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Tarnishing on Silverplated products with rhodium protection

2005

I wonder if you can help, we are producing jewellery composed of brass as the base material and then we plate with 5 microns and then plate with rhodium flash plating.However, upon packaging in a non-sulfide box we found some slight moisture in the packaging due to humidity after arrival at our customers warehouse and then there were signs of tarnishing. Would the tarnishing be attributed to the humidity in the packaging or would it be from a problem with the plating finishing?

Thank you very much,

John Barnes
- Hong Kong

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Rhodium plating is porous, and a "flash" would not protect the underlying material from tarnish if sealed in moist packaging. In general, though, regardless of plating thickness or quality, shipping in moist packaging will usually ruin it.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2005

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Hi Ted,

Thank you for your kind reply and valuable information.

Can I solve the tarnishing problem by plating with flash silver over the cast brass item, then palladium flash plating and surface finish with flash plating of rhodium? Please advise!

Will this finishing last longer without tarnishing than just 5 microns silver plating and flash rhodium?

Thank you Ted!

John Barnes
- Hong Kong
2005

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First of two simultaneous responses --

I seriously doubt that you will see a significant difference from adding a palladium flash between the silver and rhodium. 5 microns of silver is not a lot of silver by anyone's definition, but I think the principal problem is moisture. Can you include those little packages of dissicant in the packaging to remove the moisture?

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2005

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Second of two simultaneous responses --

Hello Barnes,

You will need nickel undercoating to plate rhodium other wise your bath will have problem later on.

If you do nickel,rhodium then clear coat, it'll last longer and longer.

You can also do bright copper and brigth silver and clear coating this thing in India is normal.

Dipen Pattni
jeweler/goldsmith - Dar-Es-Salaam, Tanzania
2005

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Thank you Ted and Dipen for your valuable advice.

Regards from Hong Kong!

John Barnes
- Hong Kong
2005