Thread: birchwood cold bluing turning to rust one week later

Originally Posted by gundoc

Not only is rinsing with hot water needed to neutralize the residue after allowing to dry and carding with wire wool or 3M pad, but warming the part with boiling water before blueing helps get a deeper finish. The secret is absolute cleanliness of the metal before application of the solution. I use acetone to degrease and allow the boiling water rinse to evaporate before applying the blue with a cotton bud. A perfect match is difficult to achieve and large areas were never intended for the blue, just touch-ups on small areas, screw heads etc.

Interesting, I was told to do it with cold water, anyway, I will give it another go and perhaps get some acetone to give it a good rub down.
I wonder if there was still a bit of oil on the barrel perhaps?