Restoration of a G. A. Carlson Harp Guitar

The Guitar

This is something I meant to do over a year ago when I first worked on the guitar but it fell by the wayside and I've just now gotten around to putting it together. Read my research on Carlson here: https://www.snathanieladams.com/2024/06/g-carlson-chicago-illinois-1896-1902.html

I don't do much work for hire, I mainly work on instruments that I've purchased in project status, I repair them, and then I put them back out into the world for people to enjoy. But I was approached by a collector and dealer whom I've bought many guitars from, he explained that he picked up this unique harp guitar and wanted to know if I could put it back together. Harp guitars have always fascinated me and this is the kind of project that I enjoy coming across. Original finish and hardware intact, my least favorite thing to recreate, but plenty of structural damage to address.

From the front, there really isn't anything scary about the guitar. A couple hairline cracks, a loose bridge with a completely wild tailpiece design, and a missing tuner button. Once the guitar is flipped over, the detached back shows evidence of water damage and a previous repair attempt. There is a good amount of structural work needed to get this guitar back together

Repairing the Back

As mentioned above, the birdseye maple back was split along the grain (figured wood has squirrely grain) and glued back together with the proper clamping pressure. The pieces of wood are not tightly bonded together and there is a lot of glue filling gaps that should've gone together cleanly.

The repair process starts by testing a small spot with De-Glue Goo (a gelled vinegar solution used for dissolving wood glue) to confirm that it won't interact with the finish. This guitar is french polished and the vinegar does nothing to it. I saturate both sides of the crack with the 'goo' and let it sit to start breaking down the wood glue. It required an application of warm water and gentle heat from a heat gun before I was able to break the boards apart. Then, an unfortunate amount of time spent scraping glue residue...

I realign the cleaned boards, apply some glue, and clamp the devil out of the joint so everything is flat. I use a piece of acrylic as a caul because it's incredibly flat and glue doesn't bond to it.

After gluing, the crack disappears except in raking light. I'm thrilled with the result but we're still stuck with a gaping hole.

I cleaned up the edges and inlaid a new piece of maple into the void and tinted it with shellac. It's enough to not look glaringly broken.

The Sides

The sides on this guitar are thin and the reversing grain of figured maple offers a multitude of places for cracks to appear. A previous repair involved soaking mesh sandpaper in wood glue and papering the cracks with these strips. I'm skeptical of the shearing strength of mesh sandpaper and a couple of the cracks were misaligned so this work needs to go.

We grab the bottle of De-Glue Goo and get to work on breaking down the globs of glue on this guitar. A nice chisel found itself working on the horrid task of separating the sandpaper from the sides

In total, I had to repair 23" of cracks in this area and I reinforced them with spruce cleats along the cracks as well as adding four spruce struts to stiffen the area. I was able to break and realign most of the cracks. 

On the other side of the instrument by the neck block, there's another repair done with fiberglass and a mystery glue. It was solid so I left it.

The Bridge

The bridge on this guitar remains one of the coolest designs I've seen, a beefy brass plate holds four arms which run through the bridge and are secured via split-slot nuts sorta like you'd find on an old Sheffield handsaw. Time and tension are the enemies of a guitar bridge and it's remarkable to find that this one is still intact although the guitar side did suffer some shaving.

What is even more surprising is that this bridge has never been reglued before, it still has all of the original hide glue which has gone brittle and failed.

Is it weird to say I was super excited when I found beard hairs in the glue? Just a little piece of Gustav

The bridge is made of a wood that appears to be mahogany but it's quite hard. Not like a rosewood but rather like a really dense piece of mahogany. I scraped it clean in preparation for regluing.

The previous work at lowering the strings involved filing off some of the material 

I brought the damaged areas down and patched new mahogany on top of the bridge. The profile of the bridge puzzled me for a while because it's radiused but it doesn't match the fingerboard nor is it consistent. The high E and B strings are considerably lower than the lower four strings. I didn't have a lot of material to go off of so I gave it my best approximation.

Once on the guitar and tinted with shellac, the bridge starts coming togther.

The Necks

The two necks are bonded at the top and are made of mahogany. I needed to replace two of the tuner buttons and I prefer the translucent white buttons that WD Music sells, I believe Gotoh makes them. I didn't tint the buttons as I've experimented with alcohol tinting and haven't gotten consistently good results to want to try it here.

The neck block situation is interesting, unsurprisingly they are saw cut dovetails but the cuts are wildly off center from the necks that they mate with.

The guitar neck had a loose fingerboard which I popped off to reglue. There was a significant ledge between the mahogany of the neck and the spruce top which meant that the neck was set too far in the dovetail from the day of this guitar's construction. I wasn't going to pull these necks 

The ebony fingerboard had circular saw marks on the bottom and some considerable gaps where the wood wasn't contacting wood. That took some sanding to prep the surfaces for the reglue.

To tackle the ledge at the body joint, I laminated a piece of mahogany to the fingerboard and started tapering it away towards the nut. It was no thicker than 1/16 of an inch at the body joint (the abrupt end you can see at the bottom)

The Tuners

There wasn't any work needed here but I wanted to call attention to the work on this headstock. The piece joining the two necks is nicely carved and the tuner plate was elegantly carved. The nut for the bass strings was a single piece of bone held in place with two screws. The extra tuner looks to have been added to replace an original one that broke off. It's a little crude but works.

The tuners were nicely made and coated in a good amount of oxidation, those needed some cleaning with a bristle brush and relubrication.

Here is a look at the channel cut into the headstock to support the tuners. The flat head screw seen in the center actually connects the two necks together but I'm not certain if that was original or not.

Here is the extra tuning machine, it appears to be from the same manufacturer as the tuners on the 6 string neck.

I can't play the harp guitar like it was intended but I was able to play the six string neck and hit some of the bass strings. I went to Gregg Miner, of HarpGuitars.net, for advice on stringing and I purchased the strings from him. 

The saddle for the six string neck, if I recall correctly, was not in the right spot for intonation and I couldn't locate it while still being on the bridge. But I got it approximately where Gustav intended and called it good.