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"Etching solution for brass"


Q. What is the etching solution used for examining the microstructure of Brass?

Kate Smith
- Perth, Australia

Ferric Chloride

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A. There are numerous etches for brass, some dip and some electrolytic. For simplicity try an immersion etchant such as 10 g (NH4)2S2O8 (ammonium persulphate) in 90 mls water run either hot or cold. Alternatively try ferric chloride with hydrochloric acid in water - there is a very wide range of these recommended:

FeCL3(g) HCl (ml) H2O (ml)
5 50 100
20 5 100
25 25 100
1 20 100
8 25 100
5 10 100

These will have varying affects depending on the alloy. Another one is nitric acid, but the ratio of acid: water depends on the alloy. One recommended mixture is 1:1 acid:water with 0.15-0.3% silver nitrate added

trevor crichton
Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK

September 16, 2010

Q. I would like to photo etch some artwork on brass. I have a screen printing business and use photo emulsion. I have a metal halide exposing unit and can make film positives. Can you recommend a photo emulsion that I could apply to sheet brass? Also maybe a good book on equipment and safety involved using ferric chloride. Do you know of any good books on etching with acid?

Bob Hodgin
Hobbyist - Banner Elk, North Carolina

Electrolytic etching of brass stains it blue

August 9, 2013

Q. I have a question on brass and what is happening to it when I apply electrolytic etching.
I used a piece of stainless steel and plated it with brass, then etched it with an electrolyte solution and the brass turned lots of different colors, mainly blue. Can someone explain what has happened?

Ryan Wirth
- Lambertville, New Jersey, U.S.A.

August 12, 2013

A. Hi Ryan. There is an excellent article on electroetching of brass at steampunkworkshop.com/electroetch.shtml. But your inquiry presents too many unknowns. Brass plating is usually much thinner than the depth of the etch. How thick is your brass plating that you are able etch into it without exposing the stainless stee? What is your etch solution?

Copper salts like copper sulfate are very deep blue, so it sounds like you are using or creating copper salts that are staining the work this way.


Ted Mooney, finishing.com
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

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