Pianotech

Another take on dead soundboard repair.  I don't usually deal with dead boards, but I just finished a job on a horribly constructed no-name 4-11 grand where I tried  to either prove or disprove a hunch I have been thinking about. Its based on my observation, of many dead boards, both old and new   

A board's structure is created by the glue interfaces. The glue interfaces,are to a large degree, the board's structure. The interfaces are between ribs and panel, panel and rim. When there is a failure of any glue joint in this system, even if the majority of components have life in them, when a joint in the system is compromised, the whole structure goes south. Specifically, when I see the amount of work that goes into reglueing ribs in the normal ways, I roll my eyes. The "restored" rib to panel joints I see folks spending so much time and effort working on, never regain the lost structure because the repaired glue joints are not actually, and almost certainly can't be, structurally sound glue joints. The problem with this, is that challenged glue joints at the panel/rib joint equals dead board (as well as other joint failures or degradations).

Panel cracks, by definition, have to create rib/panel glue-line degradation,because in order for the panel to crack, the shear amount of movement at the crack and surrounding area has to degrade or destroy the all important glue-line between rib an panel. The degradation can be catastrophic failure, as in clear separation of rib and panel, or it can be less obvious pulling of the very weak spruce surface grains somewhat loose, if not completely loose, allowing too much micro-movement in that all important rib to panel glue joint. 

Glue line failure or weakness at the rim, as well, will destroy a perfect board with 100 percent excellent panel/rib structure. I've seen it on new boards.

I also am not convinced as the the value that the stiffness of the panel itself provides, as a panel, with no ribs, have almost no structure across the grain at all. Any belly installer has experienced how, without the ribs, one can easily destroy a soundboard panel, as its so wimpy. 
 
So, my hunch was, that while not expecting 100 percent (or even close to that) rejuvenation, how far could fixing the rib/panel joints, in a way that produced a real new adequate glue joint get this previously dead board? 

So, we took this dead board and played with it. It was for sure dead...even though someone had previously shimmed the usual way, and attempted to re-glue ribs, the usual way. Using a multi tool with a 90 deg bend in the cutter, we excavated a 1/4" kerf to new wood all along the entire length of each rib (except high treble which was not accessible), both sides of the rib, at the rib/panel glue joint. Then filled the kerf with west system 105 resin and colloidal silica, adding a small fillet to the filled kerf. That's all we did...no epoxy to the panel. We inspected the rim joints to make sure we thought they were reasonable  (not a 100 percent provable thing), and then did bridge cap work, which is real important, biggest bang for the buck work.

Results?  Its not one of my new boards for sure, but the improvement is musically significant. Sounds better than marginally acceptable, certainly way better than before. Sustain not as good as a new board, but not absent, as it was previously. Bass still too flexible, but some mass loading helped that out a bit. Mid-Treble is okay with the classic alto capo 4th-5th octaves weaknesses present, ie some too close impedance matches. high 5th octave and up, quite nice, with nice sustain, I'd expect in a good new board.

Would I do it again...probably not, as I prefer the sustain and texture differentiation my new boards get, and its a lot of work for patch up some else's not very good design. But experimenting with a decent glue-joint restoration at the rib/panel joint provided some interesting observations.





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

Jim-
As always, you have a way of taking a fresh look at old ideas.
I've seen European rebuilds with lines of screws through the soundboard into the ribs.
Would this serve a purpose similar to what you did?

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

Original Message:
Sent: 11-24-2019 21:00
From: Jim Ialeggio
Subject: A slightly different way of looking at dead board soundboard work

Another take on dead soundboard repair.  I don't usually deal with dead boards, but I just finished a job on a horribly constructed no-name 4-11 grand where I tried  to either prove or disprove a hunch I have been thinking about. Its based on my observation, of many dead boards, both old and new

A board's structure is created by the glue interfaces. The glue interfaces,are to a large degree, the board's structure. The interfaces are between ribs and panel, panel and rim. When there is a failure of any glue joint in this system, even if the majority of components have life in them, when a joint in the system is compromised, the whole structure goes south. Specifically, when I see the amount of work that goes into reglueing ribs in the normal ways, I roll my eyes. The "restored" rib to panel joints I see folks spending so much time and effort working on, never regain the lost structure because the repaired glue joints are not actually, and almost certainly can't be, structurally sound glue joints. The problem with this, is that challenged glue joints at the panel/rib joint equals dead board (as well as other joint failures or degradations).

