Note: This is a continuation of two earlier threads:
Some Thoughts on Design
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You don't need a mould to build a guitar. The traditional Spanish method, used by most of the great classical and flamenco builders of the 20th century, is to assemble the instrument freeform on a flat workboard, or "patron." The method is very thoroughly described by William Cumpiano in his useful book _Guitarmaking: Tradition and Technology_ . Here's a Cumpiano-style workboard:
The cork and paper "shim" on the top of the patron is designed to allow for the slight arch cut into the bracing of most classical soundboards.
It's a proven method, well suited to small shops with few power tools.
However there are advantages to building the instrument in an outside mould, and in recent years I've switched over to this method of construction. My main reason for adopting the outside mould is that it is better suited to the use of "spherical" doming on the back and soundboard. More on that presently.
Here's a typical outside mould (this one's for a mandolin, but the principle is the same):
I don't have a mould for the body shape I've chosen, so in this thread I'll make a new one.
I start by gluing two sheets of 3/4" ply together. On this, I trace the outline of the guitar and then use a bit of scrap wood to offset the outline by two inches:
I cut out the workboard and set it aside.