Martin O-15 Repair
Run Over by a Car · Returned to Life

One of my guitar instructors had this guitar on his wall. It was his mom’s guitar that he was playing in high school when one of his buddies ran into it with his car. It has probably been hanging on a wall for 20 years. He is still strongly attached to the guitar and would like to be able to play it again.

I offered to try and get it playable with the least amount of rework I can do — keeping as much of the original guitar, finish, and age as possible while still making it structurally sound.

Amazingly it is not in “that” bad of shape. The major crack on the top is repairable. There is a small section of the X-brace that lifted cleanly over the crack. The tone bar has completely popped off — just a thin shim of brace remains. With the large access port, the repair to the top should not be difficult to do well.

I want to do a visible repair of the missing and cracked parts of the treble side — replacing just the missing wood with new wood. My idea is to have a thin piece of bent Mahogany backing the cracked but existing side, then replace the missing side piece with a patch shaped to match the crack pattern. All of the work will be done with hot hide glue.

This is an O-15, not an 18 like I first said. I have the guitar on the bench and it looks like I might need to do a neck reset. I assume the O-15 has a dovetail joint.

The inside is really clean. I was able to get the top aligned and glued the smallest crack, working some hot hide glue in and then clamping. Luckily the rims are pulling the top together so the joint is tight with no clamps. Easy to get the clamps in through the access port.

Bit by bit I am making progress. I closed the cracks on the top and back and installed cleats to keep them closed. I made an insert that included a tongue to reinforce the intact but cracked area in the sides and kerfed linings to replace the missing linings and assure a good glue joint to the top and back.

I thinned an orphaned side to 1mm, bent it to match the curve, and started fitting the side patch. This is painstaking work — the patch has to follow the irregular crack line precisely.

After making an inside-out patch and rebending it, I decided to start fresh. I still had the other half of the orphaned side and it only takes a few minutes to bend into shape. I did apply a few things I learned on the first attempt.

It took a combination of a plane for the top and back edges, chalk, chisels, files, and sanding sticks to fit the inlay. I used fish glue to give me a bit more time to fuss around. Yes, I do work barefoot and in my pyjamas — retirement is great!

I played with the colour, trying Red Mahogany, tobacco brown, and a touch of black. The next day I sanded off everything and sanded into the original finish a bit more. I remixed the dye with less red and a bit more amber. It is not perfect, but looks OK unless looking right at it.

The repair is very solid. The guitar has a clean drum-like tap sound. I really should let the finish cure for another week or so, but I am not the most patient guy.

Here is the O-15 all strung up. It is a real instrument again.

The happy owner playing it. Still sounds like an old Martin.