Nitre Blue is great stuff! I've been using it for many years. I think it bears mentioning that you have to be careful if using it on blades.....all too often I have seem beautifully blued blades, that were worthless cutting tools because the individual didn't realize that they had "over tempered" the blades with the Nitre Blue.
As long as that's kept in mind, its one of the simplest and most effective/durable methods of bluing available.
Doug! The sultan of steel! Great pic. Thanks for joining in here.
I just started playing with Nitre blue salts but I was all over the place on my temp. My deep fry thermometer pegged at 550F and I wasn't sure how accurate it was at that temp. I just got in a thermocouple with a decent K coupler so I could do a better job at hitting that temp range.
I will give that temperature range some attention and try get close to those colors.
I also have some Oxy7 on order to give those a go.
That is some good looking steel - I especially like the 3 pieces that have the bright blue. What metal is it, and if you would share, method to get that blue? Next question is how to get a blade with that since it's at 500°F plus working temp - that's well above most temper range for normal high carbon steel.