Panel cracks, by definition, have to create rib/panel glue-line degradation,because in order for the panel to crack, the shear amount of movement at the crack and surrounding area has to degrade or destroy the all important glue-line between rib an panel. The degradation can be catastrophic failure, as in clear separation of rib and panel, or it can be less obvious pulling of the very weak spruce surface grains somewhat loose, if not completely loose, allowing too much micro-movement in that all important rib to panel glue joint.

Glue line failure or weakness at the rim, as well, will destroy a perfect board with 100 percent excellent panel/rib structure. I've seen it on new boards.

I also am not convinced as the the value that the stiffness of the panel itself provides, as a panel, with no ribs, have almost no structure across the grain at all. Any belly installer has experienced how, without the ribs, one can easily destroy a soundboard panel, as its so wimpy.

So, my hunch was, that while not expecting 100 percent (or even close to that) rejuvenation, how far could fixing the rib/panel joints, in a way that produced a real new adequate glue joint get this previously dead board?

So, we took this dead board and played with it. It was for sure dead...even though someone had previously shimmed the usual way, and attempted to re-glue ribs, the usual way. Using a multi tool with a 90 deg bend in the cutter, we excavated a 1/4" kerf to new wood all along the entire length of each rib (except high treble which was not accessible), both sides of the rib, at the rib/panel glue joint. Then filled the kerf with west system 105 resin and colloidal silica, adding a small fillet to the filled kerf. That's all we did...no epoxy to the panel. We inspected the rim joints to make sure we thought they were reasonable  (not a 100 percent provable thing), and then did bridge cap work, which is real important, biggest bang for the buck work.

Results?  Its not one of my new boards for sure, but the improvement is musically significant. Sounds better than marginally acceptable, certainly way better than before. Sustain not as good as a new board, but not absent, as it was previously. Bass still too flexible, but some mass loading helped that out a bit. Mid-Treble is okay with the classic alto capo 4th-5th octaves weaknesses present, ie some too close impedance matches. high 5th octave and up, quite nice, with nice sustain, I'd expect in a good new board.

Would I do it again...probably not, as I prefer the sustain and texture differentiation my new boards get, and its a lot of work for patch up some else's not very good design. But experimenting with a decent glue-joint restoration at the rib/panel joint provided some interesting observations.





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

In my opinion, emphatically no...it makes no sense at all to me. for these reasons:

1- a screw connection is not a glue joint connection. Assuming a good screw seat, which is difficult to achieve where access is so challenging, in soft woods, the linear movement it allows will be limited to restrictions only at point loads. Said another way, the actual square inches of connection is miniscule, compared to a good glue joint. Then there is the mushy-ness of the spruce to relative to the steel at those very limited point loads.  

2-screwing, ie, making holes in the beam (rib) all along its length, is taking one of the only members of the structure, which does not degrade too much, and actively reducing the structural effectiveness of the rib.

3-imagine it this way...would you ever dream of the attachment of rib to panel, in a new board to be solely a forest of screws?

4-the shear tonnage of steel added to the board, in a structure which is already marginal, is greatly altering, and I would say damping whatever sustain the structure might have had.



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

Original Message:
Sent: 11-25-2019 11:21
From: Ed Sutton
Subject: A slightly different way of looking at dead board soundboard work

Jim-
As always, you have a way of taking a fresh look at old ideas.
I've seen European rebuilds with lines of screws through the soundboard into the ribs.
Would this serve a purpose similar to what you did?

