> Etched in about 10 minutes in my heated/aerated FeCL3 bath. I use HCl (pool acid) and H2O2 (concentrated 30%, not pharmacy-grade 3%), a couple tablespoons of each in a cup or so of water, no heat, no bubbling, etching takes about 3 minutes, and the bath is reusable indefinitely; just keep topping up with chemicals.