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Tutorials - Coppering Damascus
How I make my coppered damascus blades.

First of all, you have to make a copper-based solution to apply later on the metal.

1 liter of distilled water.
25 gr of copper sulfate.
20 cm3 of sulphuric acid.

You have to dissolve the copper sulfate on the water and then add the acid. Then, using a patch of fabric of a brush you just apply it to the damascus blade. Good thing is that it will (kind of) respect the finish of the blade, but with the typical redish tone of the copper.

Once it dries, you can hand polish it or even use a soft belt on it. On one blade, after the acid etch, I leave if a while on a 1:1 solution of water and clorhidric acid until the black residues of the steel with more composition of carbon disappear. Then I apply the copper solution and after that, I use a water 600 grit sandpaper to remove it from the surface of the blade, leaving only the bas-relief part of the blade covered with copper. (Picture 1)

On the other blade, the technique is easier, as I just apply the copper solution after the acid bath, so the copper adapts itself to the previous shades of the damascus, resulting in darker lines where the steel was black. After that I hand polish the blade with some fabric to get the final results. (Picture 2)

Note that both blades are made of the same damascus, and while the scans and the colors do not match exactly, you can see that the bas-relief parts of the first blade are the same color as the high-relief parts on the second one.

One thing to note about this is that the copper just bonds with carbon steels, not with stainless steels (or nickel, as I tried this process on my "coin damascus" too and it didn't work out well)

As the copper oxidizes with the carbon steel in a passive way, it prevents the steel from rusting with the oxygen.

I tested this on a carbon steel ruler I used to use to measure the forged blades on the anvil and while the non covered part got rusty, the copper covered one did not. I don't know how rust resistant it becomes, but it sure delays rust on the carbon steel.

I've been also experimenting with galvanic techniques for carbon steels and now I use an electrolytic process based on cyanides and the results are much better than the previous two other method I just described.

This is a more complex process, but more importantly, it can be very toxic, so if you're going to try this, please be very careful. Do it outside or on a very ventilated place, using gloves, as the products involved can be hazzardous for you health. On the small scale that I use, I don't really get much fumes, but still take that into consideration if you're going to do it.

For the electrolitic solution, I put a liter of destiled water on a plastic or glass recipient and then I add 30g of copper cyanide, 25g of potasium cyanide, 15g of sodium carbonate and 2g of sodium hyposulphite. (Picture 4 and 5)

I use a car battery (12V) with a charger, a variable resistance and a voltimeter (tension=2,5-3V)
You can easily make a variable resistance for this process using the wire nickel-chromium resistence of an old electric heater, serial connected to the galvanic circuit, adjusting the clamps til the voltimeter marks the desired voltage. (Picture 6)

The piece to copper gets connected to the negative and the positive goes to a copper barstock/flat barstock inserted on the solution.

As reference, for a 6" blade I leave it 20 minutes at room temperature.

Tutorials - Coppering Damascus   Tutorials - Coppering Damascus   Tutorials - Coppering Damascus   Tutorials - Coppering Damascus   Tutorials - Coppering Damascus   Tutorials - Coppering Damascus   blank image   blank image
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Finished Knives
Coppered Damascus Drop Point   Coppered Damascus Drop Point   Coppered Damascus Drop Point   Coppered Damascus Stag   Coppered Damascus Stag   Small Cable Damascus Utility   blank image   blank image
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