I have not done any bluing in some time now. I have tried both the cold rust & Hot rust & much prefer the cold method. I think I bought one bottle of Pilkington's once & found it very good, but pricey. I have also tried Laurel Mountain. It was sold as a browner, but the simple act of boiling it in hot water after the rust converts it to the blue (Black). It was not quite as fine-grained as the Pilkington, but perhaps if it was diluted to a weaker solution this would be remedied, as it was more aggressive. Most of my rust bluing was done with homebrews with recipe taken from Angier's book, though I'm not sure now which one I settled on. I tried to avoid those with mercury, even though this addition makes for a very effective blue. Have recently read of using a mixture of Hydrogen Peroxide, Vinegar & Salt but have no experience with this.
I did note that Brownell's now lists a solution under their own name which sells for the same quantity as the Pilkington for around $10.00. They call it a "Classic" blue I believe, may be very similar to the Pilkington. Could be worth looking into.
