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Florian

re-joining center joint

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While working on my first violin i managed to crack open the center joint on the back. apparently it wasn't glued well enough. Is there any way to repair this, or do I have to spend 100$ (wood + shipping and import tax) to get new wood?

 

 

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Hi Florian. Why not try to reglue it first. I don't know what a real restorer would do so wait for other replies but I would remove the upper and lower purfling, reshoot the joint with a very sharp and fine block plane, pre bend two short lengths of purfling to help register the seam and reglue it on a flat surface with clamps. Use strong glue in a hot room. You will need to carefully remove the short registration purfling and replace it, perhaps use a scarf joint and save yourself the time of redoing the corners. Perhaps cleat the seam? 

I'm looking at this on a phone, your work looks worth saving.

Good luck,

Pete

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You should certainly try to re-glue i think ... make some sort of jig to make sure everything stays in place while clamping. Cleats on both side could work, you can remove them afterwards.

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Hi Florian - why not install a set of inside cleats on one of the half-plates. Fit a matching set on the same plate on the top side. That should line everything up for gluing. After 24 hours remove the top alignment "wotsits" with a sharp chisel and warm water.

Stretchy masking tape for light clampiing, edges held flat  on a flat surface with odd loose weights.

Don't touch the joint as it should be a perfect match already.

cheers edi

Hi EmilG - your reply appeared while I was editing my post - great minds....

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On the inside, install alternating cleats pre-glued to each side of the join. This zippers it together when you glue join the seam. You will probably have to use a number of the threaded rod type crack repair clamps to pull it together and hold it while the glue sets.

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I would be hesitant to glue cleats on the outside surface at this point, as it will leave glue marks. These could always be scraped away, but it will also diminish the available glue bond surface area and thin the plate around the center join.

If you're not finished thickness graduating the top, go for it.

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Just now, Bill Yacey said:

On the inside, install alternating cleats pre-glued to each side of the join. This zippers it together when you glue join the seam. You will probably have to use a number of the threaded rod type crack repair clamps to pull it together and hold it while the glue sets.

Mmm - three great minds - way to go!

If you don't have threaded rod type repair clamps - screw some blocks onto the flat surface - about 4 down each side and use wedges - quicker and they work in situ like a charm.

Don't have wedges? What do you do with the offcuts from the plates?

cheers edi

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5 minutes ago, Bill Yacey said:

I would be hesitant to glue cleats on the outside surface at this point, as it will leave glue marks. These could always be scraped away, but it will also diminish the available glue bond surface area and thin the plate around the center join.

If you're not finished thickness graduating the top, go for it.

Hi Bill - I would be surprised if there was no scraping necessary - if only to ensure a perfectly smooth finish. We should be talking of less than 0.002" or 0.05mmm. That shouldn't be a train smash.

On glue marks - cleaning away excess glue from the ribs after gluing on a plate never seems to leave glue marks.

When fitting a bass bar I glue in location blocks to ensure consistent fitting. After gluing the bass bar I chisel the block away until a hair-width  from the plate, then use warm water to remove the last of the block and wipe dry with a paper towel. Never a stain to see.

cheers edi

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This happened to one of my first instruments before I had a proper glue setup.  
I use one of these now.. https://www.ebay.com/itm/Single-Pot-Wax-Heater-Warmer-Machine-Professional-Depilatory-Salon-Hot-Paraffin/312077158169?epid=9004446404&hash=item48a93f8719:g:xH0AAOSwKcdZyhtC

Also, make sure the surfaces are a perfect fit when jointing the back.  No light should get through when you hold it up to a lightbulb. 

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3 hours ago, Florian said:

While working on my first violin i managed to crack open the center joint on the back. apparently it wasn't glued well enough. Is there any way to repair this, or do I have to spend 100$ (wood + shipping and import tax) to get new wood?

 

 

 

Assuming the joint fitted when you glued it originally, you only need to wash the old glue off, let it dry overnight, and then re-glue it.

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thank you all for the replies! Do you know any good articles on making cleats? I'm not really sure what's important to think about when making them. I'm talking about the cleats you make after glueing, not the temporary glueing alignements.

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13 hours ago, edi malinaric said:

Hi Bill - I would be surprised if there was no scraping necessary - if only to ensure a perfectly smooth finish. We should be talking of less than 0.002" or 0.05mmm. That shouldn't be a train smash.

On glue marks - cleaning away excess glue from the ribs after gluing on a plate never seems to leave glue marks.

