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Paraloid B72 as hammer hardner

  • 1.  Paraloid B72 as hammer hardner

    Posted 01-30-2019 17:45
    I have purchased and want to try using Paraloid B72 as a hammer hardener.
    The package says 95% acetone mixture for consolidating or reinforcing
    plaster like materials.

    What does anyone using this for hammers use as a proportion for hammer
    hardener?

    ------------------------------
    Dave Conte
    Owner
    North Richland Hills TX
    817-581-7321
    ------------------------------


  • 2.  RE: Paraloid B72 as hammer hardner

    Posted 01-30-2019 18:34
    Edited by Karl Roeder 01-31-2019 19:41
    Mr. Conte,

    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 .
    thumbnail image


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



  • 3.  RE: Paraloid B72 as hammer hardner

    Posted 01-31-2019 10:01
    Apologies to anyone who read my original post. I have since edited it to correct mistakes in the mixture quantities.

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



  • 4.  RE: Paraloid B72 as hammer hardner

    Posted 01-30-2019 18:43
    Dave

    if you bought this from Irwin, directions come with the material.  I have them at home and can get them to you tonight, if you still need them.

    ------------------------------
    Willem "Wim" Blees, RPT
    Mililani, HI 96789
    ------------------------------



  • 5.  RE: Paraloid B72 as hammer hardner

    Posted 01-31-2019 00:34
    Thanks, Wim.

    I don't remember where I found out about this material, but it
    was on a forum someplace. I ran across some from a chemical
    producer before I learned that Dale had it. Thanks to Karl
    and to John Granholm for the heads up on this. It's so great
    when we all work together.


    ------------------------------
    Dave Conte
    Owner
    North Richland Hills TX
    817-581-7321
    ------------------------------



  • 6.  RE: Paraloid B72 as hammer hardner

    Posted 01-31-2019 03:18
    I have a small bottle of "hardener" that is mixed as 1 gram of Paraloid to 100 ml of acetone (about a 1% solution).  I find it amazing that even at this low concentration it is quite effective as a hardening solution that easily brightens hammers up.  This solution is less likely to get me in trouble than thicker solutions and it can be re-applied to increase brightness.  Less is better.

    The acetone dries quicker.  Be very careful that the heat from your fingers doesn't cause an eyedropper to squirt unexpectedly (AMHIK).

    I have not yet experimented with using alcohol as a solvent.

    ------------------------------
    Blaine Hebert
    Duarte CA
    626-795-5170
    ------------------------------



  • 7.  RE: Paraloid B72 as hammer hardner

    Posted 01-31-2019 07:55
    Ken Eschete's article will appear in the March Journal.
    He recommends alcohol because it does not pull the lacquer to the surface as it evaporates.
    It does take much longer for the pellets to dissolve in alcohol, and 200 proof grain alcohol is not available in all states.
    Denatured alcohol can be used, and I've used 99% isopropyl alcohol.
    It is also possible to dissolve the pellets in a small amount acetone and then dilute with alcohol.
    This material seems very forgiving to work with. The general approach seems to be putting a very thin solution near the strike point and thicker solutions below the shoulder, on the staple.
    I'll have an interesting test today, and perhaps a report later: I like the piano as it is, but the customer wants it "voiced up."

    ------------------------------
    Ed Sutton
    ed440@me.com
    (980) 254-7413
    ------------------------------



  • 8.  RE: Paraloid B72 as hammer hardner

    Posted 01-31-2019 13:43
    Ed,  How long does the alcohol take to give an accurate "reading" of what you've got?  One of the big benefits I find with the acetone, is when bringing soft hammers up, which is the way I prefer to work, on-site, you get an amazingly fast tonal read. This curing time issue, previously, had been the bane of my on-site juicing protocol, as coming back the next day is just too expensive and cumbersome.

    ------------------------------
    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026
    ------------------------------



  • 9.  RE: Paraloid B72 as hammer hardner

    Posted 01-31-2019 14:34
    Well, today was my first use of paraloid B72.
    I used a very thin solution in 99% isopropyl alcohol.
    I dipped a strip of paper towel in the solution and let it dry. It was just slightly stiffer than the plain towel.
    The piano was a 1950 Steinway D in a home. The customer wanted more power in the capo sections.
    The piano had Steinway hammers, lacquered and beautifully voiced by a better tech than me.
    But I could see the complaint. D5 and up didn't "gain."
    I ran a line of the solution just to the front and back of the strike points.
    Fifteen minutes later I tested and liked what I heard.
    Thirty minutes later I liked it very much. There was a little bit of ping, not enough to break up the tone, and the power carried across the capo section. Triads in octave 5 and 6 could be heard clearly over octaves in the bass, they didn't get swallowed up.
    I didn't do any smoothing out. I see this piano often.
    The customer is 5 miles away, so I left, telling him to call if it gets harsh.

    ------------------------------
    Ed Sutton
    ed440@me.com
    (980) 254-7413
    ------------------------------



  • 10.  RE: Paraloid B72 as hammer hardner

    Posted 01-31-2019 14:45
    so the alcohol doesn't seem to slow it down enough to be problematic. That's good, as the acetone stinks beyond stink-a-tude.

