How many cycles are you running your test pieces? The black builds slowly, on fluid steel it take typically six or so cycles before the black really deepens. You steel wool degreasing is fine, I rotate the pieces in the soak, so whatever piece I take out has been in at least 24 hours.
I let solutions set for a day or two after making them, with occasional agitation. It's not as important if all the ingredients are liquids. Using dry ingredients like copper or ferrous sulphates is a little different.
Are you using distilled water for your solutions? City and well water can both contain chemicals that can alter solutions, mainly calcium and carbon compounds, which can mess with the acidity of the solution.
Regards
Ken
Last edited by Ken61; 03/18/17 11:52 AM.
