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Jim Kelso

Red copper patina

16 posts in this topic

I might have posted this info here before, I'm not sure. At any rate, I've consolidated information on obtaining a rich red patina on copper using a variation of my use of the traditional Japanese alloy patina utilizing rokusho.

 

The new tutorial is HERE

 

The original Japanese alloy patina tutorial is HERE

 

I would love to see results of anyone using these techniques.

 

Jim

 

IMGP1712PSE copy.jpg

Edited by Jim Kelso

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Thanks for the information.

Is it a rolling boil for 10 hrs or a simmer?

Presumably you're topping up the water over the time but do you add rokusho and copper sulphate throughout the boil as well?

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just to add, Ive gotten a reddish patina from soaking in vinegar overnight just after annealing. this is how I make my roses colored as they are.. they can be left to soak longer and you will get a more purpley red

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Thanks very much Dick. The light color is 18k gold that has been fused on. It is unaffected by the patina process.

 

Thanks Lee. I was told by Toshimasa to keep it at a low boil, and that when adding water it should be hot enough to maintain the boil. I don’t fret too much if it simmers for a bit, but I like to maintain the low boil. A big roll is not necessary. It may be that good results could come with a simmer, but I’ve never tried it. It would be worth a try, but the technique is so touchy that I try to stick with what I know works.

 

It’s usually not necessary to add additional chemicals. Sometimes I do, when moved by the devas…..

But just a pinch.

 

Thanks Pat. That's a good tip if you're using copper only, not combined in a piece with shibuichi, shakudo, etc.

 

Jim

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Thanks, Jim. I will like to share my own experience in trying to achieve the same results albeit unsuccessfully.

 

IMG_8078.jpg

 

From left to right:

1.- heat and quench in borax alone.

2.- heat and borax with a dip in rokusho afterwards.

3.- rokusho mix with borax for 5 hours.

4.- plain rokusho for 10 hours.

 

I tried the same process with the rokusho using the extended exposure time to try to go from orange to red with no success. The addition of borax was based on noticing that pickling copper after annealing can turn it red. Probably a similar process as described by Pat. The problem being, as you describe, that some Japanese tsuba display inlays of multiple alloys apparently all patinated equally (no resist-based technique) and one of the metal bits has a very deep red color, the other alloys look like they would, if patinated by rokusho. I was only able to create the deep red I was after introducing heat in the process and it was not a uniform red. I don't think that's what was used to make those tsuba. The conclusion I came to was that the "copper" may be a different alloy or as you point out "pure copper." At that point I was frustrated enough by the lack of results that I did not pursue a test plate using pure copper alongside the copper that I had been using for the experiments thus far.

 

Do you feel that the difference comes from the copper composition itself?

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Thanks Jesus. Yes, that’s the problem I had with the heat induced technique: a very uneven and unpredictable result and basically impossible to achieve in concert with the other alloys, shibuichi, shakudo, etc. as they would oxidize with the heat. I was certain in looking at works from the past such as the Shoami Katsuyoshi kogo that there was not masking going on.

 

I’m not sure what to say as my test results proved out and also subsequently in the “real” world with the little fern bit. The photo below shows the color difference with the red fern and the more conventionally colored (shorter time) Beech seed on top which is more of a nutty brown.

 

The transition time from brown to red with both the test piece and the fern in two separate baths was at about 8 hours, so very consistent.

 

Your piece on the right looks a little yellow and I wonder if you did not get off to a good start with it, which would affect the later patina.

 

The use of borax or other amendments I suppose may be worth trying, but I am holding to my theory, which has worked for me, that the extended time is the key. It worked on both the 110 alloy and a piece of unknown, but no-doubt reasonably pure copper, which essentially produced the same color.

 

I thought also years ago that some unique copper must be the key, but I don’t believe that now and my tests seem to bear it out.

IMGP1765.jpg

Edited by Jim Kelso

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That's a lovely piece. Very clever implementation for the handle.

 

Thank you for your input. I should try again at some point.

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Thanks Jesus.

 

I'm encouraging you to keep at it. About 15-20% of the time I have to back up to the polish because for some reason there is yellowing or some other problem in the patina bath. It makes sense to get the process down with copper where you can get consistent results, and then move on to the longer bath for the red.

 

One only has to look at your results in other demanding processes to know you could nail it.