    ------------------------------
    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026
    ------------------------------



  • 11.  RE: Paraloid B72 as hammer hardner

    Posted 01-31-2019 15:04
    Well, we'll see if the customer calls me back, and what it sounds like when I go back to tune in March.

    ------------------------------
    Ed Sutton
    ed440@me.com
    (980) 254-7413
    ------------------------------



  • 12.  RE: Paraloid B72 as hammer hardner

    Posted 01-31-2019 21:27
    I have never tried paraloid B-72, and thought I'd share my reasons why.

    First, I looked at its chemical makeup. It is an acrylic resin, virtually identical to the one used in Plexiglass, which we can buy ground up from Pianotek as powdered hammer hardener, commonly (but erroneously) referred to as "key top."

    So I asked Ken Eschete what was the difference. He said that the results would be essentially identical, if you dissolved each in acetone. The one and only reason he advocates using B-72 is the fact that it dissolves (eventually) in alcohol. The reason he wants something that dissolves in alcohol, is that more of it remains within the interior of the material (hammer felt in this case) than with the faster evaporating solvent, something that was confirmed in a scientific study he had seen (I think he linked me to the article).

    I'll note that it was Ken, and only Ken, who initiated the use of B-72 - it is a substance used in conservation work, which is how he learned about it.

    I mostly use acrylic in acetone for light surface crown application, to give a bit more bite to the attack. If that results in "zing" (from solids on the surface due to the evaporation), it is easily and quickly remedied by running a strip of very fine sandpaper over the felt. But most often, at the concentration and amount I apply, that isn't necessary. If I need to apply it two or three times to some hammers, that's when I sand a bit.

    For deeper application of hardener, I have long since converted to applying it not to the surface of the hammer, but to the side, right at the point of the molding. I apply to both sides, and avoid applying enough to reach the rounded surface of the hammer. (For anyone who wants the hardener in the shoulders, that is easy to do from the sides as well). Hence, I have no problem getting my hardener into the interior of the material, or of it flashing toward the surface (it may flash to the cut sides of the hammer, but that is harmless).

    Furthermore, if I should want to apply a hardener in a solvent that flashes more slowly, like alcohol, I have extra blond shellac flakes, which dissolve quite readily in alcohol.

    So I see no need to substitute a new material, more exotic, expensive, and somewhat more difficult to come by, that is also quite difficult to get to dissolve in alcohol, as explained in some detail in Ken and Dan Levitan's class at Lancaster last summer.

    This is not to dispute whether or not it is a good thing to use, but simply to provide another perspective for those readers who haven't made the plunge.

    ------------------------------
    Fred Sturm
    University of New Mexico
    fssturm@unm.edu
    http://fredsturm.net
    http://www.artoftuning.com
    "We either make ourselves happy or miserable. The amount of work is the same." - Carlos Casteneda
    ------------------------------



  • 13.  RE: Paraloid B72 as hammer hardner

    Posted 01-31-2019 21:55
    But Fred,

    "Paraloid B-72" sounds so much cooler and sophisticated than "acrylic keytops".  That's an overriding reason to use it. 😎

    Pwg

    ------------------------------
    Peter Grey
    Stratham NH
    603-686-2395
    pianodoctor57@gmail.com
    ------------------------------



  • 14.  RE: Paraloid B72 as hammer hardner

    Posted 01-31-2019 23:27
    Plus, clear Paraloid B-72 doesn't contain white pigments or fillers like
    keytops.




  • 15.  RE: Paraloid B72 as hammer hardner

    Posted 01-31-2019 23:56
    Nor does acrylic, as in ground up plexiglas.
    Regards,
    Fred Sturm
    "Since everything is in our heads, we had better not lose them." Coco Chanel






  • 16.  RE: Paraloid B72 as hammer hardner

    Posted 01-31-2019 22:09
    Thank you Fred for your explanation!
    Peter

    ------------------------------
    Petrus Janssen
    Peachtree City GA
    678-416-8055
    ------------------------------



  • 17.  RE: Paraloid B72 as hammer hardner

    Posted 02-01-2019 07:17
    Fred-
    Paraloid B72 costs $12 for a half-pound at TALAS.
    If you can't wait for it to dissolve in alcohol, dissolve it in a small amount of acetone, then dilute with alcohol. The acetone odor is much reduced.
    As I mentioned, 99% isopropyl alcohol from a drug store works as a solvent.
    Unlike plexiglas, paraloid remains flexible when solid. It is also useful as an adhesive.
    Some respected and experienced colleagues have stated their preference for this material.
    I suggest you consider an actual trial before pronouncing judgement.

    ------------------------------
    Ed Sutton
    ed440@me.com
    (980) 254-7413
    ------------------------------



  • 18.  RE: Paraloid B72 as hammer hardner

    Posted 02-01-2019 08:55
    Edited by Jim Ialeggio 02-01-2019 08:59
    regarding Ken's preference for alcohol becasue it draws the product further into the felt, another way to achieve this penetration, which I got from Ed Mcmorrow, is to simply douse area with pure whatever solvent is in your juice, then apply the juice. I don't find I need to do this in the high treble, but lower down, where I am looking for very minor gradations of change, I like it. Though, still I will experiment with b-72/alcohol.