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

Original Message:
Sent: 11-24-2019 21:00
From: Jim Ialeggio
Subject: A slightly different way of looking at dead board soundboard work

Another take on dead soundboard repair.  I don't usually deal with dead boards, but I just finished a job on a horribly constructed no-name 4-11 grand where I tried  to either prove or disprove a hunch I have been thinking about. Its based on my observation, of many dead boards, both old and new

A board's structure is created by the glue interfaces. The glue interfaces,are to a large degree, the board's structure. The interfaces are between ribs and panel, panel and rim. When there is a failure of any glue joint in this system, even if the majority of components have life in them, when a joint in the system is compromised, the whole structure goes south. Specifically, when I see the amount of work that goes into reglueing ribs in the normal ways, I roll my eyes. The "restored" rib to panel joints I see folks spending so much time and effort working on, never regain the lost structure because the repaired glue joints are not actually, and almost certainly can't be, structurally sound glue joints. The problem with this, is that challenged glue joints at the panel/rib joint equals dead board (as well as other joint failures or degradations).

Panel cracks, by definition, have to create rib/panel glue-line degradation,because in order for the panel to crack, the shear amount of movement at the crack and surrounding area has to degrade or destroy the all important glue-line between rib an panel. The degradation can be catastrophic failure, as in clear separation of rib and panel, or it can be less obvious pulling of the very weak spruce surface grains somewhat loose, if not completely loose, allowing too much micro-movement in that all important rib to panel glue joint.

Glue line failure or weakness at the rim, as well, will destroy a perfect board with 100 percent excellent panel/rib structure. I've seen it on new boards.

I also am not convinced as the the value that the stiffness of the panel itself provides, as a panel, with no ribs, have almost no structure across the grain at all. Any belly installer has experienced how, without the ribs, one can easily destroy a soundboard panel, as its so wimpy.

So, my hunch was, that while not expecting 100 percent (or even close to that) rejuvenation, how far could fixing the rib/panel joints, in a way that produced a real new adequate glue joint get this previously dead board?

So, we took this dead board and played with it. It was for sure dead...even though someone had previously shimmed the usual way, and attempted to re-glue ribs, the usual way. Using a multi tool with a 90 deg bend in the cutter, we excavated a 1/4" kerf to new wood all along the entire length of each rib (except high treble which was not accessible), both sides of the rib, at the rib/panel glue joint. Then filled the kerf with west system 105 resin and colloidal silica, adding a small fillet to the filled kerf. That's all we did...no epoxy to the panel. We inspected the rim joints to make sure we thought they were reasonable  (not a 100 percent provable thing), and then did bridge cap work, which is real important, biggest bang for the buck work.

Results?  Its not one of my new boards for sure, but the improvement is musically significant. Sounds better than marginally acceptable, certainly way better than before. Sustain not as good as a new board, but not absent, as it was previously. Bass still too flexible, but some mass loading helped that out a bit. Mid-Treble is okay with the classic alto capo 4th-5th octaves weaknesses present, ie some too close impedance matches. high 5th octave and up, quite nice, with nice sustain, I'd expect in a good new board.

Would I do it again...probably not, as I prefer the sustain and texture differentiation my new boards get, and its a lot of work for patch up some else's not very good design. But experimenting with a decent glue-joint restoration at the rib/panel joint provided some interesting observations.





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

I am assuming you mean a kerf, the width of the thickness of the blade, extending 1/4 inch in along the top of the rib where it interfaces with the board.

------------------------------
Floyd Gadd
Regina SK
306-502-9103
------------------------------

Original Message:
Sent: 11-24-2019 21:00
From: Jim Ialeggio
Subject: A slightly different way of looking at dead board soundboard work

Another take on dead soundboard repair.  I don't usually deal with dead boards, but I just finished a job on a horribly constructed no-name 4-11 grand where I tried  to either prove or disprove a hunch I have been thinking about. Its based on my observation, of many dead boards, both old and new

A board's structure is created by the glue interfaces. The glue interfaces,are to a large degree, the board's structure. The interfaces are between ribs and panel, panel and rim. When there is a failure of any glue joint in this system, even if the majority of components have life in them, when a joint in the system is compromised, the whole structure goes south. Specifically, when I see the amount of work that goes into reglueing ribs in the normal ways, I roll my eyes. The "restored" rib to panel joints I see folks spending so much time and effort working on, never regain the lost structure because the repaired glue joints are not actually, and almost certainly can't be, structurally sound glue joints. The problem with this, is that challenged glue joints at the panel/rib joint equals dead board (as well as other joint failures or degradations).

