Step 1: Sanding
Bring your Damascus to a 400 to 600 grit finish. If you’re using muriatic acid, you can bring the Damascus up to 1200 grit, or you can leave it at 400 grit. Either is effective however the color contrast is darker with Ferric Chloride For ferric acid, keep the grit between 400 and 600. Do not buff before etching. Buffing closes the pores in the metal, which will keep the acid from absorbing, and you’ll end up with an uneven etch.
Step 2: Washing
To etch Damascus, it should be perfectly clean. Thoroughly wash your piece with pure alcohol or brake cleaner and pat it dry with a clean rag.
Step 3: Dilution
If you’re using ferric acid, dilute it with Distilled water to a 10% Ferric, 90% Distilled water ratio. Never use tap water, spring water, or filtered water – they will all cause problems with the etc. Be sure that your distilled water hasn’t been sitting for more than a year. Muriatic acid needs no dilution.
Step 4: Warming the Acid
For both muriatic acid and ferric chloride, the temperature should be between 70 and 100 degrees Fahrenheit, about room temperature. If you need to warm your acid for use, the best method is to place your container of acid into a large bowl of warm water. **Never put acid in the microwave**
Step 5: Submersion Etching
Hang your damascus piece in the container of acid so that it hangs freely and doesn’t touch the sides or bottom of the container. Leave submerged for 60 seconds then pull the damascus out of the etchant and brush the entire surface of the damascus with a soft bristle toothbrush, this will help remove any residual oil or grease that you might have missed during cleaning, and help to brush away the dissolving material as the acid does its job. After brushing submerge the damascus back into the etchant and leave it submerged for 15 minutes.
Step 6: Neutralization
Remove your Damascus piece from the acid and submerge it into your baking soda bath for 5 minutes to neutralize the acid. Pat dry. After neutralizing, spray damascus with WD-40 and hang for 3-5 hours which can darken the color contrast.
***You can repeat steps 5 for a deeper etch if you desire***