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seam crack at end block - how big a repair?


Cedar
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AS I as sitting in rehearsal today waiting for the 20 measures of rest to end I glanced at my violin. When much to my dismay I notice a bulge in the rib right below the chin rest. I kept playing but right afterwards I examined the situation a little more carefully. There is definite separation between the top and the rib right below the chin rest.

My question is how major a repair is this? What concerns me is since the crack is down at bottom of the violin the rib has separated from the end block and the instrument is going to have to be popped open to make the repair.

I'll have the repair done whatever it takes but I'd like to know what I'm getting into before hand.

Thanks

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If I understand properly, the back is loose on the rib and block.........

Tops get a lot of reglueing. When a back comes loose it may be the original glue joint or something seldom fixed. (Most likely the former if the violin is under 100 years old.)

This is a reason to be optimistic. I would say to be wary of shops that want large amounts of money or exagerate the situation. Likely all that is needed is to unstring the violin and let it sit a day or two. Then a craftsman would wash out any excess glue with warm water and reglue. There is likely to be little of this if it is the original glue joint. Any warping is simply pushed back in place; perhaps the glue joint would be opened for a bit beyond the obvious opening that you now see. (Hell, maybe the whole back joint is flaky. Even if it is, the job is not a problem provided they do not decide to separate the back at the neck.

As explaination, consult Michael's accounting of his viola being made for Ethan. The back is glued on first.. This means that all excess glue can be washed away from the inside. Likely, if this is the original seam gone bad, there is little or no washing to be done. In my practice, however, I wet the area at least to give a homogeneous bond to the new glue.

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"I notice a bulge in the rib right below the chin rest."

There are two types of rib bulges common in the chinrest area: One is caused by the chinrest being tightened too much; the other is caused by the top and back shrinking narrower which makes the rib too long. Since you also say the rib has come unglued from the block, it sounds to me like you have the second type of bulge. Since the rib is now too long, the usual repair is to make it shorter by planing a little wood off its end at the end pin, and then regluing it to the block. I make this repair without removing the top, unless the top is coming off for some other reason. This is not a major repair.

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Thanks for the advice. My panic quotient has dropped substantially. The seam that is failing is an original, as the instrument is only 24 years old. This is the first time something like this has happened, so I am like a new father hearing baby's first cough.

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The first step is separating the rib from the block. This is the hardest part because there is danger of damaging the thin rib. The safest way to do it to to remove the top and chisel the block out in little pieces which requires fitting a new block after the rib has been shortened. With the top on, an opening knife can be inserted into the rib/block seam after removing the saddle. Cedar says his rib is unglued from the block, so the hardest part is already done on his violin.

Then open the seams between the rib and the top and back almost to the corner. The rib can now be flexed out enough to plane it shorter on the end. You want to take small cuts with a very sharp plane. The linings will probably need to be shortened, as well. I use a 6mm knife for this. Sometimes the linings are loose and need to be reglued to the rib. I made some special clamps for this. When the rib and linings have been shortened enough, the rib is reglued to the block using a clamp like "HERDIM End Pin Clamp, Violin, No. 735800" shown at http://www.dick.biz/, and the seams between the rib and the top and back are reglued.

I've also been able to shorten the upper ribs with the top on. This is only possible if the rib has come completely unglued from the block, because there is no access for the opening knife here the way there is at the lower block after the saddle is removed. There is no access, either, for the plane to shorten the rib, so I press the rib tightly against the neck foot and draw a pencil line on the rib against the neck foot. Then I flex the rib away from the neck and trim it to the pencil line with a knife or chisel. I repeat drawing the line and trimming to it until the rib is short enough, shorten and reglue the linings as necessary and glue everything back together.

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  • 15 years later...

I have a 1920s era American Violin with the rib unglued from the bottom end block. It appears the bottom end block is still glued to the top and back. However, the top is unglued from the rib about 3 inches on one side and about 1 inch on the other side. The bottom is also unglued from the rib, but only for 1/2 inch on one side and 1 inch on the other side.

My plan is to clamp and re-glue the rib to the bottom end block and to glue the back and top to the rib simultaneously. 

Prior to gluing, while attempting to clamp the rib to the bottom end block to re-glue it, I only tightened the clamp such that the space between the rib and the outer edge of the top and bottom are equal to the areas where the rib is still attached to the top and bottom, about 2mm. At that point there remains a gap of about 2mm between the rib and the bottom end block.

I suspect there was 2mm lining between the rib and the bottom end block which is missing.

This violin has no cracks or other damage, so I really don't want to take it apart.

Would crafting and gluing a 2mm lining between the rib and the bottom end block be an appropriate repair?

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21 hours ago, PNM said:

 

Prior to gluing, while attempting to clamp the rib to the bottom end block to re-glue it, I only tightened the clamp such that the space between the rib and the outer edge of the top and bottom are equal to the areas where the rib is still attached to the top and bottom, about 2mm. At that point there remains a gap of about 2mm between the rib and the bottom end block.

 

I'm confused........

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I'm confused, too.

 

22 hours ago, PNM said:

...I suspect there was 2mm lining between the rib and the bottom end block which is missing...

 

56 minutes ago, Wood Butcher said:

...linings are inside the ribs after all....

 

Yes, the linings are inside and you cannot see them, in the vicinity of the lower block, without a mirror and an interior light.  So I don't see how you would suspect a missing lining piece or know that the missing piece measures 2 millimeters.

You must mean something other than "lining."

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23 hours ago, PNM said:

I have a 1920s era American Violin with the rib unglued from the bottom end block. It appears the bottom end block is still glued to the top and back. However, the top is unglued from the rib about 3 inches on one side and about 1 inch on the other side. The bottom is also unglued from the rib, but only for 1/2 inch on one side and 1 inch on the other side.

My plan is to clamp and re-glue the rib to the bottom end block and to glue the back and top to the rib simultaneously. 

Prior to gluing, while attempting to clamp the rib to the bottom end block to re-glue it, I only tightened the clamp such that the space between the rib and the outer edge of the top and bottom are equal to the areas where the rib is still attached to the top and bottom, about 2mm. At that point there remains a gap of about 2mm between the rib and the bottom end block.

I suspect there was 2mm lining between the rib and the bottom end block which is missing.

This violin has no cracks or other damage, so I really don't want to take it apart.

Would crafting and gluing a 2mm lining between the rib and the bottom end block be an appropriate repair?

Pics are worth 100.000,,,,,,,,,,,,,,,,,,,,

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  • 2 weeks later...

You have been so polite!! As I re-read my post, I have no idea what I was talking about. I'll try harder in the future.

You are right! The rib has shrunk. I shaved a little off of one of the ribs and everything fit together swimmingly. I repaired the cracked rib and reinforced the repair with linen, sealed with shellac. I re-glued the back, top, block and ribs and everything is solid.

I do have a 2 mm peg hole alignment problem that is discussed in a new topic -  paraphrase - " moving the peg hold on an old fiddle".

Thanks for trying to help me, and have a nice day.

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