I have been doing a lot of water line cutting of 2/2.5D objects in brass. I have but the .500" stock on top of another piece with carpet tape and then held it in the flip jig. This works great most of the time as long as I use an end mill. If I use a ball to penetrate the bottom of the stock on the final cuts it breaks away from the tape and ruins the job. I believe due to deflection from the ball.
I would like to do more work outside of the flip jig. I have tried the blue wax but really do not understand how people are saying it is so strong. I can usually break the stock free with some force by hand. The bigger issue I have, since I have successfully used the wax, is that the stock is not level since it is resting in a bed of wax. I have heated and gotten it to a nice pool, then clamped it in an arbor press with blocks of aluminum stock. It still leaves a slightly unlevel condition. On the final cutout part, the edges are not square due to this being unlevel.
What have you found to be the best for holding .500" work?