Lacking an insert plate for the 10-inch Delta bandsaw (model 28-195) at work, I made a new one out of ABS plastic using our 3D printer. Here's the result:

Rough-but-ready output from the Solidoodle

The geometry is two discs stacked on top of each other with a little bit of a cutout at the edge behind the blade, which helps prevent the insert from twisting too much. I've modeled a slot a bit larger than the kerf of the blade and included it in the printed part but you could certainly leave that off and cut the slot into the insert using the bandsaw itself, making what's called a “zero-clearance” insert.