Bowlback separation

[Jim Baker]

Hi All. I recently bid on and won a very old Italian bowlback from the auction by Chris Logan. As expected it needs repairs.
It has a separation between staves on the bowl and, more seriously a separation between the top and side almost the full length.
Most stringed instruments have a gluing strip added at the joint between the side and top. This instrument does not.

Two questions: 1) Should I remove the top? 2) Should I add a gluing strip in order to strengthen the joint?

Pardon my ignorance of terminology.

Many Thanks

Jim

[Bill Snyder]

Just for your information the gluing strip (good descritpion) is generally called kerfed lining or (shudder) kerfing.
If the top is already loose almost the entire distance around I would certainly think about taking the top off and installing some lining, but I am not a repairman just a wannabe, amature, builder.
Some high res photos might get you better advice.
Good luck with it.

[Jim Baker]

Thanks Bill. Good idea. Now, If I can figure out how to do that....

[Jim Garber]

Hopefully Dave Hynds will chime in sometime. It looks like there is some separation of the top from the bowl but there is also that crack. I can't tell if the crack is warped or just that the knife is causing that to look that way. If warped then you will probably need to humidify the instrument to flatten the top. I am certainly not a repair person so I could not tell you in which order to do what.

Ideally, in these cases of the old Italian ones, you will definitely need to remove the fretboard -- at least the end of it -- before removing the top. These fretboards are usually pretty thin and may flake away altogether. I think the recommended way to remove the fretboard is with a hot iron to loosen the glue and a sharp knife and tons of patience to remove it. More than likely you will have to replace the fretboard anyway, even after all that. It might also be a way to have the bridge higher so to increase the string angle.

Good luck!!

[pjlama]

I think the big Buck knife in the top is the problem


Sorry, I couldn't resist.

[Jim Baker]

Actually there is no warpage. It's just an optical illusion. If there was a way to glue it without removing the top, for sure I would do it. I'm just worried that it would not hold under string tension.

[Jim Garber]

Frank Ford's site has some good articles on crack repair. The closest I could find was this one on Fixing a Ukulele crack. Maybe that can help. I think the most difficult part is finding the proper clamps.

[Jim Baker]

Thanks Jim. I do have a long separation between staves on the bowl. I think it is caused by drying out over time. My intention is to make a sliver to fit the split and glue it in. Only question I have with that is what type of wood to use.

[dave17120]

Hello Old Jim, Old Dave here....... had freinds for a few days, or would have picked this one up sooner.

Taking the top off is not too difficult if its faily loose, especially as you say it has no lining (gluing strip).

Beforehand, check the width of the split.

Step 1. take out fret 10, and carefully saw through the fingerboard and top in the fret slot.
(trying to get thin f/bs like that off, is very hard without losing it all)
Step 2. slide your flat palette knife in under the edge, and gently and carefully lever the sides off. Be particularly careful around the ends of the struts, which may or may not still be glued.
Step 3. if you like, post a couple of photos so we can see what you need to do next...... which will partly depend on how the dis-assembly goes.

Hope that helps a little.
Also you might my site useful, www.mandolinluthier.com

Keep us posted, Dave

[Jim Baker]

Thanks Dave. I sure do appreciate your input. Are you suggesting I will need to remove part of the finger board along with the top? Will this take away from kneck strength?
Will I need to heat to soften the glue?
I'm away from home right now, so will not get to it for a few days. (assuming I have the nerve to start it).
The knife you speak of. Do you mean a putty knife? Can I substitute with a thin paring knife?
Do you agree that I should add a "lining/kerf/gluing strip" in order to strengthen the joint between the sides and top?

[dave17120]

Hi Jim, a few answers.............

yes, you remove the end of the fingerboard still attached to the top. No it shouldn't affect neck strength, as you will glue it all back on again. The fingerboard does not affect neck strenght much anyway in these old ladies.... many are so thin that they have to be cut right through to fit the frets.

No if you are not taking the fingerboard off, you should not need heat. I have found with a little teasing, the top pops right off, the most difficult bit, which you need to do last, and then from both sides alternately, is the bit of the top glued to the heel, below the fingerboard end.

Knife..... I use a narrowish wallpaper scraper, with the sharp corners rounded off. Seems to do the job.