    ------------------------------
    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026
    ------------------------------



  • 19.  RE: Paraloid B72 as hammer hardner

    Posted 02-01-2019 09:37
    Jim-
    The sense I got from Ken's explanation was not that alcohol draws the resin deeper into the felt than acetone, but rather that in the process of evaporating, the acetone draws the resin back up to the surface, but alcohol does not.
    You'd have to ask Ken to be sure.

    ------------------------------
    Ed Sutton
    ed440@me.com
    (980) 254-7413
    ------------------------------



  • 20.  RE: Paraloid B72 as hammer hardner

    Posted 02-01-2019 12:45
    Ed,
    I am not passing judgment, and was careful to note I haven't tried B72. I am also quite aware that several colleagues whom I respect are using it. 

    I am simply raising questions. I am not at all clear that B72 is either more or less flexible than plexiglass, as plexiglass has a definite flexibility to it (hence its use as a glass substitute). I believe "keytop" (probably pyralin, initially, but others have probably been used as well) tended to be more flexible, and that this was considered a drawback by some, including myself. 

    B-72 is an ethyl-methacrylate polymer, while plexiglass is a methyl methacrylate polymer - somewhat different, chemically, but how different and in what ways that would be applicable to use as a hammer hardener? In reading about each substance, nothing strikes me as being essentially different in ways that would affect that use.

    Ken Eschete first started using it about ten years or so ago. At some point, as I said in my previous post, I asked Ken Eschete, and he was unaware of any particular benefit vis-a-vis plexiglas in acetone, beyond not needing a toxic chemical to dissolve, and the lower flash rate of alcohol leaving more of the solute within the material. I don't know whether or not he has modified his opinion.

    A couple years back, Dale Erwin heard about B72, became enthused, and started carrying it and promoting its use. He simply dissolves it in acetone, and that is what he advises. So we have mixed messages from different directions. 

    In our business, there is a lot of reliance on authority: "So and so uses this, does it that way, so it must be good." And stories get distorted so that details of the original technique, product, whatever, get lost. I remember being told how wonderful voicing with glovers needles was. I also remember a lot of strange claims for the wonders of Profelt, with people using it to voice hammers, and thinking/claiming it would firm up action centers.

    So I am playing devil's advocate, in the hopes of sparking conversation about the basics, rather than just "I heard so and so did it this way" conversations. I'll ask you, Ed, whether you are convinced that your own recent experiment with B72 had significantly different results from the same procedure with plexiglas dissolved in acetone. If so, in what way was it different?

    No disrespect meant to anyone. I ask questions and present contrary opinions in order to learn.






  • 21.  RE: Paraloid B72 as hammer hardner

    Posted 01-31-2019 08:18
      |   view attached
    I attached a word doc that has mixing protocols as described by Dale Erwin, Ken Eschete and Del Fandrich. Take your pick. I've yet to pick up some ethanol, but plan on doing that soon, though I have been quite pleased so far with the results using acetone.


    ------------------------------
    Adam Schulte-Bukowinski, RPT
    Piano Technician
    Glenn Korff School of Music
    University of Nebraska at Lincoln
    ------------------------------

    Attachment(s)

    docx
    B72 Mixing Methods.docx   14K 1 version


  • 22.  RE: Paraloid B72 as hammer hardner

    Posted 01-31-2019 11:26
    I bought mine from a Canadian conservation supplier as it seems Dale doesn't ship it to Canada (as I recall). I used the instructions here: (click to see the site from Bentside Arts)

    Rather than using acetone I prefer a "rectified spirit" like Everclear and use a transfer pipette to apply it as per the instructions. So far I've been quite pleased with the results.

    I made up full-strength and half-strength and keep it in the tiny plastic liquor bottles like you get on airplanes. I carry Protek and Profelt in similar bottles but have a different shaped bottle for each liquid. All bottles are labelled with a Brother Label Maker so I know what's actually in them!



    ------------------------------
    John Musselwhite, RPT
    Calgary, AB Canada
    www.musselwhite.com
    ------------------------------



  • 23.  RE: Paraloid B72 as hammer hardner

    Posted 01-31-2019 18:08
    Since alcohol is hygroscopic, I wonder if the addition of water to the mix helps mitigate the hardening action slightly.

    Pwg

    ------------------------------
    Peter Grey
    Stratham NH
    603-686-2395
    pianodoctor57@gmail.com
    ------------------------------



  • 24.  RE: Paraloid B72 as hammer hardner

    Posted 02-12-2019 23:05
    Hello All-  I'm late to the party as usual.  Unfortunately, my reading habits are such that I don't read this blog regularly.  My experiences with acrylic resin may be useful to some of you.  I was first introduced to Paraloid B72 (then called Acryloid) in 1978 in a paleontology class.  We used it for consolidating fossils by  applying it with paint brushes.  B72 was purchased in pre-mixed liquid resin form. There was also a powdered version that dissolved quickly.  However, I don't think it was B72 resin.  There are dozens of Paraloid resins with varying properties. There's also a line of "A" resins.   Much info on B72 can be gleaned from paleontology and museum conservation web sites.  I never thought much about Paraloid resins until 1989 when I was re-introduced to it while learning gold leafing in New York City in the Metropolitan Museum of Art.  It is used in the art world to consolidate decomposing gesso (among countless other uses). I restored a 1903 gold leafed Steinway B that was on the cover of the PTJ in 2001.  The piano had a few areas of gesso under the gold that were strengthened with B72.

