blackening steel after inlay

[Ed Steinkirchner]

I've seen many hot and cold bluing/blackening formulas, but all that I tried have not worked out.
Well i guess my question is, what blackens steel without tarnishing/discoloring copper, brass, nickel silver, or aluminum. I ask because, short of letting it blacken with age, i cant get iron to blacken without changing the color of the inlayed wire. I've tried cold bluing but that does not work, i have tried tannic acid, and though it blackened the steel, is sanded off too easy. The spray with diluted acid, let rust, brush, and boil method is the only one that has shown any promise so far.
I've seen it done,I just do not know HOW its done.
Any help is greatly appreciated.

Ed Steinkirchner

[son_of_bluegrass]

First let me state I've never tried and may not have any idea what I'm talking about. But my first thought may be putting some sort of resist over what you don't want to change. Or maybe, depending on what you're doing, adding the inlay after cold (or hot) bluing?
Hopefully someone will come along with experience soon.

ron

[Steve Sells]

many times nickel is used to resist the bluing. Not sure about the other metals.

[tsterling]

I use Birchwood Casy Super Blue - it will color copper and brass, but then I use steel wool to bring back the shiny soft metal. Steel wool won't remove bluing from the steel but will remove the patina from copper and brass - don't know about aluminum. Of course, the brass or copper will darken with age and use anyway, if you want really long life fine silver and high carat gold are your only real options.

[MattBower]

The spray with diluted acid, let rust, brush, and boil method is the only one that has shown any promise so far.

Most of the acids folks use for that purpose will react with things like copper and silver, so proceed with caution. (I normally use salt and hydrogen peroxide for rust bluing, but peroxide is hard on silver, too.)

As for how to do it, you just described it! It's not complicated. It just takes patience. Distilled water and very thorough degreasing are also good ideas.

[Ed Steinkirchner]

How is the hydrogen peroxide and salt used? The only method using peroxide i know of involves immersing iron in heated peroxide and salt, cleaning off the rust, and repeating. I've never done it, but will probably try it anyway. Tarnishing/ damaging silver wont be an issue, because I cant afford it! But ive already got a list of a few things to try when I can get to the shop.
Thanks for the help so far.

Ed Steinkirchner

[MattBower]

How is the hydrogen peroxide and salt used? The only method using peroxide i know of involves immersing iron in heated peroxide and salt, cleaning off the rust, and repeating.

That's the one. Nothing magical about it. Heat the peroxide to near boiling (just makes it work that much faster) and add salt until it doesn't want to dissolve anymore. Then dip, card, dip, card, ad nauseum, and boil. It just takes patience. I've tried spraying on the peroxide and salt solution, but I think immersion works better. Some people say to add vinegar. I've found it to be counterproductive.

Another method of doing the same thing, but building up the rust much faster, is to apply cold gun bluing to the steel, then apply -- dip, wipe, or spray on -- chlorine bleach. It'll rust like mad before your very eyes. (Play with it to see what works best for you, as far as keeping it submerged, removing it from the bleach, wiping it on, etc.) I learned about using bleach and cold blue to cause rust from guys who use it to give a really aggressive etch/patina to age steel, but it occurred to me that you could also card the rust and continue the process, then boil to convert to black oxide. And sure enough, it works. (I like to change the water a couple times to be sure all the chlorine is gone.) That should serve as a word of warning: it'd be easy for this to get out of hand. It is shockingly aggressive. (See here: http://www.bladeforums.com/forums/showthread.php/632510-Bluing-and-Bleach?p=6652243#post6652243) This tends to give a fairly thick, kind of rough oxide layer. I consider it kind of crude compared to peroxide and salt, but it works and it's fast. I don't know what it'd do to silver, brass or copper, but I wouldn't be surprised if it was pretty harsh.

[Ed Steinkirchner]

That looks like the process i need then. Looking at the link, I saw a tomahawk with brass inlay and that seems to be the technique to work with. One way or another, I'll make something work, but I think the peroxide and salt method is what i'll go with. Thanks for all the help so far everyone, though I won't be able to try anything until the weekend or later. Classes and all that really get in the way some times but, oh well.
I will post pics of the results eventually.

Ed Steinkirchner