Also, from what I've read, keeping the medium in close contact with the part is essential for good color coverage. The way the parts hit the quench is also important. The Marlin Forum thread shows extensive use of racks in some of the posts, with very nice results. On another site, I read where some students at a Gunsmithing school were wrapping parts with wire with good results as well. I'm going to be experimenting with those aspects, as well as with specific shielding to see what happens. One thing is certain, the Midway video that shows the parts and medium dropping loosely into the quench doesn't result in good color coverage.