When fitting a bass bar I glue in location blocks to ensure consistent fitting. After gluing the bass bar I chisel the block away until a hair-width  from the plate, then use warm water to remove the last of the block and wipe dry with a paper towel. Never a stain to see.

cheers edi

Depending on what Florian uses for sizing, glue ghosts may show up in the finishing process. With the bass bar being inside, it's of little consequence if there is a little bit of glue residue left behind.

That's all I was alluding to in my comment.

Edit:  Cheers to you too. I just started my first vacation today since 2004. We arrived in Invermere, British Columbia this evening. It's a 20 minute drive to Radium Hot Springs; I'm looking forward to a nice soak in the hot water tomorrow-    Hot mineral water, 0C cold mountain air.  Until then I'm sitting back and enjoying a nice glass of Panama Red overproof rum.

https://www.tripadvisor.ca/Attraction_Review-g182160-d284694-Reviews-Radium_Hot_Springs-Radium_Hot_Springs_Kootenay_Rockies_British_Columbia.html

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It would be good if you could figure out why your glue joint failed before trying again. Were the mating wood surfaces “perfect”?  Is your glue high quality? Did you overcook your glue?  Did you have the glue at a good viscosity for a permanent joint? Was the wood heated? Was the room hot enough? Did you get your clamps on quickly enough? Did your clamps draw the joint tightly? Did you let the joint fully cure before you started roughing it out?

I would find an old (meaning not new or green wood) 2 x 4 (framing timber) and practice making joints on that. After you prepare nice mating surfaces and glue them, cut and/or plane the wood into slabs of near violin plate thickness, and then break them apart.  If they break cleanly at the joint, your glue job isn’t good enough.  If they break away from the joint, your glue job is fine.  If they break right around the joint but with a significant number of fibers having pulled free from both sides, that’s probably ok (IMO).

 

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1 hour ago, Bill Yacey said:

- snip -

Edit:  Cheers to you too. I just started my first vacation today since 2004. We arrived in Invermere, British Columbia this evening. It's a 20 minute drive to Radium Hot Springs; I'm looking forward to a nice soak in the hot water tomorrow-    Hot mineral water, 0C cold mountain air.  Until then I'm sitting back and enjoying a nice glass of Panama Red overproof rum.

https://www.tripadvisor.ca/Attraction_Review-g182160-d284694-Reviews-Radium_Hot_Springs-Radium_Hot_Springs_Kootenay_Rockies_British_Columbia.html

Hi Bill - that sounds like something I could enjoy. My back has been giving me hell for the last 63 years or so - some days are better than others - like every third day or so.

We have a couple of hot springs around the place. Can't bring myself to get enthusiastic about visiting them.

We had an earthquake here in 1969  and one side effect at the nearest hot spring was that the "hot" of the spring disappeared. Our consulting firm was approached to "put matters right" and save the "health spa" from losing its clientele. We cunningly slipped in some diesel fired boilers and restored the heat to the spring waters. Business boomed.

The second is about 4 hours drive away. On seeing how we had upgraded the performance of the previous spa, this one approached us to work a similar miracle for them. The water analysis didn't do anything to make me eager to try it out.

Enjoy - have a shot of slivovitsa (plum brandy) for me -  only one now. After the third you'll levitate and launch yourself naked through the snow - don't say you weren't warned.

Of course you might not have access to the genuine article. However in Croatia brewing it is the national pastime - good stuff - doubles as paint stripper, high energy rocket fuel etc

cheers edi

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The OP tells us that this is his first violin. One should avoid the temptation to make him more unsure than he is aleady. Re-glueing a back joint is a relatively routine repair job (I have to do one this morning), so no big deal. As said above, wash old glue off, wait till it's absolutly dry, and re-glue. No big drama.

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8 minutes ago, jacobsaunders said:

The OP tells us that this is his first violin. One should avoid the temptation to make him more unsure than he is aleady. Re-glueing a back joint is a relatively routine repair job (I have to do one this morning), so no big deal. As said above, wash old glue off, wait till it's absolutly dry, and re-glue. No big drama.

how do you clamp it? tape?

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33 minutes ago, jacobsaunders said:

The OP tells us that this is his first violin. One should avoid the temptation to make him more unsure than he is aleady. Re-glueing a back joint is a relatively routine repair job (I have to do one this morning), so no big deal. As said above, wash old glue off, wait till it's absolutly dry, and re-glue. No big drama.

Exactly.

I managed to split back joint open when I was final scraping inside surfaces and used BIT more pressure than adequate.

I did zipper of cleats inside  and pillars with several small clamps to clamp it tight (there is no need for high force if the halves didn't warp). Fresh hot hide glue fast clamping and the joint as as good as before. I skipped the washing as I did it immediately after it split and there was no apparent layer of old (hide) glue or any dirt to wash off.

