Letter 6062

Voltages for Brush Electroplating 

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My name is Don and I'm new to 'Brush Electroplating'. I have yet to plate my first piece. This is only a hobby, but I do have some technical questions.

These questions pertain to small parts from 10 mm up to 100 mm

1. Which gives the best results: brush or anode with with cotton?

2. I understand the size of the piece determines the amount of voltage. For small parts made of copper, nickel or silver, what is the best operating voltage and amperage rating for gold plating?(coating will medium to heavy)

3. Which power supply will give the best results for gold plating small parts only: Give voltage & amperage rating.

Donald H. Roberts
- Milledgeville, GA. 31061 USA

Donald,

First welcome to the world of brush plating. The answers to your questions are as follows:

1. I am confused as to what you mean by brush, we use anodes of various sizes wrapped with cotton or some type of sleeve (Pellon,Dacron, Wool, etc.). The wrapping serves 2 purposes, 1 it holds the solution while plating and 2 it acts as a barrier between the anode and the work piece.

2. The voltage for Gold plating should be kept low between 3-6 volts, if the Gold deposit starts to look dark simply turn down the voltage. The amperage rating will range from 1-3 amps depending on the size of the area you are plating and your voltage setting. On very small parts you may not even notice the amp meter moving.

3. With just plating small components you can use a small machine at 15 volts and 15 amps. You must also take into account the voltage and amperage required for the activators and any preplates that are needed, on small parts this size machine will work.

You can check our web site to see the decorative kits that we have. We manufacture systems for the hobbyist up to industrial applications. If you have any questions feel free to give me a call.

David Crocker
Brooktronics Engineering Corp. - Valencia, CA.USA

Thank you for the prompt and precise reply. It is greatly appreciated. As to your question about brush plating, some companies supply an electroplating kit that contains an actual brush with bristles. The handle is metal with horse-hair type bristles that disconnected to the positive terminal of the power supply. They just used a brush instead of an anode covered with a dacron sleeve. Would assume the dacron sleeve would give better results. Anyway,thanks again for answering my questions.

Don Roberts

Donald H. Roberts
- Milledgeville, GA. USA

Don,

I work in an electroplating shop. We used to do gold and silver plating, but have been out of the business for awhile. I electroplate cadmium in a large bath, but I also do stylus cad.

I agree with David Crocker, I have never heard of horse hair bristle brushes. First of all you must come in close enough of contact with a part to create uniform, even plating. The only way I know of that works well with any plating is the anode covered with a cotton insulator.

You can use platinum, stainless steel, and carbon rods as your "brush" I would recommend a variable 15 volt rectifier rated at 20 amps max output. You will adjust the voltage for plating. The current (amps) will follow with the correct amps. In other words, you will plate by voltage, not amps. Your surface area, in square feet, will determine your amps.

As David said, your appearance of the plating will determine your voltage. If it has dull luster, increase the voltage. If you have the voltage too high, you will develop nodules of the metal you are plating within your cotton insulator, and the plating will be pitted or burnt. Arcing will occur eventually.

Hope I have given you some helpful advice.....

Greg Ginsbach
- Seattle, WA, USA

I have one last question concerning the power supply. The two responses received so far advise using a power supply rated at 15 to 20amps. I've seen one advertiser that says it's possible to use batteries to brush plate. That would put the amperage used in the milliamp range. Is it advisable to use a 15 or 20 amp power supply for small work or can you use a small variable AC adapter, say 3 to 15volts DC at 500 ma? I don't understand why the high amperage rating is needed. If it is, I want to use the correct power supply for the job.

Thanks guys!

Don Roberts
- Milledgeville, GA

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