    Up until the 1990's I used nitrocellulose (NC) lacquer and occasionally shellac for voicing hammers. I once spent a day learning "lacquer voicing secrets" from Raymond Parada, one on one, in his office in the Steinway factory. He was "The Man" for a long time. They weren't really secrets, just the tried and true methods.  NC lacquer voicing is a perfectly legit method of voicing so don't believe all the bad press.  Also, the definition of a quality hammer is not based on the presence or absence of hardeners.

    In the early 90's I began experimenting with B72 for voicing but had a limited supply. This was before the days of the internet.  Because of price, availability, the preparation hassle and inconvenience of Paraloid B72,  I just quit using it when it ran out.  It's great that it is now readily available to us. The results were excellent and I preferred it over NC lacquer.  I had a limited amount of experience using it for voicing.  Probably only 4 or 5 sets of hammers.   There are lots of sources for acrylic resin. I have a dedicated spray room in my shop and have always used Sherwin-Williams products for refinishing, mainly because of availability.  I found that their "Moisture Resistant Lacquer" was a good source for a Paraloid B?? acrylic resin for voicing. The problem with lacquers has always been in knowing the "percent solids". This is eliminated with B72 as it is 100%.

    The entire purpose of all this rambling is to present a new protocol for juicing up hammers.  For at least twenty years I have been using two types of resin for voicing and have proven them over and over.  I've never heard of this before but I'm sure that somebody, somewhere has to have had the same idea. There are a lot of smart technicians in the PTG with thousands of years of experience.

    The first is an acrylic syrup.  I dissolve it in MEK or acetone.  In MEK it's ready to go in less than 5 minutes and in acetone about 10-15 minutes. It is used just like Paraloid B72 or acrylic or NC lacquer, or keytop or hammer hardener from supply houses.  It also cheap and readily available. This is just acrylic cement; aka: good ol' sniffin glue.  Don't worry, it's no more dangerous than any of the other voicing solutions. It can be purchased locally and has a long shelf life.  It can be mixed by weight or volume.  For every gram of resin I'll mix 5-10-15 or whatever grams of solvent, or drops or eyedroppers or tablespoons.  I've never been too worried about exact ratios.  I just think of the solutions as weak, medium, or strong.  This isn't rocket surgery.  It is always amusing when people agonize over whether to use a 1:8 or a 1:9 solution. The type of alcohol is not important. Methyl is the hottest, then ethyl, then propyl.  A can of hardware store denatured alcohol is all you need in the shop. It is mostly ethanol, denatured with methanol. If you need something hotter, such as for French polishing shellac, then you can buy straight methanol. Otherwise, a few seconds difference in flash time isn't going to matter. (The flat areas of the gold piano were French polished with methanol.)  Just stay away from rubbing alcohol as it contains 30% water.  BTW- isopropyl alcohol is not necessarily rubbing alcohol.   Water will affect the resin and you definitely don't want to be pouring water onto felt that you're trying to harden.  Water doesn't dilute alcohol; alcohol dilutes water.

    The brand of acrylic glue I buy is Weld-On #16 for Acrylic Sheet.  I'm sure there are other brands that will work just as well. Acrylic syrups vary from approximately 70% to 90% resin, so get the the good stuff.  From my observations over the years it seems to be slightly harder than B72.  I have no data or done any testing so I'm just throwing this out there for whatever it's worth.  Also, I've never used the granules from the supply houses and the last time I used keytop was thirty years ago.  BTW, we occasionally hear of "collodion" used as a voicing solution in Europe. I've never used it. (What is sold today as a cosmetic is not the same stuff.) It has developed a sort of romantic aura about it, possibly because it is banned in the U.S. or that we imagine that it would give us that perfect elusive, magical tone if we could only get our hands on it.  It is nothing more than nitrocellulose resin dissolved in ether and alcohol.  It's probably one of the more dangerous concoctions in the shop.

    The second voicing resin is my favorite and I use it almost exclusively.  It is pure vinyl resin -PVC.   This is sold as clear PVC cement that is used for connecting white PVC rigid pipe for plumbing and irrigation. It uses MEK as a solvent which stinks to high heaven.  It can be thinned with acetone or alcohol for less smell.  It also comes in a low VOC version which I have not tried.  It is great for the wholesale soaking of new sets of hammers and it has saved my bacon more than once on hammers that aren't supposed to have hardener but needed something more in certain areas such as the killer octave.  This resin builds up the shoulders, i.e., power, quickly and the noise is easily voiced out with crown needling (with the Hart Voicing Tool of course!).  If a little more "bite" is needed, the tone will come right back up with a light sanding.  The beauty of these two resins is not in the tone or power they create, it's in the convenience and preparation time - a matter of minutes.

    All of these resins have a drying time and a curing time.  It can take months for the resin to give up the last little bit of solvent before we know the final tone. MEK is the fastest.   Alcohol will take the longest to give the final result.  Lacquer thinner is probably the most practical since MEK is not available in some states.
    I have found that in new hammer installations the PVC in MEK is the quickest and most stable.  It will be interesting to see if this catches on or fizzles out.  Hopefully this information is of some use. If so, remember you heard it here first. If not, I'll be the guy walking around the conventions with a bag on his head!   Happy Voicing - Glen

    ------------------------------
    Glen Hart
    Grand Junction CO
    970-434-5558
    ------------------------------



  • 25.  RE: Paraloid B72 as hammer hardner

    Posted 02-12-2019 23:18
    Very entertaining, educational, enjoyable read. Thank you Glenn for sharing. I happen to have 5 gallons of Mek just sitting there not knowing what to do with it.  Never would have thought about mixing that with pvc cement. Cool!





