I thought I would share Oscar's method of niter blue. He was kind enough to show me how he did this on more than one occasion because I'm sure he thought I wouldn't remember how to do it otherwise.
Oscar used laboratory grade Potassium Nitrate and a very small amount of Manganese Dioxide in his niter pot and it was hot. You might ask hot is hot and all he ever said to me is "you'll know when its hot enough". I'm only guessing in excess of 700 degrees. I supose I could check the temperature with a lead termometer but I don't trust the accuracy of those gagets much at all.
I don't believe that the niter salts that Brownells sells can get to the temperature needed to get the correct color. The niter blue that I've seen from the Brownells product always has a plum cast to it, meaning it just didn't get hot enough to go through all the color phases.
Anyway here's a picture of a Fox Sterlingworth trigger guard that I did this morning to show what I think is the right color. Its a blue-black color with no plum overtones. I didn't take this to a really high polish because it is a Sterlingworth and probably wouldn't look correct otherwise.
