like off the shelf lacquers, key top solution, sanding sealer. I can't comment on shellac but it would be a concern there too.  

This is something I posted in January of 2019. The 4 gram in 4 oz mixture has been the most useful for me for several years now. YMMV.

Below is a picture from the first batch I mixed last Spring.  I used the mix suggestions on Dale Erwin's website. www.erwinspiano.com  I just wish I knew he sold B-72 before I bought mine as he sells the same quantity for half the price. I found that  1 teaspoon of the crystals was almost exactly 4 grams. Add that to 1/2 cup acetone  and it fits in a Gaunt hypo oiler 49 .

------------------------------
Karl Roeder
Pompano Beach FL
------------------------------

------------------------------
Karl Roeder
Pompano Beach FL
------------------------------
-------------------------------------------

Mr. Love,

I've been using B-72 for 4 years or so because it has far less ping than other hardeners I've used. Pretty much any hardener I've tried will require some needling but a lot depends on the hammer and how close to the crown the hardener gets. I work on a lot of NY Steinways and take for granted that there is already lacquer in the hammer. A drop or two of B-72 on the crown is often all that is needed to make the difference I'm looking for. On a few concert grands in the last couple of years I've used B-72 in the 4gr/4oz strength between the top of the moulding and the crown 8 or10 drops on both sides of the hammer. The results have been quite good. I haven't found it too soft for internal work but Mr. Chernobieff may be looking for a different result than I am. I also have only used acetone as a solvent as I can't get pure ethanol in Florida. That may also make a difference.

Karl et al

In your experience does this product tend to get "pingy",  and are you having to needle out those pings rountinely?  

Chris

When you say it's "too soft not good for internal work" what do you mean?  I presume you mean for adequately building up the foundation of the hammer.  Do others find this to be true?  Personally, as far as stiffening agents go, I prefer something that is soft and remains flexible.  If it doesn't then any flexing of the hammer during the compression phase of the attack might tend to fracture the fiber which I prefer to avoid as I believe it shortens the life of the hammer and compromises it's integrity over time. Witness the powdery consistency that heavily lacquered hammers get at the crown over time.  That's the reason I avoid things like off the shelf lacquers, key top solution, sanding sealer. I can't comment on shellac but it would be a concern there too.  

This is something I posted in January of 2019. The 4 gram in 4 oz mixture has been the most useful for me for several years now. YMMV.

Below is a picture from the first batch I mixed last Spring.  I used the mix suggestions on Dale Erwin's website. www.erwinspiano.com  I just wish I knew he sold B-72 before I bought mine as he sells the same quantity for half the price. I found that  1 teaspoon of the crystals was almost exactly 4 grams. Add that to 1/2 cup acetone  and it fits in a Gaunt hypo oiler 49 .

------------------------------
Karl Roeder
Pompano Beach FL
------------------------------

------------------------------
Karl Roeder
Pompano Beach FL
------------------------------
-------------------------------------------

Mr. Love,

I've been using B-72 for 4 years or so because it has far less ping than other hardeners I've used. Pretty much any hardener I've tried will require some needling but a lot depends on the hammer and how close to the crown the hardener gets. I work on a lot of NY Steinways and take for granted that there is already lacquer in the hammer. A drop or two of B-72 on the crown is often all that is needed to make the difference I'm looking for. On a few concert grands in the last couple of years I've used B-72 in the 4gr/4oz strength between the top of the moulding and the crown 8 or10 drops on both sides of the hammer. The results have been quite good. I haven't found it too soft for internal work but Mr. Chernobieff may be looking for a different result than I am. I also have only used acetone as a solvent as I can't get pure ethanol in Florida. That may also make a difference.

Karl et al

In your experience does this product tend to get "pingy",  and are you having to needle out those pings rountinely?  

Chris

When you say it's "too soft not good for internal work" what do you mean?  I presume you mean for adequately building up the foundation of the hammer.  Do others find this to be true?  Personally, as far as stiffening agents go, I prefer something that is soft and remains flexible.  If it doesn't then any flexing of the hammer during the compression phase of the attack might tend to fracture the fiber which I prefer to avoid as I believe it shortens the life of the hammer and compromises it's integrity over time. Witness the powdery consistency that heavily lacquered hammers get at the crown over time.  That's the reason I avoid things like off the shelf lacquers, key top solution, sanding sealer. I can't comment on shellac but it would be a concern there too.  

This is something I posted in January of 2019. The 4 gram in 4 oz mixture has been the most useful for me for several years now. YMMV.

Below is a picture from the first batch I mixed last Spring.  I used the mix suggestions on Dale Erwin's website. www.erwinspiano.com  I just wish I knew he sold B-72 before I bought mine as he sells the same quantity for half the price. I found that  1 teaspoon of the crystals was almost exactly 4 grams. Add that to 1/2 cup acetone  and it fits in a Gaunt hypo oiler 49 .

------------------------------
Karl Roeder
Pompano Beach FL
------------------------------

------------------------------
Karl Roeder
Pompano Beach FL
------------------------------
-------------------------------------------

I experimented with a felt mute that I had doped with Acetone/B72 heavy mixture. I cut the hardened mute into to parts. I soaked one half of it in B72, and left the other half untouched so I can compare them. After 10 minutes of soaking the mute in Acetone, it had washed out much of the hardener. It was more flexible than an untreated hammer, but less elastic.

I had overhardened two hammers of a Kawai upright. I removed the hammers and soaked them in Acetone for 13 minutes. The hammers became penetrable and I was able to needle them down to a pleasant strong tone and blend the break at this upright Kawai. It took quite a bit of needling. The 'gummi-ness' of B72 took me a little to get used to. But I really liked the texture of the hammers after I had the right amount of solids in the hammer.