Torn Wood Grain Under Bridge

[Doug Miller]

The Bridge has lifted from my 2006 G3 acoustic 6 string. It is not a pegged bridge but rather a string through style bridge.

When the bridge lifted, it removed some wood fiber from the spruce top...the grain in the top seems to be running out towards the rear which could be part of the reason it lifted in the beginning.

This guitar is from a highly regarded luthier, but since I am second owner so he is unwilling to do the repair on warranty.

A local repairman/luthier would not repair it saying he thinks it should have a pegged bridge and with the torn wood grain it could never be strong enough in his opinion.

So I am left wondering what  to do and in particular...what, if anything, can be done to fill the lost wood fibre from the top?

Any comments from you luthiers and repair persons would be greatly appreciated.

Doug

[Greg Mirken]

A recess can be routed to remove the shredded spruce and a piece of spruce inlaid into the recess. If this is done with hide glue and the bridge then reglued with hide glue it should be plenty strong.

[Gary Fried]

I would begin by gluing those loose fibers back into place. I would then add some fibers to the remaining voids. After that I would level the area and bottom of the bridge and re-glue. I am not a fan of those types of bridges but a good repair should allow the original to be re-fitted and not come loose.

[Jim Bancroft]

I think I would use superglue to glue the pieces back down, then use wood dust and superglue to fill in any minor voids. Then totally level and flatten the gluing surface, and get as perfect a gluing joint as possible. Next, glue the bridge back on with hot hide glue.

Jim

[Doug Miller]

thanks for the quick replies gents. I spoke with the luthier who built this 16K guitar and he does not do repairs...but would replace the top for $1000.....if thats not a repair what is? His alternative is as Greg suggests...routing it out etc.

One luthier near me suggested it should have a pegged bridge.....any opinions? I see Gary is not a fan of these non pegged bridges.

[Kerry Krishna]

I am also not a fan of these. Did you ask the un-named Luthier, if this happens often with his guitars, as I sure would have... I have read on several forums that the bridge on a guitar like this functions quite  differently than a pin bridge, so you might take that into account too. What would be the problem with gluing the bridge back down as per above suggestions, then putting in a few bolts, and two abalone dots to cover the bolt heads? ( how many of you are cringing with me suggesting this?)

[Doug Miller]

Good point about the luthier Kerry...do I hear cringing?

[Kerry Krishna]

Doug, I would hope that he WOULD be forthcoming with info like that, although there are plenty of high end Luthiers that will not admit in public that mistakes have been made.There truly is a BIG place in my heart reserved for anyone being transparent about things like this.  I don't image that a 16k  guitar has been humidity abused or sitting in a hot car, or had 62 to 16 gauge strings put on it, so the bridge coming off? Well, it does happen even to Collings guitars a few times a year, so it could happen to any company, regardless of quality control.  I also wonder if he is still using this type of bridge, or has changed because of this exact problem. If this were my guitar, I would get hold of him again, and ask him what he thinks of a few bolts through the same bridge to hold it down, and also what he thinks about putting a pin bridge in.

[Mike Kolb]

After years of denying it, I'll now proudly proclaim: "my name is mike and i'm a fan of bridge bolts"....  Seriously, I've been putting bridge bolts in guitars for a long time, particularly in 12-strings but most any guitar that comes through the shop for bridge repair... and the pinless bridges almost scream for the extra help. Of course, this requires an OK from the customer, but the majority have no objections.

I use 4-40 stainless hardware and nylon-insert nuts with a liberal dose of Loctite on the threads. The customer has the choice of covering the bolt heads with either MOP or hiding them with a plug to match the wood. 

The procedure has no apparent impact on the tone and gives a good degree of "peace of mind".  No, I wouldn't do it to a vintage Martin or anything similar, but for the vast majority of the guitars that come-through the shop, it's insurance worth considering. 

[Russell Vance]

Hi Mike, 

I'm with you on this one, interestingly, I come from an engineering background which does not tolerate bad engineering, myths, prejudices and traditional practices and the bold face, heavy typing in my engineering handbook says "use a mechanical fastener when an adhesive will not do the job.   I think this kind of "engineering" qualifies for this use of mechanical fastening.   Particularly if you can hide the fasteners.

Personally, I'd like to hang the designers of such bridges offa a real high building attached only by their bridge design and then ask them if they would like a bolt or two to keep the bridge attached.  I'm also not fond of so called luthiers refusing to take responsibility for their (poor) design integrity - Unfortunately, I have seen way too much of poor design and execution to think anything else. Rusty.

[thefishinmusician]

I wonder if the builder finished the guitar and then scored and scraped the finish off to glue it. And scored it too deep..I've seen this on a lot of production guitars and have wondered if this may be the case a lot of the time....I've done a lot of Guilds that seem to have this happen....The clean break on the front of the bridge has always made me go Hmmmmmmmmmmmmmmmmmmm,........

[Doug Miller]

In order to remove the pulled up bridge with grain attached to it I had to cross cut the grain so it did not pull grain up beyond the bridge area.

I'm starting to think the idea of bolting the bridge down might be a good idea....not sure how many bolts I could get in and if I need extra wood under the top.

Perhaps Mike could give me more info on how he has bolted bridges.

[Mike Kolb]

Hi Doug... my standard procedure these days (if the bolting is needed and gets approved) is 2 bolts to the rear of the pins, one placed behind and between the E and the A pins, and another between the B and E pins (picture a "triangle" on each placement... with the pin holes as 2 points and the bridge bolt as the 3rd).

I'll first drill a hole (with a sharp brad-point drill) .250" in diameter, about .250" deep, followed by a .110" hole in the center of the larger hole, through the bridge. These two holes (for each bolt, of course) will accommodate the 4-40 machine screw shaft and head, leaving a fair am't for plugging the hole when done.  Make sure the holes will go through the bridge plate, which serves well as an anchoring point. Back-up the bridge plate with a hardwood block when drilling, to prevent split-out.

On the underside, install a flat washer, a lock washer and a nut. The best luck for me these days, though, comes with using a flat washer and a nylon-plug locknut with a drop of Loctite. Holds like crazy.

Two bolts toward the rear of the bridge seems to be plenty. That's where all the force is directed and they do little to disrupt the comings and goings of string changes. I keep a variety of lengths handy, but will usually end-up using 3/4" or 7/8" lengths to accommodate the thicknesses of everything and still leave room for the washer and nut but every case is a little different.

It's not a substitute for a good glue job, but it sure lends a helping hand to problematic cases (read: 12-strings!) and any other guitars where conditions for reattachment of the bridge are less than ideal.

On a personal note, I bought a used Martin B1 bass from a guy and got a great price because the bridge was lifting from string tension. I removed the bridge, reglued it, bolted it down and filled the holes with ebony plugs. That was 4 years ago and the bridge has not budged since, nor can the holes be seen readily and the bass sounds as good as it ever did.