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Old cello restoration

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This is regarding that Klotz like cello again. Ken Su in San Mateo , Ca. will be doing the restoration. The cello has a large piece of fabric like material glued along the inside of the bottom rib. This was the method used when "repairing" the cracks seen in the picture. Ken said the fabric has to be removed to do the job correctly using wood cleets instead. Another luthier said he would apply hot water to soften it off. This scared me because what will constant exposure to water do to the already fragile wood. Ken said he will carefully carve it off. My question is this: I've worked on many pieces of antique furniture. On some of these restorations I've had to strip off old paint to expose the wood underneath. I've done this with that commercial stuff used to remove varnish etc. Do you think I could apply some of this stuff sparingly until these "skins" swell off. It wouldn't be on there long. That gooey acid stuff doesnt take long to get the job done.

post-28921-1242098888_thumb.jpg

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Ken Su in San Mateo , Ca. will be doing the restoration.

. Do you think I could apply some of this stuff sparingly until these "skins" swell off. It wouldn't be on there long. That gooey acid stuff doesnt take long to get the job done.

Um.

I thought Ken Su was doing the restoration. :) Why would you apply anything?

This is one of the more difficult jobs, fixing shattered and distorted cello ribs.

If I were you, I would just back away and let a professional you trust do the work.

But hey, it's your cello. :)

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Um.

I thought Ken Su was doing the restoration. :) Why would you apply anything?

This is one of the more difficult jobs, fixing shattered and distorted cello ribs.

If I were you, I would just back away and let a professional you trust do the work.

But hey, it's your cello. :)

Thanks for your post. Ken is old school and hes charging by the hour. He said to me this one area is the most difficult and would take longer to repair. He suggested originally, that we replace the whole bottom rib and keep the original for later replacement. That would mean more money. I trust him whole heartedly. I know the stuff works but hes never used it. I put this out there to see if any of you have had any experience with the stuff. I think it will work.

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An old chair and old cello are completely different things. “Gooey acid stuff,” isn’t anything that I’d want to have near an old instrument. I’ll take water and patience over chemicals and ruin any day.

I agree with the earlier post. The best thing to do is stop thinking, and simply let the man do his job. I’m certain that your repairer is using his best judgment, and has much more experience.

The problem with recommending a nontraditional approach to something you've never done is... well... self explanatory.

The cello related threads seem to be dominating the forum, please be considerate.

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An old chair and old cello are completely different things. “Gooey acid stuff,” isn’t anything that I’d want to have near an old instrument. I’ll take water and patience over chemicals and ruin any day.

I agree with the earlier post. The best thing to do is stop thinking, and simply let the man do his job. I’m certain that your repairer is using his best judgment, and has much more experience.

The problem with recommending a nontraditional approach to something you've never done is... well... self explanatory.

The cello related threads seem to be dominating the forum, please be considerate.

Thanks Iburkard, I don't uderstand the comment at the end of your post. "Please be considerate" Forums are just that, forums. I consider the folks in Maestronet pretty savy. I appreciate their imput. But they respond and comment if they like. My posting or anyone else doing same doesn't prevent others from participating if they desire to. I'd say just ignor a post, question or whatever like the vast majority does. I think this is what you are referring to when you say "please be considerate".

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strippers such as bix, jasco and alike will not act on hide glue well...

regarding water, applying warm damp rags to soften the glue would be the least invasive way to remove the burlap mesh...

to repair that rib, from what i see, a good deal of water will need to be used in order to get those split and curled areas playable enough to be re-flattened anyway...i don't see that as a dry bending operation

careful scraping would work too, but would take 5 times longer...and does risk further damaging the already damaged wood,becasue well that seems quite structurally compromised to begin with...again the key is careful, which = time, think prison break with a rat tail file...

it could be fixed, but boy its pretty wasted...

related to the violin being different than a piece of furniture...pa'lease we all know that a violin is not a piece of furniture or a house or anything else built from wood, however they are all wood and all science related to construction,repair apply, there is no magic about it...just proven construction,repair techniques,blueprints, tricks and knowledge of adhesives,fasteners and finishes within what ever the project parameter is...

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strippers such as bix, jasco and alike will not act on hide glue well...

regarding water, applying warm damp rags to soften the glue would be the least invasive way to remove the burlap mesh...

to repair that rib, from what i see, a good deal of water will need to be used in order to get those split and curled areas playable enough to be re-flattened anyway...i don't see that as a dry bending operation

careful scraping would work too, but would take 5 times longer...and does risk further damaging the already damaged wood,becasue well that seems quite structurally compromised to begin with...again the key is careful, which = time, think prison break with a rat tail file...

it could be fixed, but boy its pretty wasted...

related to the violin being different than a piece of furniture...pa'lease we all know that a violin is not a piece of furniture or a house or anything else built from wood, however they are all wood and all science related to construction,repair apply, there is no magic about it...just proven construction,repair techniques,blueprints, tricks and knowledge of adhesives,fasteners and finishes within what ever the project parameter is...

