How acoustic guitars are made

A guitar's thin spruce top is a speaker. Braces glued inside it hold up string tension and decide how it sounds.

stations: 8
things upstream: 54
raw sources: 16
steps from the ground: 8

The short version

An acoustic guitar is a wooden box. Thin spruce is glued into a top, braced inside, and joined to bent side walls and a back. A neck with metal frets is fitted, the body is finished, and a bridge, tuners and strings are added. The strings' vibration drives the top, and the box makes it loud.

Season the tonewood

Spruce for the top, and other woods for the back, sides and neck, are dried until stable. A luthier chooses wood by how it carries sound.

Goes in
Timber
Join the top and back

Two thin boards are matched edge to edge and glued to make each wide plate. Then the top gets its sound hole.

Goes in
Adhesive
Glue braces inside the top

A pattern of wood braces is glued under the top to resist the pull of the strings. Fan bracing, used by the Spanish maker Antonio Torres Jurado, first appeared on guitars in the late 18th century.

Goes in
Adhesive
Bend the sides

Thin side strips are heated and bent around a form to the guitar's waisted outline.
Close the box

Sides, top and back are glued together around internal blocks and edge strips, forming the sound box.

Goes in
Adhesive
Shape the neck and set frets

The neck is carved, a fingerboard is added, and metal fret wire is pressed into slots at precise spacing. A truss rod keeps the neck straight.
Spray the finish

Thin layers of lacquer or varnish are sprayed on and polished. The body must stay free to vibrate, so makers keep the finish thin.

Goes in
Lacquer
Fit bridge, tuners and strings

The bridge is glued to the top, tuning machines go on the headstock, and strings are tensioned. Strings are steel or nylon.

Goes in
Steel wire Nylon

End of the lineAcoustic guitar

Worth repeating

The C.F. Martin company introduced steel strings and a bigger top, and its large dreadnought body is linked to greater volume.
No sound is amplified by an acoustic guitar. The top just moves air more easily than a string can.
The Adamas model replaced the single sound hole with 22 small ones.