If you want a repair that doesn't show any screws then the method is to drill two holes into the rib on either side of the soundboard crack. Usually these separations occur in conjunction with a crack but if not then determine at what interval you will need screws depending on the length the rib separation. Tyically every 1.5 - 2 " is enough. Before you drill, insert a thin feeler gauge in the gap so that the drill stops short of the soundboard panel. The diameter of the hole should be larger than the screw shank so the screw can be inserted without binding on the sides of the hole. I usually use a 7/32" drill, which allows me to use a 7/32" hammer shank dowl, and a screw whose shank diameter, then, is slightly less. Work some wood glue into the joint (feeler gauges are good for that too) and then using a self tapping wood screw, insert the screw into the hole and screw it into the panel to pull the panel to the rib. Usually I use thick cardboard punchings (front rail) to protect the rib, and adjust for the thickness of the rib versus the length of the screw, and maybe a washer against the punchings so that the rib is not marred. Choose the number punchings so that the screw just barely but not noticeably pops through the top of the soundboard panel. A small pinpoint is all you should see.
When the glue is dry, leave it overnight, then remove the screw and using the same 7/32" drill bit with a drill stop, drill up into the soundboard panel so that it can receive a dowel but don't punch through the top of the board. When dry, trim the dowel flush and you can stain and but a drop of shellac on the end of the dowel to make it look a bit less obvious.
Now you have a repair which is only apparent from the bottom side of the piano and shows only as the ends of a dowel. From the topside it will be invisible.
Original Message:
Sent: 12-28-2023 07:58
From: Peter Grey
Subject: Loose Ribs
My first choice would be to use nice looking brass screws from the top side (no bigger than #8) where ever access is reasonably good, including through the strings (its simply inconvenient but can be done). I would also opt for an aliphatic type glue such as Titebond 3 (longer working time). I would save the CA for the very final micro areas where I could not get normal adhesive.
Where access is otherwise impossibly limited I would have to get creative. I have done this numerous times successfully.
What is the problem with putting screws? If the client simply says no, then tell them the strings and plate need to come out and a rebuild is in order. Then you can use go bars and wedges. It's not your fault this happened. You need to protect your own reputation. If the client is handcuffing you, walk away. If you're handcuffing yourself, that's a different story altogether.
Peter Grey Piano Doctor
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Peter Grey
Stratham NH
(603) 686-2395
pianodoctor57@gmail.com
Original Message:
Sent: 12-28-2023 01:02
From: David Love
Subject: Loose Ribs
I would be surprised if an airbag would give you enough pressure unless you're using something like a soundboard press fire hose type clamp.
Not sure why you don't want to use screws unless the ribs are not accessible because of the bracing. You don't have to go all the way through the board, You can just drill a hole through the rib but not into the panel, sink a screw up into the soundboard panel to pull the panel back to the rib and plug it with a dowel later, hardly noticeable.
Or I agree with using wooden wedges though it might be easier to flip the piano over to do that. I would not use CA glue for this repair.
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David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320
Original Message:
Sent: 12-27-2023 22:02
From: Peter Grey
Subject: Loose Ribs
Philip,
That is what I had in mind...above and below. Good old wedges also work from down below too.
Peter Grey Piano Doctor
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Peter Grey
Stratham NH
(603) 686-2395
pianodoctor57@gmail.com
Original Message:
Sent: 12-27-2023 14:53
From: Philip Jamison
Subject: Loose Ribs
The air bag is a good idea. Wonder is they might work used both above and below the board.
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Philip Jamison
West Chester PA
(610) 696-8449
Original Message:
Sent: 12-27-2023 13:18
From: Peter Grey
Subject: Loose Ribs
Philip,
That will only work if you can support it against something solid on the top side. Otherwise it's a recipe for disaster if it sets before you can hold it in place long enough.
I would suggest using inflatable bags (like "Winbag" or similar) to do your pressurizing between the strings or plate on the top, and beams underneath. Squeeze tight first, then apply CA. Don't use your fingers, DAMHIK.
Edit: There is no harm in putting modest screws through from the top where you can get to it. Several European makers do this all over the place (or at least used to).
Peter Grey Piano Doctor
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Peter Grey
Stratham NH
(603) 686-2395
pianodoctor57@gmail.com
Original Message:
Sent: 12-27-2023 11:33
From: Philip Jamison
Subject: Loose Ribs
Thanks for that idea, Wim. The piano is on its side now.
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Philip Jamison
West Chester PA
(610) 696-8449
Original Message:
Sent: 12-27-2023 11:27
From: Wim Blees
Subject: Loose Ribs
Since you don't want to do any drilling, I would suggest you try to squirt some medium CA glue in the gap, and then while applying pressure with your fingers, or with a screw driver, to push the rib up to the board, and squirt it with the kicker.
If there is a chance to do so, it might be easier to put the piano on its side.
Wim
Original Message:
Sent: 12/27/2023 11:20:00 AM
From: Philip Jamison
Subject: RE: Loose Ribs
The ribs appear to be not very well glued to the board, and are loose in spots. The soundboard does not appear to be warped or distorted.
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Philip Jamison
West Chester PA
(610) 696-8449
Original Message:
Sent: 12-27-2023 10:47
From: Wim Blees
Subject: Loose Ribs
Phil
Has the rib come off the soundboard, or did the soundboard come off the rib? There is a difference. Do you need to push the rib up to the soundboard, or pull the soundboard down to the rib?
Wim
Original Message:
Sent: 12/27/2023 10:40:00 AM
From: Philip Jamison
Subject: Loose Ribs
I have a Kawai grand in the shop with loose ribs. There are no soundboard cracks; just several ribs partially unglued in spots. The "repair" was clarinet reeds jammed between ribs and board. Any ideas on re-gluing without drilling holes? It would be easier if the strings were out, but I'd like to avoid that. The piano was previously in a music studio and never abused.
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Philip Jamison
West Chester PA
(610) 696-8449
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