Nunome Zogan


I stumbled across a description of 'nunome zogan', a Japanese inlay (or, I guess, on-lay) technique. A hard metal - iron or steel, usually - is given a file-like texture with a chisel, and a soft metal (silver or gold) is hammered into it. After burnishing and planishing, the soft metal is permanently attached. The iron is usually patinated to give a strong contrast.

I made a tiny chisel, got a bit of mild steel, and had a go. The sequence was:

Shape the steel, and clean up with wet & dry.

Apply the chisel pattern in two directions.

Get distracted, and use a curved chisel to do some scalloped textures.

Cut up bits of 0.1mm fine silver sheet.

Punch them down with a bamboo punch (made from a chopstick)

Burnish silver and steel with a hard steel burnisher.

Planish with a small round punch, to texture the silver and smooth out the steel a bit.

Etch in ferric chloride to matt the surface.

An unsuccessful excusion into rust-browning, subsequently cleaned off.

Heat-blue the steel.

Wax with Black Bison furniture wax.

And here's another experiment:

Shape the steel, and clean up with wet & dry.

Chisel as before, and apply fine silver shapes cut with paper punches.

Burnish and planish.

Clean with detergent then acetone.

Brief etch with ferric chloride, just to matt the surface.

Rust using (I think) this peroxide recipe

Wax with Black Bison as before.

The blackening wasn't entirely even. I suspect I should have done the rusting process for a lot longer. I could also have boiled it in tea for more blackness.

Here's the recipe in case the link goes bad (thanks, Henrik!):
2 parts Hydrogen peroxide
1 part Vinegar
Table salt
First you take the Hydrogenperoxide and heat it in a microwave oven and then add as much salt that can be dissolved and then the vinegar.
Take the iron piece and warm it with tap water and then apply the solution with a paintbrush. It starts bubble and make a white foam. Rub it with the brush 20-30s and then rinse in warm water. Repeat about 10-15 times until you have an even layer of rust. Now it will be brown and to make it black I boil it in water for about 30-45 minutes. I add a little tea, some say it won't be necessary but I imagine that it helps to color the surface.
If you don't want it black then boil it for less time, take it up and check it continuously until you are satisfied. Then wax it to get a little more glossy look or oil it to keep it dull.

Here's a tutorial by someone who is good at it, with many pictures in the accompanying photo album.

And here is another summary of the technique, including many refinements I have completely ignored. Click on 'Production' to see the good stuff.

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