Water and some spoons of instant coffee. It is a very slow etching. You can put a blade in for some hours without a big risk to remove too much steel. But it will etch to a deep black and you can feel a structure after a day on damascus blades. I use it everytime for damascus blades. Some weeks ago I have found a pamor lancehead on a fleemarket and the coffee worked better than ferric acid. To bring out a deep structure on my damascus I start with sulfuracid to „make the structure“ first. But the colour is often gray with that and the coffee afterwards brings out a deep black on the none nickelsteel. I do not know what the coffee makes with the surface. But the black colour seems to be relative stable against new rust. With ferric I have sometimes the first slight red rust after seconds and you are not fast enough with cleaning it. I have made some copper/iron mokume gane some weeks ago and the coffee is able to make the iron black without etching the copper. So it is a wide field for testing.
My experience with antique wootz blades is , of course, a minor experience. I do not have so much of them. 😢And as I said , each blade will etch different.
Hope I can help a little bit.
Best Thomas
|