Mark offers some thoughts on cracks in the tops of vintage guitars. You’ll learn why they happen, which ones are more concerning than others, how to spot them, and what to do about them.
Shop Talk
Acoustic guitar top cracks – How they happen, which ones are concerning, and what to do about them.
Bridgeplate Positioning
This kind of bridgeplate positioning is a regular sight in a 50’s Gibson.
Someone didn’t like their job all too much, I figure.
A lifetime later, these sort of idiosyncrasies are partially responsible for the tonal variation between otherwise similar Gibson flat tops.
This is a 1951 J-45 that’s on the bench for a neck reset and some requisite brace regluing.
The road to the modern Gibson flat-top…
The road to the modern Gibson flat-top acoustic began in 1926 when the L-1’s arched top was replaced with a flat, braced top. Those first flat-tops featured the familiar small and round L-body shape, a carved back, a long and narrow ebony pyramid bridge, and a unique early version of H-pattern top bracing. A year later the guitars had flat backs and the first sunbursts were being rubbed on flat tops.
By 1928, Gibson flat top designs had evolved into the L-0 shown here. The long and narrow ebony pyramid bridge was replaced with a stout, multi-layered rosewood one with interesting architecture and a 7th pin (more about these 7th pins to come). The H-bracing evolved as well, becoming slightly lighter and more flexible, with angles tweaked to improve mid-range presence, volume, and overall sweetness. The first adjustable truss-rods show up in flat tops in early 1928, and necks become a bit more comfortably rounded, narrower at the nut and more highly radiused at that same time.
It’s an interesting transition, and one that continued through 1933 when the first truly modern 14 fret steel string models are shipped from Kalamazoo.
13 fret Gibson L-00
Mark discusses the unique 1932 Gibson L-00 with 13-fret neck joint, and the specific considerations that went into its repair.
1933 Martin R-18 repair
Nightshift guitar repair going on here with a 1933 Martin R-18 on the bench – the little sibling of Martin’s C-1 archtop.
Unlike the carved C-1, the R-18 has a pressed top that is just a bit thicker than a normal flattop top and features a beefed up X flattop style X bracing, complete with a little maple bridgeplate.
It is interesting to compare this model with Gibson’s flattop guitars that featured trapeze tailpieces and archtop-style bridges at around the same time.
Both Martin and Gibson were trying out bold new ideas in the early days of steel string guitar-making in the late 20’s and early 30’s.
Three Great Vintage Small-Bodies Gibson Acoustics with Mark Stutman
1947 Gibson LG-2 repair
Some top crack repairs are more involved than others. This is the Sat-on-at-a-party-long-before-Covid 1947 LG-2. Still a long, long way off from completion, but a little bit closer now.
Nothing terribly fancy going on here, but I think it looks interesting enough to share. The top cracks are being glued while the simple wedge system is pushing everything together; the clamps and 25 lb sandbag are keeping things properly aligned. The treble-side crack was done yesterday. It follows the grain at the outside edge of the pickguard to within 2” of the top, and all the way to the bottom of the plate.