We bought some big planks of Aluminum (big) and cut them into sets of plates. Use these as quench plates for your air hardening steels instead of air or even oil hardening steels. Tip: In use, place your knife from the oven, still in the pouch between the plates. Press flat with your hand. You don't need much pressure at all. Shoot compressed air all around in between the cracks. Your knife should be cool to the touch in just a minute or so. Tip: I've heard of some guys putting their plates in the freezer before quenching. If get condensation on the plates and then place a burning hot packet of steel in contact with the water, you are going to have a dangerous out gassing of scalding steam. Best to avoid that. Keep you plates dry. note: similar to picture