Panel cracks, by definition, have to create rib/panel glue-line degradation,because in order for the panel to crack, the shear amount of movement at the crack and surrounding area has to degrade or destroy the all important glue-line between rib an panel. The degradation can be catastrophic failure, as in clear separation of rib and panel, or it can be less obvious pulling of the very weak spruce surface grains somewhat loose, if not completely loose, allowing too much micro-movement in that all important rib to panel glue joint.

Glue line failure or weakness at the rim, as well, will destroy a perfect board with 100 percent excellent panel/rib structure. I've seen it on new boards.

I also am not convinced as the the value that the stiffness of the panel itself provides, as a panel, with no ribs, have almost no structure across the grain at all. Any belly installer has experienced how, without the ribs, one can easily destroy a soundboard panel, as its so wimpy.

So, my hunch was, that while not expecting 100 percent (or even close to that) rejuvenation, how far could fixing the rib/panel joints, in a way that produced a real new adequate glue joint get this previously dead board?

So, we took this dead board and played with it. It was for sure dead...even though someone had previously shimmed the usual way, and attempted to re-glue ribs, the usual way. Using a multi tool with a 90 deg bend in the cutter, we excavated a 1/4" kerf to new wood all along the entire length of each rib (except high treble which was not accessible), both sides of the rib, at the rib/panel glue joint. Then filled the kerf with west system 105 resin and colloidal silica, adding a small fillet to the filled kerf. That's all we did...no epoxy to the panel. We inspected the rim joints to make sure we thought they were reasonable  (not a 100 percent provable thing), and then did bridge cap work, which is real important, biggest bang for the buck work.

Results?  Its not one of my new boards for sure, but the improvement is musically significant. Sounds better than marginally acceptable, certainly way better than before. Sustain not as good as a new board, but not absent, as it was previously. Bass still too flexible, but some mass loading helped that out a bit. Mid-Treble is okay with the classic alto capo 4th-5th octaves weaknesses present, ie some too close impedance matches. high 5th octave and up, quite nice, with nice sustain, I'd expect in a good new board.

Would I do it again...probably not, as I prefer the sustain and texture differentiation my new boards get, and its a lot of work for patch up some else's not very good design. But experimenting with a decent glue-joint restoration at the rib/panel joint provided some interesting observations.





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

yes...the multitool blade will end up removing about 2 mm of wood total in the thickness of the kerf (blade width +tooth offset+amount the tool is wiggled around as you work in such a tight space) . As the point of the exercise is creating an adequate glue joint, yes the kerf is located in the original glue joint between rib and panel.

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

Original Message:
Sent: 11-25-2019 13:32
From: Floyd Gadd
Subject: A slightly different way of looking at dead board soundboard work

I am assuming you mean a kerf, the width of the thickness of the blade, extending 1/4 inch in along the top of the rib where it interfaces with the board.

------------------------------
Floyd Gadd
Regina SK
306-502-9103

Original Message:
Sent: 11-24-2019 21:00
From: Jim Ialeggio
Subject: A slightly different way of looking at dead board soundboard work

Another take on dead soundboard repair.  I don't usually deal with dead boards, but I just finished a job on a horribly constructed no-name 4-11 grand where I tried  to either prove or disprove a hunch I have been thinking about. Its based on my observation, of many dead boards, both old and new

A board's structure is created by the glue interfaces. The glue interfaces,are to a large degree, the board's structure. The interfaces are between ribs and panel, panel and rim. When there is a failure of any glue joint in this system, even if the majority of components have life in them, when a joint in the system is compromised, the whole structure goes south. Specifically, when I see the amount of work that goes into reglueing ribs in the normal ways, I roll my eyes. The "restored" rib to panel joints I see folks spending so much time and effort working on, never regain the lost structure because the repaired glue joints are not actually, and almost certainly can't be, structurally sound glue joints. The problem with this, is that challenged glue joints at the panel/rib joint equals dead board (as well as other joint failures or degradations).