  • 26.  RE: Paraloid B72 as hammer hardner

    Posted 02-13-2019 15:13
    Glen-
    Interesting information.
    I suggest one refinement: although 70% isopropyl alcohol is the most common dilution, it can be found in drug stores in 99% and 50% dilutions as well.
    The 99% isopropyl seems to work quite well with paraloid B-72.
    I have found isopropyl the least offensive smelling solvent and especially prefer it for use in homes.

    ------------------------------
    Ed Sutton
    ed440@me.com
    (980) 254-7413
    ------------------------------



  • 27.  RE: Paraloid B72 as hammer hardner

    Posted 02-13-2019 21:05
    Thanks for making that clear.  That's what I was trying to convey when I wrote: " isopropyl is not necessarily rubbing alcohol". Any "relatively anhydrous" alcohol works well.  Usually rubbing alcohol has some oil and sometimes fragrance in it and lots of water.   The only reason I seldom use it is because MEK is so much faster in showing results.  Most of my work is in the shop so the smell is not a problem.

    ------------------------------
    Glen Hart
    Grand Junction CO
    970-434-5558
    ------------------------------



  • 28.  RE: Paraloid B72 as hammer hardner

    Posted 02-13-2019 22:24
    This is great information.

    I used to think that MEK was carcinogenic, but evidently it is not. Causes brain damage if exposure is too high but it won't give you cancer. Thats good. I also have a can of it and never knew what to do with it. Time to start experimenting...

    Thx Glen.

    Pwg

    ------------------------------
    Peter Grey
    Stratham NH
    603-686-2395
    pianodoctor57@gmail.com
    ------------------------------



  • 29.  RE: Paraloid B72 as hammer hardner

    Posted 02-13-2019 22:38
    Hi,

    Only FWIW, I've used MEK for limited, specific purposes for decades.
    For our purposes, MEK requires similar care to that required for Toulol,
    and pretty much anything that provides similar functions.

    Like everything else that we use as tools, we have to educate ourselves
    about our tools; especially ones that are chemically active. For me,
    this includes looking up the MSDS sheets from time to time to see if
    anything has changed since the last time I looked. Many times, it's all
    the same. Sometimes, it isn't. In any event, what's important is to be
    reasonable and careful in our use of substances for which there aren't
    necessarily any equally efficient and effective ways in which to do our
    work.

    I agree, Peter...time to start experimenting.

    Kind regards.

