I destroyed a board when i tried to cure it with too high temperature in the oven.
The foam sunk - a lot. Just for fun i’ll make a stepped board out of it.
Started with scalping the board to get rid of the worst parts. I used a multi-cutter to cut the shell, then peeled off the composite and used a hotwire cutter to cut the damaged foam away
Then i added a tail of xps250 foam reinforced with some layer of carbon, sanded the bottom flat and glued a 5mm 80kg/m3 pvc foam to the bottom with foaming PUR adhesive.
I have to admit i just freebased the cuts. This board will not be symmetrical anyway since it’s skewed and dimpled in all directions - it’s a choice of accepting asymmetrical surfaces or trashing it.
Next step is a light spackling to smooth the worst dimples and ridges.