gun blue to blacken copper?

[Knifemaker87]

i am wanting to make the furniture for my new tanto (check out the "hamon etching" thread for pics)
what i was wondering is, can i use gun blue to blacken the steel tsuba, and use either brass or steel blacking to darken the copper saya furniture?
will this work okay?
what is the best thing to use to blacken copper?
thanks
~chris

 

[scottickes]

i am wanting to make the furniture for my new tanto (check out the "hamon etching" thread for pics)
what i was wondering is, can i use gun blue to blacken the steel tsuba, and use either brass or steel blacking to darken the copper saya furniture?
will this work okay?
what is the best thing to use to blacken copper?
thanks
~chris

I blacken copper and brass all the time with cold gun blue. It takes on a "rainbow" effect if you stop it and neutralize it early enough. If you don't like it, it's easy enough to clean up and reblue it. If you let it go all the way out, it turns a dark black. I like the slightly aged look you get when you stop it earlier instead of the black look, so I don't have any that went all the way to black, except by mistake. I didn't take pictures of those, but instead cleaned them up and reblued them. The one thing to be vigilante about is to polish your material to at least 800 grit or finer. Any little scratch will show up much better after you cold blue it! I also clean them with acetone before bluing them. If the surface isn't perfectly clean and oil free it will make for a spotty appearance. I use a clean Q-tip soaked with cold blue to apply it to my bolsters. I mask off the knife steel to protect it.

Here's some pictures of what I've done. The three closeups were blued to different darknesses. One of them even has a "rainbow" look to it that for some reason doesn't show well in the picture. There are two full knives, one blued and one not blued for your comparison. You can see how one has a clean crisp appearance, compared to the aged appearance of the other and the aged appearance of the close up pictures.

Since I don't know what material a steel tsuba is, I don't know how to answer that question. I can tell you that the full knife with only a front bolster below and the close up of that same knife is W2 steel that was cold blued. It's also jeweled first before I cold blued it. It is definitely BLACK!