Metal finishing Q&As since 1989
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Chemical & Electropolishing of Brass: solutions, procedures, references
⇦ (tip: readers rarely show interest in abstract questions, but people's actual situations usually prompt responses) 
Q. Would like to know about chemical Polishing for brass,
Matte to mirror.
Look forward to hearing from you.
Regards
Prasad
Process design - Thane India
September 15, 2021
Ed. note: Sorry, this RFQ is old & outdated, so contact info is no longer available. However, if you feel that something technical should be said in reply, please post it; no public commercial suggestions please ( huh? why?)
ASM Metal Handbook
9th Edition, Vol. 5
"Surface Cleaning, Finishing & Coating"
on
AbeBooks
or
eBay
or
Amazon
(affil links)
A. Hi Prasad. ASM Metals Handbook has some reasonably good info on electropolishing and chemical polishing of brass. But your inquiry can be read two ways, so it's not clear to me whether you are looking for general information about chemical polishing for lots of different situations ranging from matte to mirror, or whether you are looking for a miracle :-)
Luck & Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
⇩ Closely related postings, oldest first ⇩
1998
Q. Hi
I have a complex surface that is diamond turned similar to a rotating polygonal multi-facet mirror surface used in supermarket scanners. It is made of brass (I could get one made of aluminum). The diamond turning operation achieves a surface of less than 1 µm rms.I want to improve the finish to less than 0.1 µm rms to achieve an optically mirrored finish which I can bounce a laser beam off of at uniform reflectivity.
Can electro-polishing help? What are the limitations? Are there other approaches? What companies can perform such an operation? Note that the surface would be very difficult to hand polish as it is not flat or spherical.
Eric SwansonA. Eric:
In theory, electropolishing can produce about a 50% reduction in the surface RMS. It is important, however, that the diamond instruments used to machine the surface do not smear the metal. It so, you will probably be disappointed with electropolishing, regardless of the metal you use.
I should add that electropolishing of brass and copper is possible; however, the surfaces produced may need to be protected after electropolishing. Aluminum may need anodizing and brass may need chromating or lacquering to prevent corrosion. The post-treatments may affect the mirror quality you are seeking.
Ed BayhaMetal Coating Process Corporation - Charlotte, North Carolina
1998
Q. Hi,
We currently have brass items that need to be polished and clear coated. The polishing takes a long time and is labor intensive. I need to know if there is an electropolishing solution used for brass that is safe to use and low odor if possible.
Any help is appreciated.
Thanks,
Rob Henry- Cleveland, Ohio
2001
A. Rob -
There are chemical polishing systems for brass that are electroless and have low to no odor (also no chromic or nitric acids). Finishes from matte to high gloss can be achieved.
Dan Brewerchemical process supplier - Gurnee, Illinois
2001
Q. I have a two halves mold made of Naval Brass. In this mold there are slots 0.5 mm wide 1.2 mm deep. these slots are made using EDM technology. Is it feasible to improve surface finish inside the slots using electro polishing? required surface finish is better than 32 r.m.s. Metal removal should be minimal and even.
Best regards,
PINHAS GALLONMechanical Gyroscopes - JERUSALEM, ISRAEL
2003
"Mold Making Handbook"
on
AbeBooks
or
Amazon
(affil links)
A. I am not sure electropolishing can be used in polishing moulds because of the highly variable local current densities. However, chemical polishing can be done as has been done for some years. I recall a patent from about 1983 that describes a chemical polishing solution for copper and its alloys that uses "bovine vitamin B6", however, I do recall any other details. There is also an article in Transactions of the IMF from 1988 (vol 66 p 18-21) that may help, but that is about tool steels. I suggest you do a literature search and base it around 1975-present.
Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
Electropolishing brass ship clocks
Q. Dear sir,
As a builder of ship clocks made of Brass I like to electropolish the Brass by my self. How can I do it.
Blessings, ASA
Asa Bentor- Hod Hshron, Israel
2004
Q. Hello...
I want to know how can can I electropolish a brass part? We plate a brass part and sometimes we have to strip it. Then when we replate it, part is being tarnished. So if we polish a brush polish then O.K. But it's very difficult for us. If we find available electropolishing solution it will be very easy for us. I tried some formulas but I couldn't find the right formula. Could you give me a clue, if it's possible? Thanks.
Emre TunaEngineering - Istanbul, Center, Turkey
2004
Q. I want to ask you that is there any solution for the electropolishing of brass?
I want to know the electrolytic bath for this process of electropolishing?
STUDENT - DHANBAD, JHARKHAND, INDIA
June 28, 2008
June 30, 2008
A. Hi, Abhishek. Yes there is. A computerized lit search of a small specialty database (Metal Finishing Information Systems, England) showed seven references. Phosphoric acid seemed to be the most common electrolyte. If you have access to either the Electroplating Engineering Handbook [on AbeBooks or eBay or Amazon] or Tegart's "The Electrolytic and Chemical Polishing of Metals", they will help. Good luck!
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
Q. Dear Sirs,
We are manufacturer of brass chandelier. We polish brass parts mechanically and recently I am researching about electropolishing method.
I tested phosphoric acid and was not successful. Pleas tell me what is the suitable for brass parts
Regards
product designer - Tehran, Iran
February 16, 2009
A. Straight phosphoric does not work well on any metal. Also, you did not mention the amps per square foot or the applied voltage, the tank temp or the time. They are all factors for ELECTROPOLISH.
Talk to some commercial vendors. You may be able to find someone that sells a commercial chemical polish that will work well enough. If not, a commercial electropolish specifically for the type of brass that you are using will be the cheapest in the long run.
For home brew, check out expired patents on the internet for your type of brass.
- Navarre, Florida
February 18, 2009
RFQ: Hi, I am looking for electropolishing of my brass parts; can you do it?
Willy Koh- Singapore
April 28, 2011
Ed. note: Sorry, this RFQ is old & outdated, so contact info is no longer available. However, if you feel that something technical should be said in reply, please post it; no public commercial suggestions please ( huh? why?)
Q. Our shop is in need of a simple electropolishing setup for small brass parts (stamped). I've heard of citric acid [on eBay or Amazon] / reverse wiring them up. Tips? Advice? Thanks.
Matt Pisarcik- Phoenix, Arizona USA
November 29, 2017
Matt,
Brass can be electropolished by Universal Electrolyte.
adv.
Contact me directly for advise.
Anna Berkovich
Russamer Lab
Pittsburgh, Pennsylvania
December 11, 2017
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