Articles

Subscribe to RSS Feed

12 Steps for Successful Rhodium Plating

By Stuller Technical Team

With modern alloys, how do jewelers achieve a really white color? The answer to that question is Rhodium Plating. A quality rhodium plated finish should be standard procedure on all white gold mountings but this leads to another frequently asked question, how do I get a good rhodium plated finish? To answer that question let's begin with the basic principles. First and foremost the piece needs to be polished to a bright finish. And if the piece is not clean, it will not plate!


Twelve Steps to Successful Rhodium Plating



1) Polish to a brilliant high finish
2) Clean thoroughly in an ultrasonic cleaner
3) Rinse in distilled water.
4) Steam Clean
5) Electro clean: 120°F, 4 volts for 2 minutes in a stainless beaker with the positive lead attached to the beaker, negative attached to the piece being plated. OR 120°F, 4 volts for 2 minutes in a glass beaker with a stainless steel anode, positive lead attached to the stainless anode, negative attached to the piece being plated.
6) Rinse in clean distilled water
7) Activator: room temp, no voltage, 30 seconds
8) Rinse in clean distilled water
9) Dip in fresh distilled water (When plating silver, use nickel mirror or palladium solution 120°F, 2 volts, for 2 minutes using a nickel anode. Palladium is recommended due the large amount of people that have allergic reactions to nickel.)
10) Rhodium plate: Room temperature, 4.5 volts, 20-30 seconds, negative lead attached to piece being plated, positive lead to platinized titanium anode.
11) Rinse in clean distilled water
12) Steam clean then dry. Try using a blow dryer to heat dry the piece. (Allow item to cool before handling if going this route.)

Hepful Hints



- Use a gold hook to suspend object from alligator clip, never steel.
- Suspend object in solution with current ON
- Be sure voltage setting is constant when actually plating piece


 Critical Issues



1) Temperature Control: Minor changes = inconsistent and poor results
2) Current Control: Never more than 3.5 volts for Rhodium, 3.5 is better
3) Proper Rinsing: Using distilled water for about a minute

Safety



1) Safety glasses are a must
2) When skin contact occurs, neutralize with a paste of baking soda. Rinse with plenty of water.
3) Protect skin and clothing with rubber gloves and neoprene apron.
4) As rhodium plating may produce some acidic fumes, it is recommended to work under good ventilation and to wear a NIOSH approved mask when plating.


Troubleshooting



Rhodium plates black:
- Mounting is not clean
- Current is set to high, try lowering amperage 1.5-2 amps and longer times 1 - 2 minutes for best results
- Rhodium solution is contaminated. Give your bath a carbon treatment

Dark spots after rhodium plating:
- Make sure the piece is Clean, Clean, Clean
- Air bubbles are sticking to mounting, gently agitate to dislodge air bubbles

Rhodium looks frosty:
- Amperage is too high, reduce to 1.5 amps

Looking to setup a rhodium plating station? We made it easy to start with our rhodium plating kit.

Item #45-0150 includes the following:
- 10 amp rectifier (45-4030)
- Platinized titanium anode (45-0321)
- Stainless steel anode (45-0326)
- 3 - 600ml pyrex beakers (45-6400)
- 3 lip covers (45-6401)
- An immersion thermometer (45-6420)
- A double burner (45-7120)
- Activator (45-2040)
- Electrocleaner (45-2020)

For Gold Plating Add the Following:
- Pyrex beaker (45-6400)
- 24K Gold anode (45-0334)
- 14K Yellow gold plating solution (45-2120)

For Plating of Two-Tone, Yellow & White Gold Jewelry Add the Following:
- Masking Lacquer (45-7990)
- Lacquer stripper (45-7995)

Recommended Ventilation for Plating:
- Solder pure w/rhodium filter (47-4099)
- Ductless fume hood (47-3085)