Loose Classical Strut Repair
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This one is a Guild MK2. A student model from the 1960’s and it’s in pretty good shape for its age.
Struts, also called braces, are an integral part of the structural stability of the top of the guitar so this loose strut should be glued down to the top.
I traced the profile of the brace onto a scrap piece of hardwood and used a sharp chisel to shape the clamping caul. A piece of carpet tape (strong and thin double sided tape) attaches the caul to the clamp.
Hide glue is my glue of choice for this repair. It’s easy to clean up, has a strong initial tack and is more conducive to future repair work than aliphatic resin glues. I like Dan Erlewine’s trick of soaking an upside down pipette filled with hide glue in a hot water bath until I’m ready to use it. I’ll use a thin probe to work the hot hide glue into the open glue joint and quickly wipe up the excess glue with a paper towel dampened with hot water.
I’m careful to not use too much clamping pressure, only what’s needed to close the glue joint. I’ll lightly scrape the remaining hide glue from the top after I remove the clamps in 24 hours.
A medium sized block of poplar lined with rubberized cork makes a good clamping caul. The cork-lined face protects the finish.
I’ve used a sharp chisel to make a small wedge of mahogany. I’ll glue the wedge in between the notch in the mahogany lining and the end of the brace. This will help prevent the brace from working loose in the future.
I’ll let the glue cure for 24 hours before proceeding.
I’m using a razor blade to cut away the excess length of the wedge.