[TheForge] Black oxide finish

[Andy Vida]

"Robert B. Miller" wrote:
> 
> Hi, Folks:
> I am new to the list (this is my first post) although I have I have read Ron Reil's accumulation as well as a few in the archives. I am making a door knocker that needs to match a mass-manufactured door pull with a flat black oxide finish. I have found some commercial products for a cold oxide finish (I want to stay away from the hot oxide) but most systems are much more money than I want to spend on a $100 door knocker. Can anybody offer some advice on how to get a good flat black oxide finish cheaply? It has to be something that won't rub off, and applied after pickling to get the scale off.

	Heat's pretty much it, just less of it.  Pickle, if you must,
	then neutralize.  Hit the work with a torch, or toss it into
	the forge just until it turns black.  You will be at perhaps
	800*F. Remove, let cool to about 400* and take a rag that is
	well dampened but no soaked with linseed oil.  Apply a thin
	coat of the oil to the work.  It will smoke, which is a good
	thing as the oil will polymerize in the heat.  Don't let the
	work be too hot or it won't come out as well.  Don't soak it
	too much or it will not fully polymerize, leaving it either
	wet or tacky when cold.

	When you have it right, the piece should be mostly "dry" and
	will have a slight gloss.  The color should be a nice deep
	black.  I would not go too nuts-0 about trying to get a
	Pantone match for color.  As you said, it's a $100 door knocker
	and for that money one cannot reasonably expect too much.

	Let it set over night and by morning the surface should be
	completely set up.  It is a great finish and even outside it
	would last if the doorway is protected from direct exposure
	to rain.

	You can use cold blues, but that will take a lot of time and
	effort.  I have used Winchester cold blue, which produces a
	beautiful blue black, but it is a pain in the ass to do it,
	what with perfectly clean surfaces, applying the blue, boiling
	the piece to force the color reaction to take place...  I would
	not do it for that money.   I guess the other thing you can do
	is take it to a shop that does hot bluing and see if they can
	match a color... not sure what they would charge, but I'd be
	almost willing to bet it would be too much, especially if there
	is any sort of special setup.

	Use heat. :)

	Best wishes.

	-Andy