1. Using tape to determine the size of the gap that needs to be glued. 2. Threading the stem of
the trimmed pipette into the brace repair tool. 3. Applying Titebond glue between the top and
brace using this specialized tool. 4. The scissor jack and brace repair jack make it much easier
to hold and clamp braces. 5. Positioned inside the guitar, a single brace repair jack clamps the
upper face brace to the top. 6. The 12-string’s elongated peghead features two triangular pearloid
inlays, which look particularly cool under the yellow tint of the aged nitrocellulose lacquer.
7. What a beauty! The restored ’67 Gibson 12-string.
The B-45-12 is a 12-string dreadnought
that Gibson first introduced in 1961.
During the ’60s, such legends as Gordon
Lightfoot, Leo Kottke, and Reverend
Gary Davis made history strumming on
their B-45-12s onstage and in the studio.
Kottke liked the warm sound of the guitar’s
mahogany back and sides, and the B-45-12’s
adjustable bridge and ebony saddle made for
a very playable 12-string. In 1963, Gibson
introduced the B-45-12N, with the N indicating
a natural finish, as opposed to the
standard cherry sunburst on earlier models.
The guitar featured in this month’s column
was built in 1967 at Gibson’s factory
in Kalamazoo, Michigan. It features a Sitka
spruce top, solid mahogany sides and back,
a mahogany neck, a Brazilian rosewood fretboard
and rectangular bridge, 3-ply celluloid
top binding, and single-ply back binding.
Other appointments include a tortoise-color
pickguard, Kluson Deluxe 6-on-a-plate
tuners with white plastic buttons, and a
chrome-plated trapeze tailpiece.
This guitar’s owner thought it might
have some loose braces and brought it in
for me to inspect. If you suspect that an
acoustic guitar has loose braces—because
you’ve observed structural issues or heard
rattling noises—then every brace on the top
and back needs to be checked inch by inch.
For the initial test, I like to gently tap on
the top and back. Most of the time (but not
always), I can hear if there are loose braces
lurking inside. Even when acoustic guitars
come in for just a basic setup, I like to
thoroughly examine them. I’ll automatically
inspect the braces by peering through the
soundhole with a combo mirror and LED
light (item #3225 from stewmac.com).
Other useful tools for examining braces
include the telescoping inspection mirror
(#0362) and the folding 3-piece inspection
mirror (#5124)—a set of reflective acrylic
panels you can fold up to get through the
soundhole. Once the panels are inside the
guitar, you unfold them to create a flat 7
1/2" x 12" viewing surface. Very slick!
Earlier ’60s editions of the B-45-12 had
issues with construction. The guitar’s dainty
bracing allowed for more tonal projection, but
because they had a pin bridge, rather than a
trapeze tailpiece, early B-45-12s often pulled
apart—especially when tuned to concert pitch.
Luckily for the owner of this guitar, his
instrument had a trapeze tailpiece. Once
I inspected the braces, I found only a 1"
end section of an upper face brace that was
loose. Overall, that was a minor repair compared
to what it could have been.
I was delighted that this project gave
me an opportunity to try out a new
tool I’d just purchased from Stew-Mac.
Designed by Dan Erlewine, it’s called the
brace gluing wedge (#0200). You use this
tool to gently shim open the gap under a
loose acoustic guitar brace and inject glue
right into the gap.
Before using the brace wedge on the
B-45-12, I did a dry run and practiced
positioning the brace repair jack (#3544).
For this repair I also used a scissor jack
(#0490)—a fantastic tool that lets you
clamp areas that your arm can’t reach when
working through the soundhole.
After filling the brace wedge’s pipette with
Franklin Titebond glue (#0620) and gently
squeezing the bulb to inject the glue into the
gap, I set up a single brace jack to clamp everything
back together. The final step was to carefully
wipe up any remaining glue squeeze-out.
Once the glue had dried, I removed
the jack and strung up the Gibson
12-string. Tone is so subjective, but to
my ears, this Gibson B-45-12N has an
awesome sound with glorious sustain. It
was wonderful to get the instrument back
into top sonic condition.
John Brown is the
inventor of the Fretted/Less
bass. He owns and operates
Brown’s Guitar Factory,
a guitar manufacturing,
repair, and restoration facility
staffed by a team of talented
luthiers. His guitar-tool and accessory designs
are used by builders all over the world. Visit
brownsguitarfactory.com or email John at
info@brownsguitarfactory.com.