Thanks Jezzup, I totally agree with you that wood is wood. Working carefully and patiently while taking into account the medium is key. The warm wet rags to remove the mesh was the first luthier's suggestion. He did mention the need to make the rib soft and plyable to repair correctly. It all seems to fall into place now. Now I know where he was coming from.

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I too would avoid "gooey acidy stuff". A little water and time will do just fine. You should probably just let your repairman do his job and not interfere.

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I too would avoid "gooey acidy stuff". A little water and time will do just fine. You should probably just let your repairman do his job and not interfere.

++++++++++++

If this is my cello or my violin, I would just let the repairman to do the job. Why?

Removing the old varnish is the last thing I should be concerned with.

Once the varnish remover (chemical) gets into the wood, I don't know how to get it out.

It would make the damaged wood worst than before. In my opinion it looks bad, and it sounds bad.

if you treat the wood with some sort of chemical on your instrument. So avoid using chemical except

hide glue, clamps. Replace old clothes (burlap ?) . No point to repair old clothes. Patience is virtue.

I would take a vacation.

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related to the violin being different than a piece of furniture...pa'lease we all know that a violin is not a piece of furniture or a house or anything else built from wood...

Juzzupe... the poster brought up the notion of furniture repair, and how this experience might apply here. While the experience does help with finishing and a few other basic things, the care required is so much greater. I wasn't being creatively snide.

I'd say just ignore a post, question or whatever like the vast majority does. I think this is what you are referring to when you say "please be considerate".

Your enthusiasm about your instrument is entirely understandable and appreciated. I had the same excitement with my first violin (well... every one).

I’ve been following all of your cello threads for a month or more, eagerly awaiting the repaired images. You need to understand that it’s a little frustrating for MNs to see the same instrument and images posted again and again under different headings with no real progress on any level, and new fundamental curiosity questions. Again, it’s fun to talk about a potential approach to a repair, but in this case our advice is kind of throwaway, because the work is already being done. Also, what if your repairer is part of this forum?

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You need to understand that it’s a little frustrating for MNs to see the same instrument and images posted again and again under different headings....

It hasn't frustrated or bothered me.

I would find it very interesting if you could post a series of pictures showing the restoration process.

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My approach, which I've had to do on old basses and cellos before, would be to slightly wet the fabric surface then lay a piece of paper towel on and then wet the paper towel and keep it slightly wet, it will liquify the old glue while minimizing the amount of water needed and let the damp work over time, check often and peel away the fabic when you are able, scrub with an old tooth brush and warm water to clean the rest of the old glue off the wood. system works well on the rib to plate areas with build up of old/bad glue.

forming the wood rib back to its old shape involves heat, moisture and time, sometimes the old cracks will not close and will need to be filled to avoid introducing unneeded tension. I like to use large sections of veneer formed to the inside to bridge large areas of cracks and weak buckled areas (rather than multulpe cleats) the surface area is stronger. on inexpensive instruments I would use a three layer ply material I found in hobby stores - very flexiable , very strong and 1/2mm thick, I can cold form it while being glued to the curve shape. the cross grain plys mean good strength in keeping the crack closed, very stable and strong, flexible to move with the rib and much less weight added to the rib.

Reese

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I still find the fact that I see this cello every week with no progress a little annoying. I'm allowed. :) Also, I thought we batted around this topic before (the complexity of the repair) in an older thread. The only new variable is a cloth patch. I could ignore the thread, but returned with interest which has been somewhat deflated... no new images.

I agree that wetting will probably be necessary to fix the amount of concavity on the rib wood between cracks. I'm really interested in seeing how cleanly the cracks are repaired. I just worked on a violin with a crushed bottom block, and was surprised at how well the whole rib mess resolved - one small line out of six or seven cracks.

Would it be best to create an outside form and push the warping damage flat, or apply a backing on the inside and pull the damage in? For me, the goal would be stability, without adding much new material.

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iburk'

oh i was'nt thinking that...

but trust me, there are situations with restoration and conservation that i've been involved with, with furniture that are very similar to this repair...

i guess from a wood workers perspective i just really dislike this overly romantic magical pixie dust foo,foo fantasy world revolving the building of glorified boxes that make sound...

not implying you were implying such...

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I still find the fact that I see this cello every week with no progress a little annoying. I'm allowed. :) Also, I thought we batted around this topic before (the complexity of the repair) in an older thread. The only new variable is a cloth patch. I could ignore the thread, but returned with interest which has been somewhat deflated... no new images.

