[Unclenick]

My experience matches the last two posts. I think the blotching problem with Dicropan IM has to do with the steel alloy. It seems to do much better with some than with others. When you are done, though, you've got a fancy version of a cold blue that will not wear as well as real rust blue.

Rust blue is the cat's meow for appearance. Because the super fine surface rust microscopically pits the surface, it is not a high polish blue, but rather has a very slightly satin sheen. It is bluer than, say, S&W hot bluing which, I believe, has some nickel or other additive salts to make it blacker. Rust blue is the classic custom shotgun finish.

Getting the wire brush is the way to go if you have a buffer. But if you are just doing one gun, you can degrease 000 steel wool by soaking it in a couple or three rinses of virgin mineral spirits, and use that for carding. I strongly recommend you do your boiling in distilled water. I've had the experience of very hard water pH preventing the conversion from succeeding, and you still need distilled to prevent water spots. So I just buy enough distilled water at the big box store to use fresh distilled water for each boil. It always works.

The Pilkington solution works well, but is expensive. The Mark Lee solution is much less expensive and was written up as successful in American Gunsmith awhile back. It was out of stock last time I tried to get some to try, so I can't say anything from personal experience with it. If you have the time and patience and access to nitric acid, you could also make an old fashioned steam box, but that always seems like too much trouble to me.