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To follow up episode #22 When a Bridge Removal Goes Bad, I decided to also write an article on bad neck removals as well.

This neck removal was particularly hairy. I won’t get into why this was the case, but you can see the damage to the soundboard beneath the fretboard tongue was extensive!

Not to worry, though. Even this can be remedied!

This picture was taken after I had already removed the worst of the damaged wood from the front of the neckblock with a sharp chisel. You can also see that I had to remove a part of the fretboard graft, which is a flat graft that runs crossgrain beneath the fretboard tongue. This is the V-shaped cut.

 

In order to be able to re-glue the fretboard tongue to this area I need to patch in a pad of fresh spruce over the entire affected area. Also, since the fretboard graft was significantly damaged I need to consider the structural integrity of the area as well.

My first objective is to clear everything down to the glue surface of the neckblock, the fretboard graft, and the transverse bar. I am not going to use a dremel tool here as I did in #22 When a Bridge Removal Goes Bad. This is because it is difficult to support the dremel tool as I did in that situation. The location of the soundhole is a problem.

Instead I will carefully clear the material with a variety of sharp chisels and abrasive tools.

But first, as a protective measure, I need to make a cross-grain cut at the edge of the affected area, just before the soundhole edge. That way, as I remove material, the spruce cannot tear out along the grain lines and affect the area outside of where I am working.

I do this by drilling several holes with a tiny bit, and using either a large jeweler’s saw blade or a small coping saw blade removed from the saw’s frame to cut along those holes. You will notice that the cut is made just outside the transverse bar.

To clear the material I used a variety of sharp chisels, being very careful near the edges or, in some cases avoiding the edges altogether.

I used the sanding stick on the right of the picture for stubborn areas and to get into corners. The file on the left was used to square up and straighten the edges. And finally, small sanding blocks stuck with 80 grit, 120 grit and 220 grit paper were used to clean up residual glue and truly flatten the area in preparation for the patch.  I like my glue surfaces to be impeccably clean, flat and smoothed to 220 grit.

 

Now I can take on the structural concerns.

It would be difficult to just patch in a repair to the fretboard graft as it is. Also, in cases of extreme damage such as this, I would rather err on the side of over-bracing the area.

That is why I decided to first alter the neckblock to increase it’s contact area.

It is a mahogany bock, so in staying true to instrument’s construction, I found a mahogany scrap and I squared and shaped it to fit snugly in the truss rod access cavity. The scrap is glued in place a little bit proud of the surrounding surface so that it can be levelled later.

 

While it was clamped up, I drilled an oversized hole through the scrapblock, lengthwise, to open up access to the truss rod again. Doing this while it is clamped up prevents the scrap block from splitting apart.

Now I can more easily tackle the issue of the fretboard graft.

I put a significant bevel into the tattered ends of the fretboard graft (see the first picture). That way, I can put a corresponding bevel into the small spruce patches that I prepare (see the second picture). This creates a gluing surface for the repair and it allows me to easily clamp the patches so that they are nestled between the mahogany scrap and the fretboard graft (see the third picture).

After the glue dried, I levelled and smoothed the mahogany and spruce fills.

You may notice that a part of the soundhole is missing! Well, I got a little too aggressive when I was levelling with the thumb plane and a piece chipped out. Fortunately, I recovered the piece and it can simply be glued back in place later.

 

Finally, a spruce patch is fitted and cut to shape. Notice the hole in the middle of the patch. Because glue squeeze-out can be real problem if it gets near the finished surfaces, I drill a hole so that some of the excess glue can squeeze out into the hole rather than be forced out along the sides.

Was this useful? I would love to hear your questions or comments! I try to answer every e-mail I receive, so please be patient with me eric@ericschaeferguitars.com

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My Canadian friend brought me a Norman guitar with a lifting bridge, a belly bulge, and long run-out splits in the soundboard beginning just forward of the belly bulge. These are all symptoms of the same problem: too much tension at the bridge.

 

First, the bulge in the belly needed to be reduced, then the bridge removed and reglued. Finally cleats were installed on the inside of the guitar to patch up the splits in the spruce. I also glued a thin graft to the underside of the area that was worn thin by years of heavy picking.

I will save the details for belly reduction, removal of bridges, regluing of bridges and installation of cleats for another time. For Episode #22 I want to focus specifically on what to do between bridge removal and bridge reglue… when a bridge removal goes bad!

Not every bridge comes off clean. Even when you do everything right, some amount of tearout in the soundboard is expected. If the damage is minimal, which is usually the case, the bridge can be re-glued without any patching of the soundboard. If the tearout is significant enough to negatively affect the glue joint, then patching of the area is necessary. The patch may be the size of a dime or much larger.

In this worst case scenario the footprint under the bridge was affected throughout. I unfortunately never took a “before” picture of the damage, but take my word for it, it was bad!

Why did this happen? In this case, the lifting bridge had progressed so far, and in such a way, that the spruce had already begun tearing out before bridge removal even began.

My solution was to rout out the entire footprint of the bridge to a depth that eliminates 95% of the damage, and install a spruce patch.

I say “95% of the damage” because certain areas of tearout were so deep that it was neither sensible nor necessary to rout the whole footprint to such a depth.

 

I routed the pocket with a 3/32″ bit in a dremel tool and a Stewmac saddle routing jig. Any “sled” type device that fits a dremel tool will work for this. The saddle routing jig works particularly well because of the Baseplate Travel Stops and the Jig Reference Plate (see image below).

The Baseplate Travel Stops prevent me from accidentally routing beyond the area of the footprint. The Jig Reference Plate allows me to work my way from the front of the bridge to the rear in multiple, parallel passes by adjusting the Jig Guide Plate to the Jig Reference Plate and then resetting the Jig Reference Plate with feeler gauge tabs after every pass. I’ve borrowed the image below from Stewmac’s website. This should hopefully help illustrate what I am talking about, even though the picture shows the jig routing a saddle slot, which is it’s actual, intended purpose.

For the majority of the rout I do not have to adjust the Baseplate Travel Stops. It is only for the rounded section of the footprint in the back that I need to adjust the travel stops inward after each pass. The 2 curved sections of the footprint (indicated by the arrows) then have to be touched up carefully with a chisel and/or a razor

An oversized spruce patch is cut to shape and glued in place.

I level the patch with a thumb plane and fine-tune it with sandpaper on a flat block.

 

 

Once the patch is flat and level with the surrounding lacquer, I turn my attention to cleaning up the mating surface of the bridge.

Ordinarily for a bridge glue, I would sand the mating surface to the radius of the guitar top. The patch, however, has no radius, so the mating surface of the bridge is sanded flat on a granite block.

 

I relocated the bridge and clamped it in place so that I could mark the pin holes on the new patch and drill.

The guitar is now ready for a standard bridge glue-up.

After the Glue-up: Since the spruce patch sits level with the surrounding lacquer, rather than level with the wood of the soundboard, I made sure to seal around the bridge with brush on lacquer. You can also use superglue. Either way, it should be carefully applied.
Was this useful? I would love to hear your questions or comments! I try to answer every e-mail I receive, so please be patient with me eric@ericschaeferguitars.com

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