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How To Glue A Top Back?


Fellow
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Hi all,

It is not a simple procedure. I have seen a few tops glued back ( I do not know who have done the jobs) in such terrible fashions.

Over hangs (edge) are uneven. They probably did it free handed. I do not think that is the way (free hand) to do it.

What is your usual way? (I have to use pin holes)

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Pin holes? I never use pin holes.

+++++++++++

Here is the pin hole on the back. There are pin holes on the top too.

Some violins do not have pin holes. It makes the job much more interesting.

Like you have a road map. Some people do not need road maps. Not me.

post-5682-1274571268.jpg

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Sometimes the body "springs" when the top is removed. This can be corrected for by putting temporary braces inside the body in critical spots. The braces are cut to the right length to support the body's correct width when it was mated to the top, but must also be cut thin enough that they can be broken and removed through the F-holes or end pin hole after the top is safely back on.

The best way to cut this kind of support brace would be to to cut it across the grain, not with it, on a scrap of spruce from your last

instrument top carving project. Make a stick out of this wood with the grain running across its width rather than down its length

and it will be pretty easy to break when the time comes. You can tie a string to the middle of the brace and lead it out the end pin hole, or you can stick a rod in the end pin hole and snap the stick. Whatever you wish. Just make sure that the bracing sticks are

in fact small enough to be extracted through either the F-holes or end pin hole.

Chris

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Sometimes the body "springs" when the top is removed. This can be corrected for by putting temporary braces inside the body in critical spots. The braces are cut to the right length to support the body's correct width when it was mated to the top, but must also be cut thin enough that they can be broken and removed through the F-holes or end pin hole after the top is safely back on.

The best way to cut this kind of support brace would be to to cut it across the grain, not with it, on a scrap of spruce from your last

instrument top carving project. Make a stick out of this wood with the grain running across its width rather than down its length

and it will be pretty easy to break when the time comes. You can tie a string to the middle of the brace and lead it out the end pin hole, or you can stick a rod in the end pin hole and snap the stick. Whatever you wish. Just make sure that the bracing sticks are

in fact small enough to be extracted through either the F-holes or end pin hole.

Chris

++++++++++

Thank you.

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Freehand is exactly how it's done. There are always little discrepancies on how the ribs fit, and these have to be nudged and tweaked into position as the top is glued and clamped. Summer workshops are a great way to learn these skills under the supervision of expert luthiers.

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Hi all,

It is not a simple procedure. I have seen a few tops glued back ( I do not know who have done the jobs) in such terrible fashions.

Over hangs (edge) are uneven. They probably did it free handed. I do not think that is the way (free hand) to do it.

What is your usual way? (I have to use pin holes)

Clamp the whole thing on with spool clamps. Dry with no glue. Get the corners as close as you can and then glue maybe 10cm of the C-bout. This will be about three clamps worth. Take off the other clamps and leave the six in place. Tease the corners into place and glue them one at a time. When the corners and C's look good, you can bend things to get the end blocks right. Finally, the bouts are glued. You may STILL need to push on part of the ribs to even out lumps.

Sounds like a lot of work, but I find it works fine. Warping usually does not involve anything that cannot be undone with this can of man-handling.

Pin holes? I never use pin holes.

Well what DO you do? I have to say that I don't like Fellow being treated like the village idiot. He seems a nice enough guy. Why not just give him some advice and let him have his hobby.

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This blog that I have been following has a video of the plate being glued on.

http://thequartetofpeace.blogspot.com

See the section titled "Wednesday, April 28, 2010

Assembling the violin ... "

If you are interested in seeing the other videos, they can be found at the makers web-page.

http://www.violinafrica.co.za

Just click on 'Videos' on the left hand side of the page.

I like the one that shows the plates being jointed and the squeeze join being employed with no clamping needed.

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Hi Fellow,

John and Doug are right on this method. One of the first thing I learned was to prepare all your clamps ahead of time and do a "dry run". With all the clamps in place and getting all the edges adjusted as carefully as you can, one small section can be glued at a time, avoiding surprises. I tend to glue first the areas that are most sprung out of position as the other sections will fall into place almost automatically.

Try to use just enough glue for the job and you'll have less to clean off later. Once the excess glue had gelled you can remove most of it with a softwood stick sharpened to an angle to get into the corner between the border and the edge (light fingered work, so as not to damage the varnish). If the varnish is really tough and waterproof you can use a very small "damp" glue brush.

