Nice results
I started using this as an additional option for customers to dress up their guns. Playing with the heat creates some beautiful colors. While it's not the best coating for parts that see a lot of oily hands of wear, it really adds to any project. Keeping it oiled will help with fingerprints, it does require some general maintenance to keep its look, I find it to be worth it.
Yields beautiful finish
I blued various polished steel AR-15 parts, and the bluing salts yielded a BEAUTIFUL finish that is an iridescent purple or peacock-blue. I was hoping for a lighter color blue, but it's hard to gauge the resulting color on varied types of steel: my trigger, for example, ended up more of a straw color, and other parts were a little on the lighter end. I used a jeweler's kiln to keep the salts at a very consistent 640 degrees fahrenheit (+/- 5 degrees), and I used a laser thermometer to verify the consistent temperature. I used a small baking pan that I picked up at the hardware store to hold the salts, and a tea scoop to pull the foamy pink dye off the top as the salts heated up to liquid state. Parts were suspended from aluminum bars using baling wire and a tea basket (for screws and tiny parts). I quenched them in a large metal bowl of water. I searched on the internet for color charts, which were somewhat accurate, but most sources I do believe included the need to check parts. Leaving them in longer than 10 minutes did not appear to make much difference. The included instruction manual is helpful, and this is not an exact science when working with various commodity parts having unknown metallurgical properties. That being said, I am extremely happy with the result of my finish on the parts blued, and will be using these salts in the future (with plenty leftover). I definitely recommend using a kiln if possible, as the heat is very controllable, and there were ZERO safety issues or spills or air bubbles splattering molten salts all over the place. I am not a professional gunsmith, just a hobbyist, and apart from the need to derive the exact resulting color by trial and error, this product is very easy to use. See attached images for before and after of the parts in question.