Work done on the Rybka mandola

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I'll start this with this link for context.
https://www.mandolincafe.com/forum/s...ighlight=rybka

The owner of this mandola thought it would be of interest to the "mandolin community" to post some info and photos of the maintenance/repairs work done. I've recently finished this work, so here goes.
I'll post here during short sessions over the next few days. I have over 100 photos ready for internet use, so I don't really want to invest the time all at once.

These photos will not always be in the order they were taken, so if you see work that has been done but not yet discussed, that is the reason. The chronology of the work and the chronology of the description of the work do not always match up.

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First, some of the things I found that needed attention, then we'll get into other observations and the work done.
I started by removing the pick guard, basically just to get it out of the way, and out of harms way, during the work. It came off relatively easily. many of you know how hard it can be to remove some of the old Gibson mandolin pick guards, and we can consider ourselves lucky when it is easy!

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The fingerboard was loose from the neck for about half of it's length, and the extender was completely loose from the top.

(That tool is simply a thin palette knife, I use them to find and evaluate loose glue joints, and to show them in pictures)

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There were a few loose places in the back-to-rim glue joint. The back was removed from this mandola at some time, almost certainly by Gibson, and a Virzi was installed. Apparently the glue joint was not perfect when it went back together, and so places (such as this one) came loose over time.

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I'll come back later.
I've had this happen before; when I try to post a lot of images at once, the process starts to fail and the images don't show. Perhaps later it will work and I can continue

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I'll get ahead of myself a little here.
The fingerboard popped right off, as I suspected considering how much of the glue joint had already failed.

I wasn't so lucky with the extender. It was still securely glued to the 'board, though it had come completely looks from the top. I had to use heat and moisture to get it to com off.

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The mother of pearl nut was sitting in a shallow slot in the neck. That would later turn out to be an advantage. (we'll get to that...)

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The neck has a center strip, and the glue joint was starting to fail here.

With the 'board removed, I was able to find that the f glue joint holding the truss rod filler stick was failing too.

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The ivoroid plastic binding binding was coming loose in several places, mostly resulting from the plastic shrinking and pulling loose in the curves.

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The lower body point protector apparently went missing at some time, and someone replaces it with a piece of wood.


- - - Updated - - -

That is most of what I found in need of work. I'll get to the work done when I come back.

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Alignment was suffering where the back was loose from the rim near the tail block, so I made this pair of clamping cauls t use to align the glue joint.

They are made from wood with a very soft surface, and they are made to fit very well so no padding is needed. With these cauls I was able to use a bar clamp to force the rim into position for re-gluing the open joint.

The red color in the picture is from my heat lamp that I used to warm the joint in order to have a little more working time with hide glue.

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With the rim aligned with the back, I was able to glue and clamp the open joint.

It turned out looking good.

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Alignment was not great here either, but with the large head block and corner block glued to the inside of the rim there was nothing I could do to improve it, so I simply glued and clamped the joint.

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When plastic bindings shrink and pull loose at the curves of an instrument body, then cannot normally be successfully re-glued because they must be stretched back into position. There are two main options here: 1. heat and stretch the bindings until they will comfortably fit back in place, then glue them, or 2. cut the binding so that a piece can be added to restore the length in order for the binding to once again fit in place.
Loose bindings bindings can catch on things and and pulled to make the situation much worse. Wood can pull loose from the instrument, finish can be flaked and damaged, so in m opinion repairing the bindings is important to the long-term health of the instrument.
I discussed the situation with the owner, informed him of the risk of finish damage from heating and stretching the bindings, and before I was even through explaining, he chose method 2; piece in small bits of binding to restore the fit where needed.
with the bindings cut, they were easy to glue back into place using binding tape and glue.

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Withe the bindings secured in place once again, I filled the little gaps with matching binding material. This mandola has a black binding layer to the inside of an ivoroid layer. In one place the black binding had pulled loose, but in the other places the ivoroid had separated from the black.

I used a pipette and very small drops of acetone to "glue" the binding pieces in. Acetone can damage the finish, so I had to keep it exactly where it belonged, wicking into the joints, without getting on the finish surface.

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After those pieces cured I cut them down to the level of the bindings and later touched up the color and finish. We'll get to that later.

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Turning the nut on the truss rod could change the alignment of the loose joint of the filler stick in the neck. I adjusted it for best alignment, warmed the neck, and with a clean finger pressed, rubbed and massaged hot hide glue into the open joint. That's why there is so much glue in the surface. When clamping pressure was applied, glue squeezed up out of the joint assuring me that the joint was well glued and closed.

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The open joint at the back of the neck was a somewhat different story. Clamping the sides of the neck (as shown above) opened the joint rather than closing it, so I needed a method of concentrating clamping pressure at the back of the neck shaft.

These leather-padded cauls were my solution. i was able to close and glue the open joint at the back of the neck in a similar manner as above.


Due to the various pieces of the neck being of different woods that shrink and swell differently, alignment at the back of the neck was off enough that one can feel the edges of the center strip. It is not objectionable, in my opinion, and will improve with playing wear. Sometimes we just have to accept things like that in old instruments.

[Ken]

Thanks John,
Great to see the pictures of the work being done.

[Timbofood]

Thanks John! I really enjoy watching these projects.

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A couple of thing here.
There are two visible tight top cracks near the fingerboard extender. I forced as much hot hide glue into those as I could, and they should be stable for the foreseeable future.
The other thing is the lack of color around the edge of the extender. (The extender is in place here but not yet glued.) I don't know how long ago the glue joint failed and how long the extender was loose from the top, but it was long enough that some finish and color was lost. The extender also could have shrunk and left the uncolored bit of wood exposed around the edge.
I added some matching color. It is just a cosmetic thing, but it is the type of thing that makes glue joints look more like they haven't been tampered with. It is nice when repairs are difficult to detect.

I used a quill to apply the color (my old standby, Pelikan brand sepia drawing ink).

Here is the result.

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Here is the extender glued and clamped back in position.

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Some more cosmetic work, and a decision made in conjunction with the owner.
We decided to remove and replace the wooden point protector with one that looks like the other point.
It only took a little effort to dislodge the wooden point.

When it was removed completely, it left behind a reasonably clean original surface. Thankfully whoever put it there didn't glue it too securely.

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Corner points were dovetailed into the binding in those days. One piece of evidence that we look for when determining whether a back has been removed (for Virzi installation, or for other reasons) is the lack of a dovetailed end on the points where they intersect the back binding. The upper point shows this absence of a dovetailed end, and I could have installed my replacement point either way; dovetailed or not. We decided to replace the point without the dovetail in the back binding since it is evident that the back was removed from this mandola to install the Virzi.
Here's the upper point showing the dovetail at one end and not at the other.

I wondered about the originality of this point because it is ivoroid rather than bone. There is a little bit of color at the base of the material that was not scraped off, the scrape marks are continuous into the binding, and all in all, it looks like the upper point has been there all along. If it is not original, whoever replaced it did a great job of making it look like it has always been there, and either way, original or not, I decided to match it with my replacement lower point.

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I cut a piece of ivoroid, with the grain running across the piece, to use for the replacement point...

...fit the ends; one dovetailed, one straight...

...marked the shape...

...and cut it close to final shape.