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Dwight Brown

Repairing A/E string notch on bridge.

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Good Morning Folks!

 

Is there a prescribed method for repairing a bridge slot for the high string on a violin or viola bridge that has gotten too deep or too wide?  I should think the best thing to do would be to not be a cheap SOB and give my luthier some work!  That said, it is a 300 mile round trip to see him and that would equate to 600 miles driving to drop it off and pick it up :-(  I have more problems with this on violas than violins strangely.  I usually prefer to have instruments set up with a parchment patch and not to use the tube things at all.

 

I was thinking that perhaps filling the notch with CA glue and using accelerator to fill it might work then carefully filing a new slot?

 

I have a bridge on my usual violin that is stamped and I am pretty sure cut by Bein and Fushi that has a tiny little bone or mammoth insert for the e string that works quite well.  I have never seen another like it as the insert cannot be seen from the outside only from the top of the bridge. ( I probably don't get out much!)

 

I think I just served up some word salad, but it's early Monday morning and my kids are taking a practice test for their exam next week and it was quiet.

 

Thanks,

 

DLB

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I like the neat way that they inlay the little piece of ivor, er, I mean, mamoth.

 

If you have the ability to remove the bridge without risking the loss of the post, thick CA and a parchment will work. Without parchment or something over it, it will just cut back in.

 

In extreme cases, where i want to save the bridge, I use a knife to cut a little notch and scavenge old bridges to fill in the notch, but you still should cover it with parchment.

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I was thinking that perhaps filling the notch with CA glue and using accelerator to fill it might work then carefully filing a new slot?

 

 

I've never tried it but I think I've heard that it works well.  (My memory ain't what it used to be.  :-) )

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I know that I probably shouldn't admit to having done this, but, I've also raised the E string slightly, with a tiny ebony insert in the bridge, that is, besides simply using one to repair a too deep slot.

 

Very often a "student or beginner violin" cannot afford a new bridge, even if one is needed, and such a 'fix' can work perfectly well - for the raising the E string, in particular.

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CT is right, but I'd inlay part of a strip cut from a nut blank and leave the bottom edge square.  I've done this to save an epoxied pickup bridge before. You could also do a half-edge ebony inlay like Aubert has on their reinforced bridges, just extend it full back to front width at the top.  :)

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Perhaps C/A with ebony or maple powder as filler?  I agree that the ivor)&*^)*^)(*_( sorry )Mammoth is a cool way to go.  I have never seen it anywhere else.

 

As a teacher It really helps to be able to get a kids instrument up and running as it is such a trek to get  to the luthier. I think I have paid more for a first class bridge than some of the kids instruments cost.

 

I will practice on some cheap bridges and see what works.  I kind of think that the thicker gap filling C/A would work better perhaps using tape to keep it from going where you don't want it or perhaps a little wax to keep it from sticking where it should not.  It is evil damn stuff as far as going where you don't want it!  Leave instruments across the room from it.  I am no violin maker, but I have used lots of it building rockets and model airplanes, etc.  It also does a superior job ruining clothing.

 

DLB

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Hey Dwight,

 

If you're at all interested, PM me, and I'd be happy to send off a piece of Mammoth tusk AND a workable piece of ebony.

 

(No charge my brother. I'd be delighted if you accept)

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CA and parchment are fine if it's only starting to cut into the bridge. You can build up the notch with layers of CA, but you'll have to trim the excess. You can "varnish" the parchment with CA as well (not for wound strings). Don't get it too thick.

JMH(non-professional)O

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I have used wedges of ebony and that white ivoroid plastic that guitars use for nuts after using a file to cut a notch out of the bridge.

 

I'd like to get some 1mm diameter Delrin rod, so I can drill a tiny hole vertically and put the rod in virtually invisibly.  Delrin is great stuff for having the string slip easily over it, but it doesn't bond worth a darn.

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Would you consider JB Weld for filling a slot?  You're saying plastic inserts are ok, so it might be ideal.  The usual complaints about it are it won't hold up to 700 degrees and it's not fuel resistant :) 

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Haven't tried it yet, but I recently saw a pro guitar repair video on youtube where the guy used baking soda as accelerator and substance for filling a nut groove. He packed the groove with baking soda then added CA. Claimed it was hard as bone. I do plan to try it sometime on a violin bridge. The best part is the baking soda causes instant hardening.

 

He also demonstrated hardness by making a small separate batch and then whacking it with a hammer. It didn't break.

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From Michael Darnton, in a similar thread:

 

"Superglue. A little superglue, let it dry, repeat. If the slot is deep enough, glue the tip of a toothpick in the hole (in the same orientation as the string), then add a layer of superglue after the toothpick gluing has dried and you've cut off the extra and cleaned it up with a nail file."

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Haven't tried it yet, but I recently saw a pro guitar repair video on youtube where the guy used baking soda as accelerator and substance for filling a nut groove. He packed the groove with baking soda then added CA. Claimed it was hard as bone. I do plan to try it sometime on a violin bridge. The best part is the baking soda causes instant hardening.

 

He also demonstrated hardness by making a small separate batch and then whacking it with a hammer. It didn't break.

 

Along the same lines as that, in drugstores you can get fingernail repair kits that women use.  It is a plastic powder plus methyl methacrylate liquid.  Combine them and it's workable for a minute then hard as nails...

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Years ago I experimented with some different materials to prevent the E from biting into the bridge. Bone worked well, however I found phenolic that I scavenged from an old printed circuit board was easier to shape and glue. The phenolic is hard, relatively light in weight. The piece I added was perhaps 1mm high by 2mm wide.

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For the most part, I clean up the bridge notch with a file a little bit for good adhesion, take a few maple shavings, coat them on all sides with glue, and insert them under the string to clamp them in place. When dry,  trim the excess, and widen the notch a bit if needed.

Depending on the situation, it's also nice to insert a piece of waxed paper or aluminum foil between the string and the gluey wood insert, to avoid glue sticking to the string, or impregnating a wound string.

 

I'll need to try the soda/super-glue thing.

 

What I've found so far, is that hardness doesn't relate all that well to wear resistance. Animal skin drumhead is one of the most wear-resistant materials I've ever run across, in the bridge-protection realm, though it isn't very hard. I've also tried much harder materials, which didn't do as well.

Filling bridge notches with superglue alone hasn't worked worked out all that well for me. It's quick and easy, but doesn't seem to have nearly the resistance to wear that I'm looking for.

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David Burgess: 

 

What a great idea using the actual string/bridge as it's own self-contained mini-vice!

 

Sounds like for students and mere mortals the superglue/soda might work, but you might need to add parchment over it. I'd be interested to hear how it works for you.

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Example of ebony notch.

I cannot see any sense in inlaying the ebony patch beside of the string path, regardless on the really ugly bridge as a basis for the inlay. Just my two coins here.

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One of your coins are spot on; neither bridge or violin is pretty, (and it's not my work.) It is still an example of a ebony notch thou. Why they put it where it is, if the string was positioned differently before is anyones guess.

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