Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
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How to make two-tone jewelry; masking for 2-tone plating
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Q. Hello,
We are electroplaters engaged in rhodium plating business since 25 yrs. We have to expand our business to imitation jewelry and in imitation jewelry we want to use white bronze. There are many problems we are facing while using bronze such as all the jewelry has to be done two-tone so we have to do masking and to remove masking. We're using NC thinner so it takes a long process and we could not match up the production.
So is there any other way to achieve high production or is there any way that we can use bronze in pen plating because in that we can achieve large production and in less time. Can you please give us the making of white bronze bath solution? What are the chemicals and their percentages needed for making a white bronze bath?
Thank you,
Plating shop - India May 8, 2009
A. Hi Mr Hiren Dhakan,
Is your white bronze attacking in the NC thinner, will the luster last long after removal of stop-off over two tone and how do you protect this from tarnish with out doing EP.Because White bronze will lose its gloss while stripping the paint, some times it will attack, as it is an alloy of Tin, copper, & zinc. Even if you strip paint by hand also colour of white bronze will not match rhodium. Upon Electrophoretic lacquer, white bronze will turn into darker shade and no comparison to rhodium.
Panjala Mukesh
fashion jewelry mfgr.
Hyderabad, India
A. Try 3rd edition of Modern Electroplating book (1974, page 530). More detailed description is in German book Handbuch der Galvanotechnik (Dettner, Elze) [occasionally avail. from eBay, AbeBooks, or Amazon affil links]. Hope it helps and good luck!
Goran Budija- Cerovski vrh Croatia
Q. Hello,
I am looking for a masking product for a two tone micron gold plating production of jewelry.
What would be the best product to mask the area that is not supposed to be plated?
What product should be used to remove the mask?
This will be used in jewelry production.
Thank you in advance.
- New York, USA March 15, 2013
A. Albert,
One plant I worked in used a product called "Microshield" from Micro products. It was a red, solvent-based product that was like a lacquer. You can get a fine edge with this. To make it a harder finish, you need to heat it slightly for a period, then you can add multiple layers. Instructions on the can. For clean up, you can submerse the part in MEK, which quickly dissolves the masking.
However it also pollutes the MEK and you will need multiple tanks of MEK, or fresh MEK to guaranty no staining in the end. What we did was have 3 small tanks; one polluted to remove the bulk of the mask, then one to wash off the polluted MEK, and finally one virgin MEK. The polluted was eventually discarded and the middle MEK was downgraded to the polluted tank and so on.
Bob Adams CEF
Tijuana, Mexico
A. Albert
The Microshield Bob mentions works great. We used acetone
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to remove it and employed the same 3-step wash to remove. It may not be cost-effective in a production environment depending on the detail to be masked. Tapes, hard and soft fixtures might be an option for simple geometries.
- Colorado Springs, Colorado
Q. Hello
I d like to make a 2-tone jewelry. This is a ring with a gem stone. Only the prongs and a few filigree details need to be gold plated. Gold plating thickness should be 2.5 microns.
The prongs and filigree to be plated in gold are quite intricate and small areas.
I am capable of plating the ring completely at 2.5 micron thickness.
I could plate the ring completely with 2.5micron gold and try to mask the areas id like to keep in gold and dip the ring into rhodium plating to plate the rest of ring to achieve 2-tone. But this is costly since I am plating the areas that will be white with 2.5 micron gold (and slow).
Any idea or product or a company that you can suggest that can get the job done?
Thank you in advance.
- new york, New York February 3, 2018
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?)
How to plate a ring in two-tones
Q. I have a 2-tone ring (yellow gold band surrounded by white gold bands on either side). I want to Rhodium plate the white gold portion and leave the yellow as is. Is that possible to do? If so, what is best way to have it done?
Thanks.
- Calgary, Alberta, Canada December 20, 2017
(To show dark relieved areas)
Courtesy: Balfour.com
Hi Tony. Yes it can be done, either by brush plating just the white areas, or by using a masking material on the yellow area before dipping the ring into the rhodium plating solution. Or possibly even by plating the whole thing with rhodium and polishing it off of the areas which you want yellow. Since I'm not the one doing it, I can't advise which method the jewelry artist should use :-)
If you look at a class ring, you'll see that the "high" areas are the natural color of the metal and it is the recessed areas that are "antiqued"; it would look funny and be unmaintainable to try the opposite. Similarly, if your design has grooves, you'll get a longer lifetime from it if the grooved areas are plated rather than the high areas.
Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
How to achieve two tone finish on jewelry?
Q. Hi ! I'm a brass jewelry manufacturer and my customers often request two tone finish on their orders. A brief info about the finishes we offer: For gold color we offer polished brass while for silver we do silver electroplating.
Let's take an example of a cuff. Sometimes customers request to have certain area of the cuff to be of gold color and remaining area to be of silver. We have tried several masking tapes / liquids to cover up the gold area but all of these wear off when they go into the silver electroplating solutions.
I do not know how these big jewelry brands offering flawless two tone finishes do it but we have a hard time fulfilling these requests from our customers.
I would appreciate if anybody could help me understand what is the right way to do two colors on one product.
Thank you
Shuaib
- Moradabad, India July 20, 2020
A. Hi M. The alternate approach is to do brush plating. Still you should be able to successfully mask, and I see two possible problems. First, the stop-off you are using may not stand up to cyanide ("the world's best cleaner"), but there are stop off lacquers that will. Inquire of Maskcoat LLC [a finishing.com supporting advertiser] or others who specialize in maskants for plating.
A second possibility is that the jewelry is not spotlessly, water-break free, clean. I mentioned that cyanide is sometimes called the world's best cleaner; as a result you can often plate in a cyanide bath even when the parts are not truly clean, but the masking may not adhere well enough in the case of not truly clean jewelry.
Luck & Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
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