Mark graduated the Italian Spruce top today. The process starts on his ‘graduation board’. Layers of tape build up areas on the board where he wants the top to be thinner.
He places the top face down on the graduation board, and runs it through his sander.
After each pass through the sander, Mark checks the Chladni modes. The process is repeated until he gets numbers that he likes.
These are the final modes for the unbraced top plate.
This is the graduation map of the top after the initial graduations are sanded and scraped in. The top is thickest between the bridge location and the sound hole and thinnest near the end block.