    Horace

    On 2/13/2019 7:24 PM, Peter Grey via Piano Technicians Guild wrote:
    > Please do not forward this message due to Auto Login.
    >
    > This is great information.
    >
    > I used to think that MEK was carcinogenic, but evidently it is not. Causes brain damage if exposure is too high but it won't give you cancer. Thats good. I also have a can of it and never knew what to do with it. Time to start experimenting...
    >
    > Thx Glen.
    >
    > Pwg
    >
    > ------------------------------
    > Peter Grey
    > Stratham NH
    > 603-686-2395
    > pianodoctor57@gmail.com
    > ------------------------------
    > -------------------------------------------
    > Original Message:
    > Sent: 02-13-2019 21:04
    > From: Glen Hart
    > Subject: Paraloid B72 as hammer hardner
    >
    > Thanks for making that clear.  That's what I was trying to convey when I wrote: " isopropyl is not necessarily rubbing alcohol". Any "relatively anhydrous" alcohol works well.  Usually rubbing alcohol has some oil and sometimes fragrance in it and lots of water.   The only reason I seldom use it is because MEK is so much faster in showing results.  Most of my work is in the shop so the smell is not a problem.
    >
    > ------------------------------
    > Glen Hart
    > Grand Junction CO
    > 970-434-5558
    > ------------------------------
    >
    > Original Message:
    > Sent: 02-13-2019 15:13
    > From: Ed Sutton
    > Subject: Paraloid B72 as hammer hardner
    >
    > Glen-
    > Interesting information.
    > I suggest one refinement: although 70% isopropyl alcohol is the most common dilution, it can be found in drug stores in 99% and 50% dilutions as well.
    > The 99% isopropyl seems to work quite well with paraloid B-72.
    > I have found isopropyl the least offensive smelling solvent and especially prefer it for use in homes.
    >
    > ------------------------------
    > Ed Sutton
    > ed440@me.com <ed440@me.com>
    > (980) 254-7413
    >
    > Original Message:
    > Sent: 02-12-2019 23:05
    > From: Glen Hart
    > Subject: Paraloid B72 as hammer hardner
    >
    > Hello All-  I'm late to the party as usual.  Unfortunately, my reading habits are such that I don't read this blog regularly.  My experiences with acrylic resin may be useful to some of you.  I was first introduced to Paraloid B72 (then called Acryloid) in 1978 in a paleontology class.  We used it for consolidating fossils by  applying it with paint brushes.  B72 was purchased in pre-mixed liquid resin form. There was also a powdered version that dissolved quickly.  However, I don't think it was B72 resin.  There are dozens of Paraloid resins with varying properties. There's also a line of "A" resins.   Much info on B72 can be gleaned from paleontology and museum conservation web sites.  I never thought much about Paraloid resins until 1989 when I was re-introduced to it while learning gold leafing in New York City in the Metropolitan Museum of Art.  It is used in the art world to consolidate decomposing gesso (among countless other uses). I restored a 1903 gold leafed Steinway B
    > that was on the cover of the PTJ in 2001.  The piano had a few areas of gesso under the gold that were strengthened with B72.
    >
    > Up until the 1990's I used nitrocellulose (NC) lacquer and occasionally shellac for voicing hammers. I once spent a day learning "lacquer voicing secrets" from Raymond Parada, one on one, in his office in the Steinway factory. He was "The Man" for a long time. They weren't really secrets, just the tried and true methods.  NC lacquer voicing is a perfectly legit method of voicing so don't believe all the bad press.  Also, the definition of a quality hammer is not based on the presence or absence of hardeners.
    >
    > In the early 90's I began experimenting with B72 for voicing but had a limited supply. This was before the days of the internet.  Because of price, availability, the preparation hassle and inconvenience of Paraloid B72,  I just quit using it when it ran out.  It's great that it is now readily available to us. The results were excellent and I preferred it over NC lacquer.  I had a limited amount of experience using it for voicing.  Probably only 4 or 5 sets of hammers.   There are lots of sources for acrylic resin. I have a dedicated spray room in my shop and have always used Sherwin-Williams products for refinishing, mainly because of availability.  I found that their "Moisture Resistant Lacquer" was a good source for a Paraloid B?? acrylic resin for voicing. The problem with lacquers has always been in knowing the "percent solids". This is eliminated with B72 as it is 100%.
    >
    > The entire purpose of all this rambling is to present a new protocol for juicing up hammers.  For at least twenty years I have been using two types of resin for voicing and have proven them over and over.  I've never heard of this before but I'm sure that somebody, somewhere has to have had the same idea. There are a lot of smart technicians in the PTG with thousands of years of experience.
    >
    > The first is an acrylic syrup.  I dissolve it in MEK or acetone.  In MEK it's ready to go in less than 5 minutes and in acetone about 10-15 minutes. It is used just like Paraloid B72 or acrylic or NC lacquer, or keytop or hammer hardener from supply houses.  It also cheap and readily available. This is just acrylic cement; aka: good ol' sniffin glue.  Don't worry, it's no more dangerous than any of the other voicing solutions. It can be purchased locally and has a long shelf life.  It can be mixed by weight or volume.  For every gram of resin I'll mix 5-10-15 or whatever grams of solvent, or drops or eyedroppers or tablespoons.  I've never been too worried about exact ratios.  I just think of the solutions as weak, medium, or strong.  This isn't rocket surgery.  It is always amusing when people agonize over whether to use a 1:8 or a 1:9 solution. The type of alcohol is not important. Methyl is the hottest, then ethyl, then propyl.  A can of hardware store denatured alcohol is all
    > you need in the shop. It is mostly ethanol, denatured with methanol. If you need something hotter, such as for French polishing shellac, then you can buy straight methanol. Otherwise, a few seconds difference in flash time isn't going to matter. (The flat areas of the gold piano were French polished with methanol.)  Just stay away from rubbing alcohol as it contains 30% water.  BTW- isopropyl alcohol is not necessarily rubbing alcohol.   Water will affect the resin and you definitely don't want to be pouring water onto felt that you're trying to harden.  Water doesn't dilute alcohol; alcohol dilutes water.
    >
    > The brand of acrylic glue I buy is Weld-On #16 for Acrylic Sheet.  I'm sure there are other brands that will work just as well. Acrylic syrups vary from approximately 70% to 90% resin, so get the the good stuff.  From my observations over the years it seems to be slightly harder than B72.  I have no data or done any testing so I'm just throwing this out there for whatever it's worth.  Also, I've never used the granules from the supply houses and the last time I used keytop was thirty years ago.  BTW, we occasionally hear of "collodion" used as a voicing solution in Europe. I've never used it. (What is sold today as a cosmetic is not the same stuff.) It has developed a sort of romantic aura about it, possibly because it is banned in the U.S. or that we imagine that it would give us that perfect elusive, magical tone if we could only get our hands on it.  It is nothing more than nitrocellulose resin dissolved in ether and alcohol.  It's probably one of the more dangerous concoctions
    > in the shop.
    >
    > The second voicing resin is my favorite and I use it almost exclusively.  It is pure vinyl resin -PVC.   This is sold as clear PVC cement that is used for connecting white PVC rigid pipe for plumbing and irrigation. It uses MEK as a solvent which stinks to high heaven.  It can be thinned with acetone or alcohol for less smell.  It also comes in a low VOC version which I have not tried.  It is great for the wholesale soaking of new sets of hammers and it has saved my bacon more than once on hammers that aren't supposed to have hardener but needed something more in certain areas such as the killer octave.  This resin builds up the shoulders, i.e., power, quickly and the noise is easily voiced out with crown needling (with the Hart Voicing Tool of course!).  If a little more "bite" is needed, the tone will come right back up with a light sanding.  The beauty of these two resins is not in the tone or power they create, it's in the convenience and preparation time - a matter of minutes.
    >
    > All of these resins have a drying time and a curing time.  It can take months for the resin to give up the last little bit of solvent before we know the final tone. MEK is the fastest.   Alcohol will take the longest to give the final result.  Lacquer thinner is probably the most practical since MEK is not available in some states.
    > I have found that in new hammer installations the PVC in MEK is the quickest and most stable.  It will be interesting to see if this catches on or fizzles out.  Hopefully this information is of some use. If so, remember you heard it here first. If not, I'll be the guy walking around the conventions with a bag on his head!   Happy Voicing - Glen
    >
    > ------------------------------
    > Glen Hart
    > Grand Junction CO
    > 970-434-5558
    >
    > Original Message:
    > Sent: 01-31-2019 18:07
    > From: Peter Grey
    > Subject: Paraloid B72 as hammer hardner
    >
    > Since alcohol is hygroscopic, I wonder if the addition of water to the mix helps mitigate the hardening action slightly.
    >
    > Pwg
    >
    > ------------------------------
    > Peter Grey
    > Stratham NH
    > 603-686-2395
    > pianodoctor57@gmail.com <pianodoctor57@gmail.com>
    >
    > Original Message:
    > Sent: 01-31-2019 11:25
    > From: John Musselwhite
    > Subject: Paraloid B72 as hammer hardner
    >
    > I bought mine from a Canadian conservation supplier as it seems Dale doesn't ship it to Canada (as I recall). I used the instructions here : (click to see the site from Bentside Arts)
    >
    > Rather than using acetone I prefer a "rectified spirit" like Everclear and use a transfer pipette to apply it as per the instructions. So far I've been quite pleased with the results.
    >
    > I made up full-strength and half-strength and keep it in the tiny plastic liquor bottles like you get on airplanes. I carry Protek and Profelt in similar bottles but have a different shaped bottle for each liquid. All bottles are labelled with a Brother Label Maker so I know what's actually in them!
    >
    >
    >
    > ------------------------------
    > John Musselwhite, RPT
    > Calgary, AB Canada
    > www.musselwhite.com
    >
    > Original Message:
    > Sent: 01-30-2019 17:45
    > From: Dave Conte
    > Subject: Paraloid B72 as hammer hardner
    >
    > I have purchased and want to try using Paraloid B72 as a hammer hardener.
    > The package says 95% acetone mixture for consolidating or reinforcing
    > plaster like materials.
    >
    > What does anyone using this for hammers use as a proportion for hammer
    > hardener?
    >
    > ------------------------------
    > Dave Conte
    > Owner
    > North Richland Hills TX
    > 817-581-7321
    > ------------------------------
    >
    >
    > Reply to Sender : https://my.ptg.org/eGroups/PostReply/?GroupId=43&SenderKey=9e630203-91a1-491d-8c04-f5c286672e79&MID=699075&MDATE=756%253e457468&UserKey=3feecf45-4a69-4cff-bbb2-fd6c7eaf0569&sKey=KeyRemoved
    >
    > Reply to Discussion : https://my.ptg.org/eGroups/PostReply/?GroupId=43&MID=699075&MDATE=756%253e457468&UserKey=3feecf45-4a69-4cff-bbb2-fd6c7eaf0569&sKey=KeyRemoved
    >
    >
    >
    > You are subscribed to "Pianotech" as hgreeley@sonic.net. To change your subscriptions, go to http://my.ptg.org/preferences?section=Subscriptions&MDATE=756%253e457468&UserKey=3feecf45-4a69-4cff-bbb2-fd6c7eaf0569&sKey=KeyRemoved. To unsubscribe from this community discussion, go to http://my.ptg.org/HigherLogic/eGroups/Unsubscribe.aspx?UserKey=3feecf45-4a69-4cff-bbb2-fd6c7eaf0569&sKey=KeyRemoved&GroupKey=2bb4ebe8-4dba-4640-ae67-111903beaddf.
    >