Panel cracks, by definition, have to create rib/panel glue-line degradation,because in order for the panel to crack, the shear amount of movement at the crack and surrounding area has to degrade or destroy the all important glue-line between rib an panel. The degradation can be catastrophic failure, as in clear separation of rib and panel, or it can be less obvious pulling of the very weak spruce surface grains somewhat loose, if not completely loose, allowing too much micro-movement in that all important rib to panel glue joint.

Glue line failure or weakness at the rim, as well, will destroy a perfect board with 100 percent excellent panel/rib structure. I've seen it on new boards.

I also am not convinced as the the value that the stiffness of the panel itself provides, as a panel, with no ribs, have almost no structure across the grain at all. Any belly installer has experienced how, without the ribs, one can easily destroy a soundboard panel, as its so wimpy.

So, my hunch was, that while not expecting 100 percent (or even close to that) rejuvenation, how far could fixing the rib/panel joints, in a way that produced a real new adequate glue joint get this previously dead board?

So, we took this dead board and played with it. It was for sure dead...even though someone had previously shimmed the usual way, and attempted to re-glue ribs, the usual way. Using a multi tool with a 90 deg bend in the cutter, we excavated a 1/4" kerf to new wood all along the entire length of each rib (except high treble which was not accessible), both sides of the rib, at the rib/panel glue joint. Then filled the kerf with west system 105 resin and colloidal silica, adding a small fillet to the filled kerf. That's all we did...no epoxy to the panel. We inspected the rim joints to make sure we thought they were reasonable  (not a 100 percent provable thing), and then did bridge cap work, which is real important, biggest bang for the buck work.

Results?  Its not one of my new boards for sure, but the improvement is musically significant. Sounds better than marginally acceptable, certainly way better than before. Sustain not as good as a new board, but not absent, as it was previously. Bass still too flexible, but some mass loading helped that out a bit. Mid-Treble is okay with the classic alto capo 4th-5th octaves weaknesses present, ie some too close impedance matches. high 5th octave and up, quite nice, with nice sustain, I'd expect in a good new board.

Would I do it again...probably not, as I prefer the sustain and texture differentiation my new boards get, and its a lot of work for patch up some else's not very good design. But experimenting with a decent glue-joint restoration at the rib/panel joint provided some interesting observations.





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

Experiments are fun though. And i'm sure you learned something from it. My concern on this procedure would be the time factor, so it will probably stay in the experimental department. You hit upon a key element though, and that is weight.  The screw procedure  mentioned would add about a pound and a half to the board.  I'm sure also that the epoxy would also add weight.  Weight is an important element to consider. Most of my own experiments have focused on reducing weight. usually my soundboards are about 6 pounds lighter than the original. I am currently reading a book written in 1768.  It is about the mechanics(physics) of keyboard instruments. The author states:

"You will observe that new harpsichords (as is the case with most musical instruments) do not sound
as agreeable and brilliant as those that have been played a while. The main reason for
this is that the wood keeps getting dryer and lighter".
He later talks about the importance of ribbing and their locations. It surprises me how much they actually knew back then and how most of that knowledge has been lost, fortunately some have also been found.  

Since you mentioned a 4'10" Grand, I too am working on a 4'10" Behning. Also poorly designed. My first observation of the soundboard was its extreme weight  of 15lbs. How can a little board weigh so much? 

An experiment I am cooking up right now shows some promise. Using compression across the grain to create further tension  along the grain.  But what do I know, i'm just a grey avatar.

