The only other method would be to powder coat it
The other method is black oxide. I gave a link to a cold kit above.
If anyone tries it I'd love to see how it turns out. I'd like a carbon steel black oxide, I just don't know how the stainless version ends up.
Gun bluing is not supposed to work on STAINLESS. Hot blue that it sounds like you're talking about part of the time is out of the scope of someone at home, gunsmiths have some pretty nice set ups to do that.
Even on small touch ups on CARBON STEEL those bottles of cold blue do a pretty crappy job sometimes and I have yet to find one that doesn't say "not for stainless" on the bottle.
Rust in that video means that wasn't STAINLESS.
Powder coating means sending it off. May as well try a flat black auto paint and bake it in the oven.