  • 30.  RE: Paraloid B72 as hammer hardner

    Posted 02-13-2019 22:51
    Glen,
    Thanks for sharing your experiences and experiments. It seems pretty clear that there are many substances that can work quite well for stiffening hammer felt. There's another acrylic formulation that would probably work well: cyano-acrylic. CA thinned in acetone. I haven't tried it (I haven't had that much occasion for doping hammers in recent years, beyond surface application for more attack zing), but it has certainly crossed my mind.

    That said, I think that it is probably more useful to explore the details of where and how the substances are used. We presumably want hammers to have a particular gradient of flexibility and stiffness in different parts of the structure. How is that best achieved?

    I have been interested in comparing hammers today with those of the early and mid 19th century, before the industrialization of hammer making, when hammer covering was a skilled manual craft. There were many experiments with shapes and materials, but the general rule was many thin layers, with the stiffest (almost always leather) next to the molding, and progressively softer, more resilient layers toward the outside.

    With the advent of the single sheet pressed with tons of pressure around a full set of moldings, we have a very different animal. Lots of things have been written about how to needle and how to apply hardener, some of it quite contradictory, some of it quite consistent. I have tried to take the more consistent ideas, and meld them with history, and the most basic core principle seems to be similar to 19th century: stiff/dense core, resilient/softer shoulders, and a crown layer that is softened, but quite subtlely and with the need to maintain that condition through work.