------------------------------
If it's pinging, it's not singing, it's just ringing,
chernobieffpiano.com
grandpianoman@protonmail.com
Knoxville, TN
865-986-7720
------------------------------

Original Message:
Sent: 11-25-2019 14:43
From: Jim Ialeggio
Subject: A slightly different way of looking at dead board soundboard work

yes...the multitool blade will end up removing about 2 mm of wood total in the thickness of the kerf (blade width +tooth offset+amount the tool is wiggled around as you work in such a tight space) . As the point of the exercise is creating an adequate glue joint, yes the kerf is located in the original glue joint between rib and panel.

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

Original Message:
Sent: 11-25-2019 13:32
From: Floyd Gadd
Subject: A slightly different way of looking at dead board soundboard work

I am assuming you mean a kerf, the width of the thickness of the blade, extending 1/4 inch in along the top of the rib where it interfaces with the board.

------------------------------
Floyd Gadd
Regina SK
306-502-9103

Original Message:
Sent: 11-24-2019 21:00
From: Jim Ialeggio
Subject: A slightly different way of looking at dead board soundboard work

Another take on dead soundboard repair.  I don't usually deal with dead boards, but I just finished a job on a horribly constructed no-name 4-11 grand where I tried  to either prove or disprove a hunch I have been thinking about. Its based on my observation, of many dead boards, both old and new

A board's structure is created by the glue interfaces. The glue interfaces,are to a large degree, the board's structure. The interfaces are between ribs and panel, panel and rim. When there is a failure of any glue joint in this system, even if the majority of components have life in them, when a joint in the system is compromised, the whole structure goes south. Specifically, when I see the amount of work that goes into reglueing ribs in the normal ways, I roll my eyes. The "restored" rib to panel joints I see folks spending so much time and effort working on, never regain the lost structure because the repaired glue joints are not actually, and almost certainly can't be, structurally sound glue joints. The problem with this, is that challenged glue joints at the panel/rib joint equals dead board (as well as other joint failures or degradations).

Panel cracks, by definition, have to create rib/panel glue-line degradation,because in order for the panel to crack, the shear amount of movement at the crack and surrounding area has to degrade or destroy the all important glue-line between rib an panel. The degradation can be catastrophic failure, as in clear separation of rib and panel, or it can be less obvious pulling of the very weak spruce surface grains somewhat loose, if not completely loose, allowing too much micro-movement in that all important rib to panel glue joint.

Glue line failure or weakness at the rim, as well, will destroy a perfect board with 100 percent excellent panel/rib structure. I've seen it on new boards.

I also am not convinced as the the value that the stiffness of the panel itself provides, as a panel, with no ribs, have almost no structure across the grain at all. Any belly installer has experienced how, without the ribs, one can easily destroy a soundboard panel, as its so wimpy.

So, my hunch was, that while not expecting 100 percent (or even close to that) rejuvenation, how far could fixing the rib/panel joints, in a way that produced a real new adequate glue joint get this previously dead board?

So, we took this dead board and played with it. It was for sure dead...even though someone had previously shimmed the usual way, and attempted to re-glue ribs, the usual way. Using a multi tool with a 90 deg bend in the cutter, we excavated a 1/4" kerf to new wood all along the entire length of each rib (except high treble which was not accessible), both sides of the rib, at the rib/panel glue joint. Then filled the kerf with west system 105 resin and colloidal silica, adding a small fillet to the filled kerf. That's all we did...no epoxy to the panel. We inspected the rim joints to make sure we thought they were reasonable  (not a 100 percent provable thing), and then did bridge cap work, which is real important, biggest bang for the buck work.

Results?  Its not one of my new boards for sure, but the improvement is musically significant. Sounds better than marginally acceptable, certainly way better than before. Sustain not as good as a new board, but not absent, as it was previously. Bass still too flexible, but some mass loading helped that out a bit. Mid-Treble is okay with the classic alto capo 4th-5th octaves weaknesses present, ie some too close impedance matches. high 5th octave and up, quite nice, with nice sustain, I'd expect in a good new board.

