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Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
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Chrome plating of Brass Q&A. Best type of brass?
Q. Hello,
I have recently sent a brass panel for decorative chroming. The results however were less than desirable. According to the chroming shop, it was because the panel had previously been sand-blasted and therefore it was difficult for them to polish it to the necessary finish. But they charged me a negligible fee as a result.
This piece of panel is the only one I can find these days. How can I solve this sand-blasted finish problem? Will plating more layers of copper or a thick layer of nickel help? Any comments would be greatly appreciated.
Thanks.
Kik
Shian Jer, Kik- Germany
1999
A. Shian,
While I obviously have not seen the brass panel you described, the finisher's response to you seems reasonable. There's an old saying in the metal finishing world, "you can't make jewelry out of junk." In other words, it's not reasonable to expect that a rusty, rough piece of cast iron is going to appear right and smooth after plating. If the brass panel had indeed been sandblasted it's quite likely they were unable to polish and buff the piece to a mirror finish. That is what is required to obtain a suitable chrome finish. The underlying metal must be polished to the finish desired prior to nickel and chrome plating.
I hope you can get a piece suitable for a good finish. Good luck in your endeavor.
Daryl Spindler, CEF
decorative nickel-chrome plating - Greenbrier, Tennessee
1999
by Weiner & Walmsley
on AbeBooks
(rarely)
or eBay
(rarely) or
Amazon
(rarely)
(affil links)
Q. I have a question . I have a piece of jewelry (bracelet) which I'm sure is brass. This piece was nickel plated but the nickel is but all rubbed off. Rather than go to the expense of silver plating (because the bracelet was only $20) I was wondering if it could be chrome plated and how expensive this process is . I would love a reply on how or how could do this .
Ace Diamond- Australia
2002
A. Hi, Ace. Chrome plating is a difficult process to do on a shape like a bracelet. Despite the slightly higher metal price, silver plating would probably be more economical than chrome.
Plating is labor intensive and the plater doing the re-plating will be spending his time on one bracelet rather than processing a rack of 100 or more bracelets like the original manufacturer did. So re-plating is expensive and you likely won't find anyone to plate it for $20 or less. Unless the bracelet has sentimental value, you'd probably be better off just buying a new one.
But one possibility if you rarely wear the bracelet, so the thickness and wear resistance isn't important, is a do-it-yourself immersion plating process. Please see our FAQ "Silver Plating at Home". Good luck.
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2002
Plating of 260 vs 268 Brass Alloy
Q. We plate several brass alloys with semi-bright nickel/chrome and bright nickel/chrome.
Currently we use 260 Cartridge Brass for many of our plating processes. Our company would like to change from 260 to 268 Yellow Brass. 260 is 70/30 and 268 is 65/35. The Pb content in 268 is double that of 260. We currently use a sulfuric/fluoride type acid salts. Will a brass alloy with more Pb require a different type of acid salt?
We have had plating problems with 'leaded brass' in the past, but I am not sure what the alloy was.
For our automatic antiquing process, we have been told that if we were processing a leaded brass we would need a different type of acid salt that would take a 'bite' out of the Pb film. Also, the antiquing process might be a problem because the color may not be identical as not all brass alloys will be changed to 268. This antiquing process goes right on to the brass substrate.
Suggestions/comments will be appreciated.
Thanks, GJS
Gloria SchwedlerCaptive Plating Shop - Indianapolis, Indiana, USA
2004
A. Lead is insoluble in sulphates and chloride. So called "acid salts" contain Sodium Acid sulphate which form insoluble compounds with lead. Stay out of it.
Make the final dip prior plating in 50%/vol Fluoboric Acid, Not a fluoride, use fluoboric acid.
Robert H Probert
Robert H Probert Technical Services
Garner, North Carolina
2004
Q. Dear Sir
I have a question about chrome plating on Brass. Is Material (CuZn39Pb3) suitable for doing chrome plating? Since I found information on the internet that said it is free machining and so it will have pin holes on the top surface after plating. If it isn't good for the chrome plating treatment what kind of brass will be good?
Thanks a lot your great comment.