 

Jim

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Another thought I had apropos of this was that both the test pieces and the fern pieces went through essentially the same color developing sequence: 1) terracotta, 2) nut brown and then the red kicking in at about 8 hours. I would guess that if you're not pretty clearly getting the two earlier colors, the red may not develop.

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Jim,

 

I did several experiments going to the 10 hour mark. I kept the solution at a simmer and added water (room temperature) from time to time. I varied the preparation of the pieces before hand thinking that there may be changes related to that. Two experiments were done starting from a polished surface that was grease-free and abraded with pumice. Then the daikon bath followed by the niage. The copper turned orange in the first 30 minutes and as time went by it became a deeper orange. Maybe even brown. I am showing two additional pieces in the picture below. One showed some hits of red but not consistent and the other looks like a dark purple. May be my preparation of the pieces wasn't as consistent as I thought. The third piece in the picture (L-shaped) is from the previous experiments. I left that piece oxidized un-waxed over the last few months to see what would happen to the patina. Sorry about the bad colors in the picture. Not much natural light left for today.

 

IMG_9866.JPG

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Jesus, it’s a scrupulous process, but quite reliable once you get it down. In some regard there is some wiggle room, but other things have to be exact, in my experience.

 

Some check points:

 

1. copper pot?

2. distilled water?

3. fresh solution?

4. I clean with lacquer thinner and then detergent then a little baking soda. Carry in a tissue

5. 2 minutes in Daikon

6. rinse pot close by. The piece must not be allowed to air dry quickly if you’re checking the color. It's ok to remove the piece from the bath, but it must be immersed in a rinse bath immediately before air-drying.

7. if you get a yellow color soon, something is wrong and you have to re-clean

8. the piece shouldn’t lay on the bottom of the pan. Better if it’s held vertically. I use a small basket made from copper screen, which itself must be de-greased. All utensils must be clean, clean,clean

 

Also you said you’re adding room temp. water. I always add hot water (near or boiling) to keep the temp up.

 

The dark color stumps me! :blink:

 

The big piece is promising with red hints, but looks like it was maybe laying flat in the pan.

 

gambate!

 

Jim

Edited by Jim Kelso

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Jesus, it’s a scrupulous process, but quite reliable once you get it down. In some regard there is some wiggle room, but other things have to be exact, in my experience.

 

Some check points:

 

1. copper pot? yes

2. distilled water? yes

3. fresh solution? yes

4. I clean with lacquer thinner and then detergent then a little baking soda. Carry in a tissue different method but I think equivalent results

5. 2 minutes in Daikon I was doing more like 10-15 minutes

6. rinse pot close by. The piece must not be allowed to air dry quickly if you’re checking the color. It's ok to remove the piece from the bath, but it must be immersed in a rinse bath immediately before air-drying. this could be the problem. I often take the piece out to look at the colors and sometimes it dries up

7. if you get a yellow color soon, something is wrong and you have to re-clean not sure here

8. the piece shouldn’t lay on the bottom of the pan. Better if it’s held vertically. I use a small basket made from copper screen, which itself must be de-greased. All utensils must be clean, clean,clean I rest the piece horizontally on copper wire, I may need to change to vertical but the pot is not deep enough for that, time to find a new copper pot

 

Also you said you’re adding room temp. water. I always add hot water (near or boiling) to keep the temp up. this could be an issue too, I will need to change it

 

The dark color stumps me! :blink: forgot to mention that this piece was flame heated before the procedure

 

The big piece is promising with red hints, but looks like it was maybe laying flat in the pan. it was indeed

 

gambate!

 

Jim

 

Thank you again, Jim. When it gets warmer I need to run some new tests implementing your recommendations.

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I think that for a relatively short bath(under an hour) the horizontal position is maybe ok. In a longer soak, the chemicals tend to rest on the piece giving irregularities. Even in a short bath I tend to shake the chemicals off and keep the piece angled in the screen holder. I stick around like a mother-hen. This is less practical on a longer soak, so I think some vertical arrangement is pretty much necessary.

 

It seems ok to interrupt the process, but it's a definite no-no to have the piece quickly air dry when still hot. Let it cool down in a rinse bath. I usually pat with a little baking soda and rinse thoroughly before re-immersion. Always holding in tissue. Body oils are death.

 

I've gathered and made an assortment of copper pots. You could also try boiling in pyrex or similar glass-ware. I've never tried it but think it probably would work. Definitely not in a "stainless" pot.

 

I think you're on to it Jesus. Just need a couple of refinements.

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