I've used an old Chinese secret recipe for forcing patina on blades. It’s called "French's Yellow Mustard".
Ha Ha!! That’s it. No mixture of any kind. Just straight yellow mustard. For a pattern I just apply with my fingers.
Any place the mustard is the thinnest, the darker the patina will appear. I think it has to do with the way the vinegar and oxygen react with the steel, but I’m no chemist. Just my observation.
After applying the mustard evenly over the blade, I drag my fingers across the face of the blade creating thinner streaks, These streaks will be the dark parts of the patina. Just let it sit in the open air for 20 minutes or so then rinse. The great thing about it, if you don’t like it, just take a brillo pad to it and buff out the patina and begin again. Once I get the finish I like, I’ll wipe it down and apply a thin film of gun oil over the blade to keep from rusting, and it also seems to bring a little more character out of the patina. I’ll post some pics of the process when I get ready to patina this Eskabar again.