Would I do it again...probably not, as I prefer the sustain and texture differentiation my new boards get, and its a lot of work for patch up some else's not very good design. But experimenting with a decent glue-joint restoration at the rib/panel joint provided some interesting observations.





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

Here's what I learned...some of it unexpected...

1-Confirmed my hunch about the importance of a continuous rib long unbroken glue joint...but that's really pretty "duh"...but still to see it play out in real time and hear the results informs my usual work, because I can hear the weaknesses that are still extant, and hear how far we were able to get with that one parameter.
 
2-Unexpected...but actually, not really so, as I literately have been seeing this in my own boards...The treble is really quite nice, 6th octave up to 88, nice sustain you'd expect in a good well designed belly. Since I was not able to get up into the treble case recesses to re-glue the ribs up in this area, and since the board was shimmed pretty well up there, this area was well beat, and not possessing astounding levels of stiffness. The success of the treble suggests hyper stiffness is just not needed in this area, which is quite contrary to what my mentor taught me. I'm not sure what Ron was smoking in terms of excessive stiffness. Though possessing some level of stiffness, the board still needs to be able to move, and move in a fashion that assists transverse string motion. Restricting it with aggressive grain angles to the belly rail, building it hyper stiff, and applying ribs in non-parallel fashion, especially in the short rib area, kills the board's ability to encourage transverse string movement. Not only does hyper stiffness and purposely designed restriction not necessary for good treble tone, but it actively chokes it. I have been wanting to see what the threshold of adequate treble stiffness is...but frankly, if something this beat can function very well, I'm wondering where the heck that threshold actually is...I don't think I've hit it yet.

That said the terminations, bridge work,  capo shaping, co-polymer counterbearing terminations (I did not make this an FTDS treble), hammer weight and shaping, and tight shank pinning, all play highly determinant roles up there, and I think their execution is the primary high treble parameter to get right. I did all these thing to this piano. But I think the board can chill somewhat in the stiffness department up there...just say'in.  

Mid treble is a different story, rather than 6th octave and up I referred to above. The mid treble was..acceptable to somewhat ehhh. Not Steinway old board explosive, but able to function well at lower amplitudes, but breaks up way too early. 

Client, whose grandfather won this thing in a poker game, is thrilled...he really wanted to keep in the family.  But it was really horribly built, and we ended up making all kinds of new parts especially in the fore-finishing department...serious hash fabrication.

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

Original Message:
Sent: 11-25-2019 20:36
From: Chris Chernobieff
Subject: A slightly different way of looking at dead board soundboard work

Experiments are fun though. And i'm sure you learned something from it. My concern on this procedure would be the time factor, so it will probably stay in the experimental department. You hit upon a key element though, and that is weight.  The screw procedure  mentioned would add about a pound and a half to the board.  I'm sure also that the epoxy would also add weight.  Weight is an important element to consider. Most of my own experiments have focused on reducing weight. usually my soundboards are about 6 pounds lighter than the original. I am currently reading a book written in 1768.  It is about the mechanics(physics) of keyboard instruments. The author states:

"You will observe that new harpsichords (as is the case with most musical instruments) do not sound
as agreeable and brilliant as those that have been played a while. The main reason for
this is that the wood keeps getting dryer and lighter".
He later talks about the importance of ribbing and their locations. It surprises me how much they actually knew back then and how most of that knowledge has been lost, fortunately some have also been found.

Since you mentioned a 4'10" Grand, I too am working on a 4'10" Behning. Also poorly designed. My first observation of the soundboard was its extreme weight  of 15lbs. How can a little board weigh so much?

An experiment I am cooking up right now shows some promise. Using compression across the grain to create further tension  along the grain.  But what do I know, i'm just a grey avatar.