My first question would be what glue was used for the joint. If white glue or titebond (beginners often use that) then you NEED to clean old glue with water and/or vinegar (or use de-glue-goo) and let dry. Do not soak wood or the joint will no more fit well.

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I wouldn't underestimate the difficulty of doing this well. Fortunately, this instrument isn't varnished yet, so some minor mis-allignment can be taken care of with a scraper.

When plates are carved and thinknessed, some of the internal stresses in the billets will be relieved or will have changed, so shapes and dimensions can change when they come apart, and things don't always come back together easily. On older instruments with significant soundpost distortion on the back,  getting a centerjoint back together in a way that the repair isn't conspicuous can be a nightmare.  For instance, one side may be longer than the other. So if you manage to get perfect alignment on one end, as well as on the two sides of the outside surface, you may find that the purfling no longer aligns at the other end.

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It is (he says) his first violin. If one chucks everything away and starts again whenever one has a small mishap, he will probably give up out of frustration. The first violin (not to mention the hundreth) is there to make all the beginer mistakes, so lets encorage him a bit.

 

BTW: I have the first violin of my Father, which he never finished for this reason. This violin was hidden from me for all of his life. Only after he passed away did I find it. I finished it off, and think it is pretty good. It has some things I would critisise, but so what

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I too have my first violin hidden in a cupboard, and would never show it to anyone.
Some years back, I rediscovered it while trying to find something else (which I never did find), and it wasn't quite as horrific as I remembered, despite the timid scroll carving and orange varnish.

That was 20 years ago, and because it got finished, I moved onto number two, three, twenty, feeling ok and wanting to try better. I still want each one to be better of course.
As Jacob wisely mentions, it's important to get one under your belt and move on. Despite what everyone hopes, the first ones are not going to be the masterpieces everyone starts out wanting to make, and a lot can be learned from things going wrong.

A clean separation of the joint should glue back together reasonably well, and if the plate was not finally thicknessed, then there is going to be some room for minor adjustments with a scraper.

Time to get the glue on.

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1 hour ago, Wood Butcher said:

 

Time to get the glue on.

Do several "dry runs" first, to see that the parts fit together reasonably well, and to get the routine down. You don't want to be figuring things out and futzing around after the glue has been applied.

This will also give you an idea how long it will take to position the parts and get the clamps in place, so you can adjust your glue strength and gel time accordingly.

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1 hour ago, Wood Butcher said:

I too have my first violin hidden in a cupboard, and would never show it to anyone.

I have mine "proudly" displayed in my workshop  . I revarnished and re seted my no.2 and no.3,  and donated to the kids that cold not afford an instrument.

Had a failure on a back joint just once, while finishing the gouging of the the inside of the back. I  reopened  it washed the glue away, dried it and reglued it in two stages. Top and back of the joint first, the rest in the second stage. 

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2 hours ago, David Burgess said:

I wouldn't underestimate the difficulty of doing this well. Fortunately, this instrument isn't varnished yet, so some minor mis-allignment can be taken care of with a scraper.

When plates are carved and thinknessed, some of the internal stresses in the billets will be relieved or will have changed, so shapes and dimensions can change when they come apart, and things don't always come back together easily. On older instruments with significant soundpost distortion on the back,  getting a centerjoint back together in a way that the repair isn't conspicuous can be a nightmare.  For instance, one side may be longer than the other. So if you manage to get perfect alignment on one end, as well as on the two sides of the outside surface, you may find that the purfling no longer aligns at the other end.

I had a belly come apart once; it was already carved.  Maybe my second or third.  Laying it flat on the table, it had a 3mm gap in the center.  The edges were flat but the center was spread out. I planed it while the edges were clamped to a board.  I glued them while they were still clamped on the boards.  No clamps, cleats, or anything, just a rub joint.  It worked great.  

But after that joining, the center bout was only just over 100mm, so I did have to make turn it into a narrow, "Early Strad" model!  But even that wasn't a disaster. Looking at it today, I see it says #5.  I see ALL KINDS of things I'd do different on it today.  Especially edgework; I've just started dealing with that. I don't see small details good; I need magnifiers.  That's the thing with violin making, at least to me.  I know if I do more I'll get better, and it is so much fun. 

But it sounds decent, and the strings are still in tune after many months!  It's so gloomy today, that even with the light on, the phone camera is too slow. 

20181001_091357.thumb.jpg.8d26e2a1f6ddecca099cc7a4f0b47e39.jpg

 

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