    Both needling and application of hardener can use these guidelines for where and how to use them.

    ------------------------------
    Fred Sturm
    University of New Mexico
    fssturm@unm.edu
    http://fredsturm.net
    http://www.artoftuning.com
    "We either make ourselves happy or miserable. The amount of work is the same." - Carlos Casteneda
    ------------------------------



  • 31.  RE: Paraloid B72 as hammer hardner

    Posted 02-14-2019 17:12
    Fred-
    In response to your second paragraph: that is the $64,000 question.  In my IMAGINARY voicing world I have created my own model that helps me cope with not knowing what is really happening.  Everything I do, every needle poke in any direction or depth, and every drop of whatever solution is to affect how the center circle/cylinder deforms, holds then releases energy.( I hope the pics and video came thru)  This is entirely conceptual since the cylinder doesn't actually exist in the hammer.  I'm a big believer in the "iron fist in a velvet glove" idea and the Steinway shape hammer. I like a nice cushion on the top of the hammer.   I especially imagine the side circles when I side needle or put solution on the sides.
    I don't want energy going way down the sides much past the top of the molding.  I have videos showing that the felt of some hammers can deform down to about the staple area but in my IMAGINARY world I want to keep that energy higher up in areas where I can work with it.   I have used CA glue and thinned epoxy to harden the felt in a pattern similar to the gray reinforced area of older hammers. I like to think it worked well but sometimes I wonder and it is a real PITA.  I do, however, always saturate that area with a strong solution of acrylic resin from Weld-O #16 .
    The circle/cylinder is the perfect shape to express the non-linear stiffness coeffecient.  How the two side circles deform is just as important.  If one side of the hammer is harder that the other then the circle/cylinder will deform asymetrically and the release of power will not be straight into the string.  The black & white photo shows the asymmetrical  deformation of a hammer that is either over or under centering.  In this case the cylinder shifts to the side and is no longer in line with top of the molding.This will result in diminished energy/power transferred into the string.​ An asymmetrical shaped hammer  will be impossible to voice. This is probably all academic since  the strings are rarely parallel to the keybed anyway.   In practice I can't be worrying about it when I'm boring hammers.  We all have to have a model we want to achieve.    I suppose I should come up with a name for my model but the good ones have already been taken.  The "sacred drop" is my favorite.  I'll just call it "Hart's imaginary voicing world" for now.   As you know, there's a lot more to this and is should probably be in a different thread as I've digressed from the original.  So here's my question: How do you guys find time to write?  This is killin" me!

    ------------------------------
    Glen Hart
    Grand Junction CO
    970-434-5558
    ------------------------------



  • 32.  RE: Paraloid B72 as hammer hardner

    Posted 02-14-2019 19:12
    I just read my post so before anyone comments please don't misinterpret the last line and be offended.  I enjoy writing and sharing the information so that isn't what's killing me.   It's just finding the time to do things outside the work environment that doesn't involve a jeep in Colorado.  Apologies in advance,  Sincerely,  Glen

    ------------------------------
    Glen Hart
    Grand Junction CO
    970-434-5558
    ------------------------------



  • 33.  RE: Paraloid B72 as hammer hardner

    Posted 04-06-2019 22:29
    Hello all,

    One follow up question regarding Paraloid B-72. I'm preparing to use it for voicing up an under-lacquered Steinway at the end of next week. I plan to dissolve it in acetone, then apply appropriate strengths to the various parts of the hammers.

    My question is: what is the best tool to apply it? I have a polyurethane bottle needle dropper that I used for ProTek. Is that safe to use, or will it destroy the bottle and leak all over the piano? I also have a glass pipette, though I'm not as comfortable using it.

    Thanks in advance,

    ------------------------------
    Benjamin Sanchez
    Professional Piano Services
    (805)315-8050
    www.professional-piano-services.com
    ------------------------------



  • 34.  RE: Paraloid B72 as hammer hardner

    Posted 04-08-2019 11:06
    I've more experience doping with lacquer and I've always hated the stuff because of the fumes and the long drying time.   However,  there is one issue with the use of these plastic solutions which worries me, and that is the solvents used.   I'm sure you've all encountered at one time or another hammer felt which has popped off the molding due to failure of the glue holding it on.   Both alcohol and acetone can be quite effective at weakening a glue joint, a property which can sometimes be useful.  When I do a set of Yamaha hammer spring loops the application of acetone to the groove in the flange which holds the cord will allows me to pare off the old glue quite easily. And if you've ever encountered a bar piano where someone has spilled a cocktail inside the action,  you'll know alcohol can be quite effective at disassembling all the various glue joints to be found.  I've always assumed that lacquer thinner does not have the same effect, but I've not tried it with that view in mind so perhaps I'm wrong about that.  I'm not familiar with what glue is commonly used nowadays to press hammer felt these days--there is such a variety of adhesives available--but is there not some danger here in weakening this bond?

    ------------------------------
    Cecil Snyder
    Torrance CA
    310-542-7108
    ------------------------------



  • 35.  RE: Paraloid B72 as hammer hardner

    Posted 04-09-2019 08:44
    Mr. Sanchez,

    The Gaunt Hypo-oiler .049 sold by pianotek and others works very well for this purpose.

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