Etching

Etching

There are several ways of getting the grain of the steel to show once the blade has been finished. The most common method is etching. I am not sure exactly how this process works, but when Damascus steel is etched the variations in the composite steels will etch at different rates. The contrast and depth depend on the dissimilar properties in the metals you have combined.

Prior to etching, the blade must be clean. I will scrub my blades with Fantastic until the water sheets on the surface. If necessary I will degrease with solvent, but always wash with detergent as the final step before etching. The first dunk is a quick one to see if there are any spots that were not clean. You will have to completely sand out the etch if you do not get it clean the first time.

This photo shows my acid workstation. It is is ventilated by a fan system directly located above the pvc pipes that contain my etchants. I currently have two tubes one containing sulphuric acid and the other ferric chloride. There are also various spray bottles one with ammonia and various cleaners. The bucket contains clean water and also visible are a variety of chemical colorations in jars and containers. There is also a box of baking soda for neutralizing the acid.

There are many possible etchants:

Ferric Chloride

I believe that ferric chloride is a caustic, chemistry is a distant memory for me, so if you know the correct answer please email me. It is slightly less dangerous and easier to work with. Most makers get ferric from Radio Shack and it is sold as Archer Etchant for etching circuit boards. You can also buy it in larger quantities from Cronite Engraving Supplies 1-800-252-2552. You will have to pay hazardous shipping surcharges, but they sell it in different concentrations, rated as Baums, whatever they are. You must cut the ferric with distilled water for it to be most effective. It needs the extra oxygen molecules to work and may be cut 2 to 1 or even up to 4 to 1 to give the cleanest etch.

Ferric builds an oxide immediately when the steel is placed in it. If you allow the oxide to build up, it will inhibit the cutting action and give muddy results. I recommend scrubbing off the excess oxides with a worn 2000 grit sand paper and usually etch for twenty to thirty seconds  at a time until the desired depth has been achieved. You need to have a bucket of clean water available when you are etching. To neutralize ferric, you spray the blade with ammonia and rinse thoroughly. If you notice that your blades darken after they sit for a while, it is because the ferric has not been completely neutralized. Rinse under hot water and it will set the black oxides, but care must be taken that the rapidly drying blade doesn't discolor and rust before you oil it. I use ferric almost exclusively now because it is effective and not as hazardous.