The axe is etched with a solution of regent nitric and hydrochloric acid and water.
The axe is etched with a solution of regent nitric and hydrochloric acid and water.
The formula is: First mix 1 part nitric acid, 3 parts hydrochloric acid, then dilute that mixture with 9 parts water. This is a classical etching solution referred to as "Aqua Regia".
The axe was then coated with a mixture of heated bee's wax and asphalt. The pattern was drawn into the resist with a stylus then a clay "dam" was built around the area to be etched. Acid was poured into the area and watched occasionally. As the acid worked I brushed the bubbles that formed away with a birds feather. (Or you could use an expendable brush but the feather was cheaper.) After a few hours, the acid was removed and stored for later use and the axe washed with water.
Study your materials and always observe safety precautions. This stuff will permanently destroy your skin, eyes and lungs! I always work outside and have a bucket of water and baking soda handy to immerse or throw over spills, in case of emergency.
After-thought:
In hind-sight, I wish I hadn't acid etched the axe, as the Vikings did not use that technique. They did incise or engrave with chisels. Also The design is not so period as I now require of myself. :P
I may file it off. The pictures are enough. hummm.