"Back to my marine/awning shop and they made them with hems on the long sides with grommets every 12 inches. Bungie cords hooked through the grommets kept the canvas tight and made a great working surface."
Now that's a great idea. I've constantly been trying to find a way to secure my canvases to the tables. I thought about using C-clamps, but those would be in the way. The bungie idea is great, though the canvases I have, don't have grommets. I supposed I could add some???
A simple method is to use picnic table clamps.
Even better. Thank you Sir!
For future reference, some put screws or bolts, or even nails close into the sides of the table to hook the grommets onto. Canvas is then easy on and off.