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If it's pinging, it's not singing, it's just ringing,
chernobieffpiano.com
grandpianoman@protonmail.com
Knoxville, TN
865-986-7720

Original Message:
Sent: 11-25-2019 14:43
From: Jim Ialeggio
Subject: A slightly different way of looking at dead board soundboard work

yes...the multitool blade will end up removing about 2 mm of wood total in the thickness of the kerf (blade width +tooth offset+amount the tool is wiggled around as you work in such a tight space) . As the point of the exercise is creating an adequate glue joint, yes the kerf is located in the original glue joint between rib and panel.

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

Original Message:
Sent: 11-25-2019 13:32
From: Floyd Gadd
Subject: A slightly different way of looking at dead board soundboard work

I am assuming you mean a kerf, the width of the thickness of the blade, extending 1/4 inch in along the top of the rib where it interfaces with the board.

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Floyd Gadd
Regina SK
306-502-9103

Original Message:
Sent: 11-24-2019 21:00
From: Jim Ialeggio
Subject: A slightly different way of looking at dead board soundboard work

Another take on dead soundboard repair.  I don't usually deal with dead boards, but I just finished a job on a horribly constructed no-name 4-11 grand where I tried  to either prove or disprove a hunch I have been thinking about. Its based on my observation, of many dead boards, both old and new

A board's structure is created by the glue interfaces. The glue interfaces,are to a large degree, the board's structure. The interfaces are between ribs and panel, panel and rim. When there is a failure of any glue joint in this system, even if the majority of components have life in them, when a joint in the system is compromised, the whole structure goes south. Specifically, when I see the amount of work that goes into reglueing ribs in the normal ways, I roll my eyes. The "restored" rib to panel joints I see folks spending so much time and effort working on, never regain the lost structure because the repaired glue joints are not actually, and almost certainly can't be, structurally sound glue joints. The problem with this, is that challenged glue joints at the panel/rib joint equals dead board (as well as other joint failures or degradations).

Panel cracks, by definition, have to create rib/panel glue-line degradation,because in order for the panel to crack, the shear amount of movement at the crack and surrounding area has to degrade or destroy the all important glue-line between rib an panel. The degradation can be catastrophic failure, as in clear separation of rib and panel, or it can be less obvious pulling of the very weak spruce surface grains somewhat loose, if not completely loose, allowing too much micro-movement in that all important rib to panel glue joint.

Glue line failure or weakness at the rim, as well, will destroy a perfect board with 100 percent excellent panel/rib structure. I've seen it on new boards.

I also am not convinced as the the value that the stiffness of the panel itself provides, as a panel, with no ribs, have almost no structure across the grain at all. Any belly installer has experienced how, without the ribs, one can easily destroy a soundboard panel, as its so wimpy.

So, my hunch was, that while not expecting 100 percent (or even close to that) rejuvenation, how far could fixing the rib/panel joints, in a way that produced a real new adequate glue joint get this previously dead board?

So, we took this dead board and played with it. It was for sure dead...even though someone had previously shimmed the usual way, and attempted to re-glue ribs, the usual way. Using a multi tool with a 90 deg bend in the cutter, we excavated a 1/4" kerf to new wood all along the entire length of each rib (except high treble which was not accessible), both sides of the rib, at the rib/panel glue joint. Then filled the kerf with west system 105 resin and colloidal silica, adding a small fillet to the filled kerf. That's all we did...no epoxy to the panel. We inspected the rim joints to make sure we thought they were reasonable  (not a 100 percent provable thing), and then did bridge cap work, which is real important, biggest bang for the buck work.

Results?  Its not one of my new boards for sure, but the improvement is musically significant. Sounds better than marginally acceptable, certainly way better than before. Sustain not as good as a new board, but not absent, as it was previously. Bass still too flexible, but some mass loading helped that out a bit. Mid-Treble is okay with the classic alto capo 4th-5th octaves weaknesses present, ie some too close impedance matches. high 5th octave and up, quite nice, with nice sustain, I'd expect in a good new board.

Would I do it again...probably not, as I prefer the sustain and texture differentiation my new boards get, and its a lot of work for patch up some else's not very good design. But experimenting with a decent glue-joint restoration at the rib/panel joint provided some interesting observations.





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