I rebuilt my vacuum jig. I used 3/4 x 3 poplar mitered into hexagons then layered up with alternating joint lines. I then rubbed in a very thin layer of silicone to improve the vacuum. The rubber is from LMI. I also realized that my epoxy painted floor would make a great base so now all I need to put my sanding dish on the floor, cover with the jig and turn on the pump. It pulls ~ -23 inches, I have the LMI bridge jig that pulls a little over -25 with my pump. Not bad considering the size difference.
