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Formulas for silverplating solution

We have recently purchased this business and came with a silver plating plant that we make use of quite a lot. The only problem is we seem to have a problem with the solution we are using. It keeps burning and does not come out shiny enough. We first sand blast the item, then dip it in a caustic soda [affil links] bath, rinse it and then in sulfuric acid, then rinse it and then hang it in the silverplating bath.

TRISH SEQUEIRA
DURBAN INDUSTRIAL CONTACTS AND ENGINEERING - DURBAN, SOUTH AFRICA
2003

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First of two simultaneous responses --

Do a Hull Cell test on the solution and ask the supplier to sort out the chemistry. You may well find the bath is out of balance and needs a bit of tlc (tender loving care).

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2003

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Second of two simultaneous responses --

Hallo SEQUEIRA,

Tell us on which metal you are plating silver? On any metal if you want to plate silver you have to undercoat bright nickel. After nickel then electrocleaning, rinse, 10%sulfuric acid, rinse and silver plating. Regarding for burning maybe you had put high voltage. Lower the voltage about 2V to 3V.

Good luck,

Dipen Pattni
jeweler/goldsmith - Dar-Es-Salaam, Tanzania
2003

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First of two simultaneous responses -- 2003

Dear Trish,

Trevor is right first you should check the metal content and free potassium cyanide of the bath balance it. If still not o.k check voltage , organic additives and anode area in your bath.

Regards,

Qutub Saify
- Ajman, UAE

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Second of two simultaneous responses --

Trevor is right, you need an analysis to balance the solution. In case the silver content and free potassium cyanide are within spec, check carbonate. Above 100 g/l it will case dullness in the high current density. Now the most important thing is the brightener system. You do use a brightener I assume! Brighteners of silver plating solutions have a limited shelf life. Check the expiring date of the batch you are currently using!

Sara Michaeli
Tel-Aviv-Yafo, Israel
2003