This week began a long awaited project for me. I finally have the skills and knowledge to repair and re build my first guitar. The instrument is has been in my family over 40 years. It was bought by my mother from a green stamp catalog issued by her local grocer in the mid 1960's. Grocers and other stores rewarded customer loyalty by issuing stamps in a book for purchases ( much like a punch card at a coffee house ) and offered a catalog of items that could be purchased using the stamps as credits. My mother helped with all of the shopping for her brothers, sisters, and my great grandmother, so she saved the stamps and bought a guitar to learn folk tunes.
The guitar was passed to me when I was 9 years old and expressed my interest in learning to play, most likely due to inspiration from my mother's sister Trisha, who played guitar and sang to me often when I was young. The guitar is the standard department store acoustic guitar of the time; birch construction, ladder braced, non adjustable steel reinforced neck, with brass frets, nickel tail piece, cherry burst finish, and painted on white bindings and stars.
Over the years the guitar has gone with me everywhere, with and without cases to protect it. Its been banged around and left in trunks and is well used. It was designed for light nylon folk strings which I replaced at some point, on bad judgement, with steel strings which damaged the wooden bridge. Years of being exposed to temperature and moisture changes have caused the body to shrink and crack, braces to come loose, and the top to separate from the sides along one edge. The over tension of the steel strings has also pulled the neck out of alignment, which happens over time with most guitars, and causes the need for a neck re set.
The Five Star with its two loose back braces
Cracked sides from expanding and shrinking with moisture loss
Top/side edge joint opened due to temperature and moisture changes
Loose top leading to crack in side
Back slightly separating from sides on neck end
Maple bridge painted black, chewed up by steel strings
Inside view where back braces were and need to be re glued
Slightly damaged back bracing
In a repair shop this would be an expensive restoration project that would most likely not be undertaken because the cost would greatly outweigh the value of the guitar. However to me this guitar is priceless because of its sentimental family ties, and I hope to someday pass it to any children I may have along with my first custom guitar builds as heirlooms. Over the coming weeks the guitar will receive all the needed crack and structural repairs including re-gluing the top back and bracing, replacing the bridge, re setting the neck angle, re fretting the fingerboard, and a heavy cleaning and reconditioning. All while preserving the original details and vintage look and feel that comes with 40 years of play. When its finished it will hopefully look like its good old self but play better than the day it was new, and be ready for another 50 years!
The first step in this process was to steam off the neck to prepare for the body repairs and neck re set. This is accomplished with a combination of heating from the outside and applying steam to the inside of the dovetail neck joint, to soften the old glue.
First the fingerboard extension over the body is heated with a hot iron and a pallet knife is worked carefully between the extension and the top. When doing this it is important not to rush and let the heat do the work. Otherwise you risk tearing the top wood out with the neck.
The iron heating the fingerboard and a shot of the old brass frets. The 13th fret is removed and a small hole is drilled through the fret slot into the dovetail joint to facilitate steaming out of the glue joint.
As the board heats up the glue underneath softens and a thin separating knife can be gently worked in between the fingerboard and top wood. After a few sessions of heat and working the knife the entire extension is loos of the top and the knife keeps it from re gluing itself.
A modified espresso machine with a section of radiator hose attached to the steam port, and a blunted large hypodermic, or basketball needle clamped to the other end , is used to pump steam into the neck joint through the small hole through the fingerboard while pressure is placed on the neck heel by clamps pressing it out using the work bench as counter pressure.
After a few minutes if all goes well the neck pops loose from its joint and all is well. The fingerboard extension should be clamped flat to a backer as it dries to avoid cupping or warping, and the soft wet glue in the joint should be removed before it hardens.
A very clean removal overall with no tearing of the top or neck and no finish damage.
I began drawing my acoustic guitar build for next semester in 3D this week using the CAD program.
This allows us to see the bracing and structural elements in 3D before we make the items. so that if there are any problems we can address them in the blueprint before the build begins.
The Mandolin build is also moving right along with the installation of the top kerfed linings, and the graduation of the inside of the top arch.
The inside edges of the corner blocks protrude into the center a bit and must be cut back flush with the ribs for a good fit for the kerfing.
After cutting the blocks back with a chisel they are sanded smooth to the ribs.
The kerfing is bent and glued into the inside edge of the rib structure, and held in place by clothes pins with rubber bands around them so that they squeeze the kerfing tightly into place.
After a few hours of clamping the pins come off and the kerfing is ready to be sanded flush with the ribs and blocks later.
Then I turned my attention to carving out the inside of the top arch. Called graduating this step gives the arching top consistent thicknesses across its curve. The inside of the top is drilled with a pattern of holes set to exact depths, then the wood is carved out to the bottoms of the holes. The thickness in the different areas is set by the depth the holes are drilled to.
The holes are drilled on a drill press with an adjustable drill stop and an adjustable guide beneath the top, This allows for precise thicknesses between the guide and the drill to be set and maintained while drilling.
The holes are deeper in the center and shallow towards the edges because the other side is already craved to its final arch.
The inside is then dished away with a gouge and finger planes until the holes are no longer visible. This creates the inside arch and brings the top to its needed thickness.
A card stock template is used to draw curves on the inside arches.
These curves are used to ensure thickness measurements (taken with thickness calipers in mm) are taken in the same places each time to ensure consistency.
Once the holes are no longer visible and the thicknesses are consistent around the curves, all that's left is to lightly scrape and sand the surface to smooth it and remove any imperfections. After i do this the top will be ready for F-holes and then it will be glued to the ribs!
That's all for this week folks! Keep checking in each week to see the acoustic restoration and mando coming together!
Oh yeah, HAPPY HALLOWEEN!