Kennith
- Hong Kong
May 2, 2008
A. Free machining brass is a difficult substrate to electroplate because the lead smears over the surface; this can often be seen as a light grey coloration to the metal surface. The way that lead makes brass machinable is by the lead acting as a dry lubricant between the cutting tool and the workpiece, but it results in a thin layer of lead over the brass that will cause an adhesion problem with any deposited metal. The easiest way of overcoming it is to remove the lead with an anodic etch in fluoboric acid.
Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
May 6, 2008
? Do you plate chrome direct to CuZn39Pb3 (C38500) or do you plate a layer of Nickel (Watts Nickel or Electroless Nickel ) before you plate chromium? There is a difference.
SK Cheah- Penang, Malaysia
May 12, 2008
A. I agree with Mr. Crichton. The important step is the removal of lead in the way suggested by him. Otherwise, it really doesn't make much difference if you underplate or not with nickel. Adhesion will be marginal or zero.
Guillermo MarrufoMonterrey, NL, Mexico
May 12, 2008
A. I don't agree with my previous posters; the lead in machinable brass is present as small balls, its purpose is to have shorter metal chips during the machining operation, as the lead balls act as a predetermined breaking point.
If you use a cleaner that removes the lead (e.g. every ultrasonic cleaner will have this effect) you will leave a lot of small holes in the surface, which will result in pinholes
- Lucerne
May 14, 2008
A. Marcus, I am not sure you are right about the lead mechanism and I am sure that not all ultrasonic cleaners will remove lead. For instance a simple solution of sodium lauryl sulphate will not dissolve lead, with or without ultrasonics applied.
Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
May 14, 2008
Best type of brass for chrome plating
Q. My question has to do with the best brass alloy to use for machined parts that will be chrome plated and usually in small quantities. I intended to ask the plater for the triple chrome process, but am also not sure if it is necessary. These would be highly visible parts with some weather exposure.
Thank you,
manufacturer - Martinez, California, USA
March 24, 2010
|
A. Problem # 1--There is no universal definition of triple chrome plating! It is more of an advertising gimmick than a real thing. - Navarre, Florida March 26, 2010 A. Hi,  Anders Sundman 4th Generation Surface Engineering Consultant - Arvika, Sweden March 27, 2010 |
How to get very high quality Chrome Finish on Brass
Q. I'm in bathroom fitting field. I want to know about very high chrome finish on brass material and which technique we can use and which higher grade of chrome finish.
Ab Tal- UAE
November 2, 2017
A. Hi Ab Tal,
Please see our "Introduction to Chrome Plating" at https://www.finishing.com/chrome.shtml and then post your detailed questions.
Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
November 2017
Q. Basically we are in trading in UAE. We manufacture our product from china of bathroom fittings. That's why we need ideas for chrome plating because this china factory is fooling us on the name of chrome plating. We ask them for european quality plating look but they can't, and supply us low grade plated products. Let us know what we can do in this case for high grade plating on our products.
Ab Tal [returning]- UAE
November 6, 2017
A. Hi again, Ab. I hope you enjoyed our intro which explained what is involved in high quality chrome plating. After that, there really are only two choices: either you ...
- buy only from firms which already deliver top quality goods, or
- you write plating specifications, establish a properly equipped and trained QA department, and enforce in your purchase orders that you will not pay for any product which is not in accord with those specifications or fails the specified QA tests.
Realistically you probably need to retain a plating consultant to write those specifications and develop that testing plan, but a very good beginning would be to obtain a copy of the booklet "Quality Metal Finishing Guide for Copper Nickel Chromium Coatings" from www.nasf.org, which includes such topics as 'Specifying the Finish' and 'Testing the Finish'.
Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
November 2017
Chroming a Brass Fire Pole
Q. I'd like to install a fire pole in a very modern new home build in Canada and it seems that almost all of the poles are made of brass. This new home is seriously chrome finished so I was curious the best way in your opinion to get a brass pole to a silver looking finish? Is it possible?
If I had it chrome plated, would that wear off from continuous sliding use of the pole over time or is it fairly resilient? Any other options for changing the colour?
- London, Ontario
October 27, 2020
A. Hi Tim. It is certainly possible to have a brass fire pole chrome plated, but it might be easier and safer to buy a stainless steel one; they are commercially available and might be shiny enough. If anyone got hurt on a chrome plated pole and claimed it was too slippery, it might be tough to defend against.
While it's possible to do extremely high quality chrome plating, it's not easy to do flawless chrome plating on large one of a kind items.
Luck & Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
October 2020
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