And yes, if it was me, and I have on several occasions, I would add a lining before re-gluing the top.

All the best for now, Dave

[Jim Baker]

Thanks Dave. I'll keep you posted

[Jim Baker]

Oh! two more questions Dave: 1) What is the best material for the lining strips? 2) What glue do you prefer? Thanks again.

[dave17120]

Hi Jim, if you can get it willow is very good as its flexible, but maple works. It ought to be about 3mm thick with the grain running longways.... your only problem, if you are not a luthier, will be bending it. Cut to length first. Keep it wet, and keep applying heat.... when you are roughly the right shape, clip it to the bowl with clothes pegs to set to the perfect shape before gluing in.
Good luck, Dave

[dave17120]

Oops, mis-read that....... glue!! Obviously hide glue is authentic. Clean any old glue off first and don't mix too thickly, but you may not have it.I also use Cascamite.... a lot depends on the linings, so you don't want them to come loose. Works well and has a user friendly 'curing' time.
Dave

[Jim Baker]

Thanks Dave. I see that some things are available from Stewart MacDonalds. I put in an order when I've worked out what I need.
I still need to figure out how to clamp. Likely not a simple matter considering the bowl.

p.s. I picked up #a piece of well aged ebony at a little music shop. I need to make a new bridge for another old bowlback. I was thinking of adding a bone saddle, but I guess that wouldn't be original.

More pictures soon.

Thanks again.

[Jim Baker]

Hi again Dave. I just got home and took a look at the finger board. It looks like the top runs beyond the 10th fret. Do you think I should cut back at the 9th fret? See image.



Thanks

[dave17120]

With regard to clamping the back..... I've not seen a nice simple 'clamp' for this, and believe me I have tried a few things!! Now I hold the crack together with strong finger pressure, and apply masking tape acroos the crack. It stretches a bit and holds it quite well........ then, I re-enforce the pressure with a few nice thick rubber bands. Works fine, cost next to mothing. If you are worried, raid the wife's embroidery box for some cross stitch or tapestry fabric..... glue a thin strip inside lengthways along the crack..... similar technology to the stuff I've seen strengthening braces on Yamaha guitars.

Ebony is good for the bridge.... they tended to have bridge and f/b material match, but it doesn't really matter. Bone or brass rod saddles are both common.

You'll have to explain what you mean by run-out..... not too sure. But it does look like your 11th fret may have lifted a bit. Lay a metal ruler along the fingerboard and see if you have any dips.... also, do you have much room for a bridge if you hold the ruler about 2mm above the 12th fret???

Cheers, Dave

[Jim Baker]

Hi Dave. Sorry for the delay. Been out of touch. The fret you see raised is the 10th fret. I began to lift it and and then realized if I cut it there it will not capture all of the top. Should I move back to the 9th fret and cut it there?
I bought some hide glue and I'm going to make the lining out of some well aged basswood I've had for years. Before I tackle this instrument I'm going to do some repairs to another one with less damage. Hopefully I'll learn some tricks about clamping.

[dave17120]

Its always difficult to tell exactly wehere the top ends..... I always cut at 10, cutting carefully through the top as well, otherwise you have the problem of the narrow bit protruding up the fretboard which causes other problems. For me fret 10 is fine, it will be well inside the limit of the heel. The top can be carefully prised off with the end of the f/b attached. Dave

[Jim Baker]

Do you think the binding will stay with the top? Otherwise I guess I need to look for some rosewood to make a new one.

Thanks

[dave17120]

If you are lucky AND careful, the top should come off in one piece, with binding/edging, give or take the odd chip. Carefully save any brittle bits that come away.... you can reglue. BUT........ no guarantees

[Jim Baker]

Well, I took the plunge. The top came off fairly easily, but I wasn't able to save much of the binding.

[Jim Baker]

Now, I need to repair some of the ribs on the top and a piece that had split away on one side.

[dave17120]

Mark the position of the top struts carefully with a pencil before you take them off, otherwise its hell's own job trying to get everything in exactly the right place afterwards for re-gluying. That includes a pencil line drawn down the strut, and onto the top, at right angles to its length, so that you can locate it laterally later. Good luck, Dave

PS how about photos???