French luthier Benoit de Bretagne has an excellent forum discussing all aspects of guitar making.
The following description of making the 'pliage' was found many years ago.
According to Google Translate:
Selmer first folded the 2 parts, then glued them together, not easy!
(let's not forget that this fold comes from the Italian invoice of mandolins), on these Italian instruments, a fine groove could be made, then the table was folded, you can make this groove using a dremel and d 'a thin burr, to make a straight groove slide the base of the dremel against a ruler.
Place the soundboard face (rose side) against the workbench, fix a ruler and clamps together just before the groove (near the mouth), moisten the groove with hot water and bend using 'a wedge that you will slide progressively under the table (see photos).