I agree that wetting will probably be necessary to fix the amount of concavity on the rib wood between cracks. I'm really interested in seeing how cleanly the cracks are repaired. I just worked on a violin with a crushed bottom block, and was surprised at how well the whole rib mess resolved - one small line out of six or seven cracks.

Would it be best to create an outside form and push the warping damage flat, or apply a backing on the inside and pull the damage in? For me, the goal would be stability, without adding much new material.

+++++++++++

Now, you are talking.

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.... Ken is old school and hes charging by the hour. .... He suggested originally, that we replace the whole bottom rib and keep the original for later replacement. ...

I'll admit I haven't kept up with the other threads on this particular cello, but looking at the photo in the first post, and reading this comment, I am wondering why this route was discarded. What can be seen of the ribs is not good, and that it's been repaired before for what appears to be the same problem means that more repair may not hold for long either. Are you planning to play this instrument, or restore it for display? I know we try to save as much of the original wood as possible, but with wood cleats or veneer, you are adding mass to these ribs that wasn't originally present anyway -- you may be preserving the exterior, but not the intent of the instrument, which was to make music.

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I'll admit I haven't kept up with the other threads on this particular cello, but looking at the photo in the first post, and reading this comment, I am wondering why this route was discarded. What can be seen of the ribs is not good, and that it's been repaired before for what appears to be the same problem means that more repair may not hold for long either. Are you planning to play this instrument, or restore it for display? I know we try to save as much of the original wood as possible, but with wood cleats or veneer, you are adding mass to these ribs that wasn't originally present anyway -- you may be preserving the exterior, but not the intent of the instrument, which was to make music.

Thanks Ken I agree with your assessment. It is my intention to bring this cello back to playing condition. I'd like to do that while trying to maintain its original character. We'll see if it can be accomplished

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Once the rib is removed from the bottom block and the corner blocks have been split, and the old glue is removed using a moist paper towel and time, a form should be made of the outside of the rib for pressing. Clean and possibly bleach the cracks. Cover the form with a couple layers of aluminum flashing, this flashing keeps the rib from picking up the grain of the form. An inside counter form that is shorter than the outside form is then made and lined with closed cell rubber, about 1/2 " thick. Add moisture via a wet piece of wet brown paper on the inside and press--leave for 1 month. When the the rib is dry, coax the cracks back together using strips of natural drum head soaked in glue. Apply the drum head spanning the cracks on the inside, and place back in the form and let dry for about 2 weeks. Repeat. Repeat, etc. until the cracks are closed. Once the cracks are closed , remove half the thickness of the rib in the affected area. Mack a new double rib to adhere to the inside that is half the thickness of the final rib. Glue doubling in place, let dry, cut down doubling to final thickness, and reglue split blocks and rib to block. Touchup.---All in all it is a tricky job, not appropriate for the untrained hand.

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Hi Jerry. For as much as I understood the procedure is like the one described by H. Weisshaar in his book (surely a task for a pro).

....... coax the cracks back together using strips of natural drum head soaked in glue......

For "Natural Drum Head" you mean something like "pergamena" paper (goat skin) or something else?

Albert

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Once the rib is removed from the bottom block and the corner blocks have been split, and the old glue is removed using a moist paper towel and time, a form should be made of the outside of the rib for pressing. Clean and possibly bleach the cracks. Cover the form with a couple layers of aluminum flashing, this flashing keeps the rib from picking up the grain of the form. An inside counter form that is shorter than the outside form is then made and lined with closed cell rubber, about 1/2 " thick. Add moisture via a wet piece of wet brown paper on the inside and press--leave for 1 month. When the the rib is dry, coax the cracks back together using strips of natural drum head soaked in glue. Apply the drum head spanning the cracks on the inside, and place back in the form and let dry for about 2 weeks. Repeat. Repeat, etc. until the cracks are closed. Once the cracks are closed , remove half the thickness of the rib in the affected area. Mack a new double rib to adhere to the inside that is half the thickness of the final rib. Glue doubling in place, let dry, cut down doubling to final thickness, and reglue split blocks and rib to block. Touchup.---All in all it is a tricky job, not appropriate for the untrained hand.

Hello and thanks for this information. Is this something you would do. I would rather have this job done than just another "band aid" type repair. Would you be interested in doing this job if so, what might I expect to pay. I'd have the current repair person remove the rib and I'd sent it to you if this is possible

Thanks Harry

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I just finished taking a workshop on rib repair and block replacement. Jerry has the correct method. The fabric on the ribs is a well known method of reinforcement. Stradivari used fabric to reinforce ribs. You can't just remove the rib and send it to someone, because the rib will change shape when off the instrument. The wooden counterform has to be made from the instrument itself. This is not a job for an unskilled person! I haven't done this on a cello, so I'm just guessing, but I would expect to pay a couple thousand $ to have that rib repaired.

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