If the fingerboard is still on the instrument you need a device to get some clamping pressure over the neck block, underneath the fingerboard. You can easily make up a counterform the shape of the neck block, but slightly curved towards the side that goes against the table. In this way when you tighten the clamps on either side of the fingerboard the curve will give you some pressure at the center of the block area where it must glue up well for structural stability.

Let us know how it goes,

Bruce

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++++++++

Yes, it ran well.

In fact, when I posted this question, I have already glued the whole top with all cramps on.

I did it section by section, it took longer than I expected. The was quite good in my standard.

I used the pin hole at the neck first and dry fitted the upper corner, then lower coners. I positioned the

pin hole at the end block. It fits nicely, so I had confidence that when glue is appliedit won't be uneven.

As it turned out the result was almost exactly I expected. Without the help of pin hole I would be horrified

if the last section was out of line too much, I hate to break up glue, dry or wet.

Thank you , nice people.

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I did use this procedure where the plates and the ribs/lining gluing surface are glued the left to dry. Then like in the video the plate is aligned with the garland then slightly clamped. Using a very fine knife or palette dipped into boiling water. The water will remelt the glue. It did work very fine and you don't need pin hole in this way.

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++++++++

Yes, it ran well.

In fact, when I posted this question, I have already glued the whole top with all cramps on.

I did it section by section, it took longer than I expected. The was quite good in my standard.

I used the pin hole at the neck first and dry fitted the upper corner, then lower coners. I positioned the

pin hole at the end block. It fits nicely, so I had confidence that when glue is appliedit won't be uneven.

As it turned out the result was almost exactly I expected. Without the help of pin hole I would be horrified

if the last section was out of line too much, I hate to break up glue, dry or wet.

Thank you , nice people.

I think you'll find that the pin holes are not necessary for regluing the top on (or the back, for that matter) once you have everything lined up and you glue one portion at a time.

I never did like the idea of drilling more holes in violins and it really is unnecessary.

Bruce

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I think by saying "pin holes" you mean registration holes/pins. It is perfectly fine to use either technique.

Some violins simply have uneven overhang, so don't assume that by removing the top it will align properly, or that you will be doing the violin a favor. If the instrument is fine, don't mess with it simply because you want to "improve" it.

When I was a kid, I noticed that the upstairs toilet tank wasn't parallel with the bathroom wall. Since I didn't know any better, I thought that I could give the toilet a tweak, and straighten it out. I gave the whole works a quick twist, and later discovered that I had broken the wax seal at the base of the toilet... slowly flooded the bathroom, destroying the flooring etc. My parents were thrilled.

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Clamp the whole thing on with spool clamps. Dry with no glue. Get the corners as close as you can and then glue maybe 10cm of the C-bout. This will be about three clamps worth. Take off the other clamps and leave the six in place. Tease the corners into place and glue them one at a time. When the corners and C's look good, you can bend things to get the end blocks right. Finally, the bouts are glued. You may STILL need to push on part of the ribs to even out lumps.

Sounds like a lot of work, but I find it works fine. Warping usually does not involve anything that cannot be undone with this can of man-handling.

... .

John, I wish you told me this years ago. Very clever.

Mike

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When I was a kid, I noticed that the upstairs toilet tank wasn't parallel with the bathroom wall. Since I didn't know any better, I thought that I could give the toilet a tweak, and straighten it out. I gave the whole works a quick twist, and later discovered that I had broken the wax seal at the base of the toilet... slowly flooded the bathroom, destroying the flooring etc. My parents were thrilled.

They could have at least praised your good eye for alignment! :-)

Good ideas presented so far. One thing I do is put the old bridge on the top with rubber bands, which allows me to eyeball the fingerboard projection. Of course, one has to have the bridge in hand and assume that it was at the proper height prior to taking the top off.

Unless you can talk them into a new bridge, too!

Cheers,

Ken

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I assume we are talking about a top that's been taken off and is now being glued back on. I've usually found that how well it fits back on has a lot to do with how cleanly it's been taken off. Almost always the tops I've removed fit back neatly with no realignment necessary. In fact (and I'll probably catch some heat for admitting this) sometimes if the fit is quite nice, I don't even bother with the spool clamps anymore, just grab a big handfull of heavier rubber bands, lay the plate on the glue and strap her down! Never had a problem doing this, and the plate is quite smoothly aligned. Sometimes though there is some spring in the garland of older violins when the top is removed, and so this 'quick-n-easy' method doesn't work. When that's the case, I use a method similar to what Johnmasters spoke of.

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