What's the harm in this process if misrepresentation to others is not the intent? As it has been described, it seems about like using cold blue to darken a shiny area or temper a scratch on the old Elsie. This process seems like just another little method we have to accomplish a certain result on a certain gun.
I, for one, would like to see what Mike might develop with his beater Flues. It would be interesting also to learn whether starting with bright metal is preferred to starting with metal retaining some CC, whether 44/40 and Oxpro Blue yield the best results, or whether there's something else out there that might even be better, and, last, how well lacquer or some other clear coating might give the color staying power.
