I have used Pilkington's solution and Brownells solution for rust bluing. I applied the solution at night and hung the parts up, no steaming. Boiled the parts in the morning. Or applied the solution in the morning and boiled the parts in the evening. Carded the parts after boiling and before the next application.

Boiling was done in a stainless steel tank fabricated from the top of an old deli cabinet. I tried brazing the corners of the tank I made but could not get a good seam, probably the wrong brazing material. I ended up using a good, quality epoxy cement to seal the corner seams. The tank is held in an angle iron frame I made and attached to an old propane bbq. The burner is a piece of black iron gas pipe with a bunch of hacksaw cuts for the flame points. Drilled holes i think would have been better.

The water I use is plain tap water, nothing special.

I have had no issues and spectacular results with the above method.
The work is done in my garage in Charlotte, NC.

Vlad