Where the
world gathers for metal finishing
Q&As since 1989


-----

Electro-etching brass rather than etching with nitric acid?

July 4, 2011

I have used nitric acid in the past to etch 16 gauge red brass but the nitric fumes are horrific to deal with. I was wondering if there is a reverse-plating technique that would strip metal off instead of depositing metal onto a piece of red brass. I know the leads would have to be switched, but what metal would be used for the cathode (or anode I don't know which)?
thank you in advance

Thomas Hanson
- Salt Lake City

Try very diluted nitric acid(2-3%) and brass or copper sheet as cathode.Hope it helps and good luck!

Goran Budija
- Cerovski vrh Croatia
July 8, 2011

Depending on your resist or ground sensitivity you may also try with diluted hydrochloric (muriatic) acid at 10% or sulfuric at 5%. When reverse etching your part becomes the anode. G. Marrufo-Mexico

Guillermo Marrufo
Monterrey, NL, Mexico
July 15, 2011

---

Reverse etching in hydrochloric acid works well to remove the alloying metals from the surface and also to etch the copper. The color should be a light salmon color. But, over etching produces a black smut of cupric oxide. An acid dip after electroetching will remove the smut.

Lyle Kirman
consultant - Cleveland Heights, Ohio
July 19, 2011