Copper patina

T

Tkrocky

Joined
Sep 6, 2013
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Does anyone know how to put a real dark patina on copper? I have a few ideas but I am sure you tricky geniuses have some good tricks up your sleeves. I want to get it close to black. Any pictures would be much appreciated as well!
 
You might want to try liver of sulfur. Make sure the liver of sulfur is fresh and the metal is absolutely clean; no films of oils, finger prints, cleanser residues, etc.
 
I use liver of sulfur for making copper almost black. Looks like ancient Japanese shakudo/shibuichi.

Once all work, engraving, polishing, etc. is done on the copper piece, I clean the metal by washing in hot soapy water, then scrub with 0000 steel wool. Next, I wash again, and immediately place in freshly mixed liver of sulfur. I put about a ounce of the molasses like liquid/gel in a cup of warm water( It also comes as a powder, but the gel/liquid is much better.). Let the copper soak for about two minutes, take out and rub with the steel wool, wash, and soak again. Extend the soak times to 5, 10, 15, and even 20 minutes as needed to get the desired results. Once the surface it well patinated to the degree you want, wash well, dry completely, and buff with steel wool. All that is left is to assemble the copper part on the knife.
 
^If you try ferric keep it set aside... the copper/ferric solution will copper plate steel.

Grobet makes a liver of sulfer gel that works great, is easy to use and stores well. It blackens copper and silver nicely.
 
The Japanese have a long list of coloring agents for various copper alloys .You'll find them on the internet.
 
With several long soaks, the patina is quite rugged. It forms a surface layer of hard copper sulfate. I can buff the pieces on my buffer and iust just gets shiny.
 
You can also apply a heat patina to get a mottled black finish that is pretty durable. Flame your piece until reddish orange and allow to air cool. Then you can buff lightly or rub with very fine steel wool. If you want a consistent finish, the liver of sulfur as mentioned is better.

Brett
 
Reactive metals sell a pre-made patina that does a great job.

ferric will not darken copper it just dissolves it. ferric was originally used to etch the copper off of circuit boards.
 
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The online knife supply houses have something called "Brass black" in a little bottle. (Jantz, etc)
It's probably L. of S., who knows, but it comes in a small bottle ready mixed and works.
 
If you just want a little black in the background of some engraving, or a surface black color, those Wipe-on...Wipe-off things are OK, but they will rub of with very little wear. If you want to chemically change the surface of the copper to a harder and more wear resistant silvery black ...use Liver of Sulfur. In a very simplified way, what you have done is coat the surface with niello like metal.
 
Strigamort said:
That sounds interesting. Could you plate a ht'ed blade to achieve a different look, yet maintain a suitable hardened edge? If so, why does no one do this?
Click to expand...

I've done this in the past to achieve a sort of "antique" finish.

It didn't plate the blade, but did result in interesting copper accents on the steel.

A quick soak will not damage the edge.
 
Simple google search came up with:
The Science Company has collected these recipes from a variety of sources through the years. The formulas have not been personally tested so there is no guarantee that they will work. We suggest they be employed on a "trial and error" basis first so their effectiveness can be judged by the user.
Linkee:
 
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