So etching the base metals is very similar to etching sterling silver, the only major difference is the chemicals used. The chemical used for etching base metals is Ferric Chloride.
Ferric chloride is a traditional home-use circuit board etchant. It’s easy enough to come by, and the Ferric by itself is no big environmental problem. However, once you’ve etched with it, you’re left with a solution with a bunch of copper chloride in it. This dissolved copper is an environmental problem, and you can’t just pour it down the drain (legally) — you’re supposed to take it to a hazardous waste facility. Plus, think about it…your pipes are copper…this is a copper etchant…not recommended that you pour it down your drain anyways. There are other recipes out there using hydrochloric acids and peroxide, but to me they are just as dangerous. Ferric chloride can be obtained either as a solid (not recommended as it can give off highly toxic hydrogen chloride fumes when mixed with water) or in liquid form.
I used to order my Ferric Chloride in powder form but found this is the worst way to get it. It requires you to mix it in water yourself and the reaction is pretty strong. The fumes from the reaction are really strong and the reaction between the powder and the water makes the solution really really hot. So in short I don’t recommend you buy this, instead I would buy the liquid form from Daniel Smith Art Supplies. There are no fumes and mess to worry about. 1 gallon runs about $20-25.
For disposal, look on your towns local website, they may offer a Hazardous Waste Day so people can drop off paints and oils. They will provide you with a list of items you cannot submit but Ferric Chloride is not on that list, so you can drop it off there.
The process to using the etchant is the same as Ferric Nitrate for silver. You want to agitate the solution for a nice uniform etch on your piece. Once you start to notice your etchant times becoming longer and longer, the solution is exhausted and its time to start with fresh. You can store the Ferric Chloride in any plastic container but I recommend a secondary containment for the plastic container if you plan to store it for a while. This will protect you from any potential leaks. You can neutralize the etchant by adding baking powder to the solution but I recommend adding a little bit at a time because it too has a violent reaction to the etchant. Neutralizing it just puts it in a safe state.
Give it a try! I find that I love to etch nickel the most because it gives the metal an natural patina antique look without the addition of patina chemicals. You will be happy with the results!
Feel free to add your experiences to this post so we can all learn from them and develop our own ideal methods :o)
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