First, a quick history lesson. Allow me to introduce you to the infamous Martin F-1, an hollow-body jazz box briefly made by the C.F. Martin company from 1940 – 1942, at the tail end of Martin’s foray into archtop guitars. The F-1 and other archtop models by Martin weren’t able to compete with the more popular jazz boxes made by Gibson, Epiphone and Gretsch. This was primarily due to Martin’s inability to adapt their dimensions and designs to the different geometry necessitated by an archtop. Put simply, Martin was making archtops with flattop patterns and wood choices, while others– notably Gibson– excelled in the design of archtop instruments naturally due to their company history. (Most of this information can be found in The Martin Guitar: A Complete History, referenced here.)
I came across one of these when a collector contacted me for some restoration work. A number of back braces had come loose inside this vintage guitar. On a standard flattop acoustic it’s easy enough to go in through the soundhole and fix braces. However, with an f-hole guitar like this– not so easy.
Not wanting to remove the back made this a near impossible repair. However, there was also a body-length crack running down the back, shown below. This large crack made it possible to do everything at once, without the need to be invasive. The crack solved the puzzle. Read on!
The wires you see sticking out are thin-gauge guitar strings wrapped around each brace on the inside. The blue tape marks the location where each loose brace crosses the crack. I don’t have any pics of the inside due to bad lighting and no focus through the f-holes.
Each wire is looping around a brace and coming back out through the crack.
The loops are then strung onto this little device designed by Jerry Korki. They were originally made to fix large cracks while gluing cleats inside for reinforcement.
You can see how they’re being used (a little differently) here. This way, each device will tighten the string and pull the brace against the back. I’ve cut slots in some thin acrylic cauls to accept the strings. They will help distribute the pressure. The trick here will be doing everything at once. All three braces and the crack will need to be glued up and clamped all in one process.
It was a delicate glue job, getting the clamping pressure and alignment just right. The crack was loose enough that I was able to inject glue pretty easily. I got glue under the braces by going in through the f-hole with a butterfly needle attached to my glue syringe (and some other trickery.) Ultimately the job turned out good. Unfortunately, we didn’t do any finish work per the customers request.
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