In finishing my new 40 cal rifle, I blued the barrel using Pinkerton's old time American rust blue. I have used it before on pistols, and my son welded me up a dandy boiling tank. It sits over two stove burners and will hold a barrel 48 inches long including the tang. Ok, what happened was rather odd. It takes so long to bring this big tank to a boil on a standard electric stove, I decided to do all the rusting and carding, and boil it after the rusting was completed, rather than after each carding, which I did last time. It was low humidity for almost a week before some rain came in and the rusting got going good. I carded the $#*! out of it, reapplied the solution and did this about 6 times. WHen I got finished, the barrel was already blue-black and not brown. I rubbed it down with oil 5 or 6 times, and think it has dediced to stop rusting and be blue for a while.
Why did it turn blue without boiling? I had not seen this happen before. Do I need to do something else to ensure it does not continue to rust under the oil?
Thanks.
Frog