Going back in to the far reaches of my memory to a time when looking back now at old photographs of myself, and thinking was I ever that young. The rather old man, well he was to me in my early twenties who earned a living as a Birmingham barrel finisher and told me about the "all muck and magic" of barrel bluing and browning. His continuous mantra was "the slower the rust" forms the smaller and finer its grain structure the better and longer lasting the finished job will be.
I never put forward the speed argument, just thought better of it. Though I do like the Idea of a set of shotgun barrel wind chimes in my garden!!