Lately, I've been seeing a lot of mods that are colored using the heat treatment/torching method. The results I've seen have varied greatly from spotty and poorly done to uniform, professional grade finishes. Some mods have many colors in the finish (JM 22) and some are finished in one uniform color like blue. (Nemesis)
I would like to know if anyone has any insight on the processes for how this is done as I would like to do this myself one day. I have read things like a propane torch is best and that dipping in oil can affect color, but I can't confirm those things. I think how hot an area is treated can affect color as well. Any insights on how the coloring is controlled are welcome. I would also like to know if there is anyway the finish can be sealed or protected. I have read that sometimes the coloring can rub off very easily.
If you own a heat treated mod or have heat treated some things before your contribution is much appreciated.