after 14 yrs being away from knife making .. and now going back to it ,, i find myself at a loss of memory .. harding 5160 with a propaine forge .. and using chevron 70 quenching oil . i started .. my forge at 10 lbs ,, after warming took it to 5lbs gas .. the forge is a venturi system , no blower , oil 125 degrees , my edge thinkness is 5/32nd thick enough meat to protect the inturnal egde . i have taken to nonmagnetic .. to different temps but all has been non magnetic , and after quenching .. im not getting a heavy scale at all .. and no slate gray ,, a file will cut it .. i have treated the same blades .. 3 times ,, and still the same . my flame at the ovens pipe entrance is blue , so any thoughts .. i was thinking clay coating the blades ,, to retain the carbon any thoughts ... thankyou