I have been using custom one-time-use vacuum pods for some time to machine bowls and trays where the raw material is barely larger than the final product. So far, I used adhesive foam strips for sealing which works but is a bit cumbersome to apply.

This time I tried using thin non-skid shelf liner (also sold as non-skid rug underlay). It is non-adhesive and just cut roughly to shape. While normally rather porous, it compresses and seals under vacuum load very well. I guess that is what I will normally use in the future when the gaps are less than maybe 0.04". Beyond that the foam strips are still required.

Note, the pics are simulated on the pod with the final finished part (it is a small rectangular olive tray made from Canary Wood). But I forgot to take pictures while machining...
This would actually be a nice method for series production. Unfortunately, I don't do series production.

This is the vac pod (without and with the sealing layer) made from scrap pine board.


Bottom side and top side (like when it was machined):