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Gold plating parameters

Will you please help me in my personal project. This is regarding gold plating. I plan to do an evaluation to gold plate beryllium copper. I already have the facilities like rectifier, lab type plating tank [small one] and the solution. What I need now is a set of parameters. Having this I can start and do some adjustment until I get the optimum setting. I hope you can help me on this. Thank you very much sir. Regards,

Marlon S Hadarly
2001

2004

I would like to plate some very thin wires with a corrosion resistant coating. I have thought of two possible options, 24k gold or platinum plating.

I fully understand how to build rectification circuits and regulated power supplies, so I was thinking I may build my own supply and plate from there.

The wire is ~1mm in diameter and roughly half a meter in length per strand. It is also nickel in nature and so ready to plate with gold. I then thought of two possible methods for applying the plating, either by submerging or by using a brush method.

With the brush method, I would need to drag the wire through brushes, and I'm not sure the coverage would be 100%, as the wires are textured. The other method would be to submerge 6 or so of the wires in a bath of the plating solution at a time. I could make this bath using a long length of relatively thin diameter pipe so that I could not have to buy massive volumes of plating solution. I was then thinking of using a simple jig to pull the wires gently taught in the solution, keeping them from touching the walls of the bath.

I am having trouble with a number of things however. I thought it would be easier to ask these as numbered points. I would greatly appreciate any help with these that you can provide. I only ask that you are specific about whether the answers are for gold or platinum.

1) Is there a rough estimate multiple that platinum plating will cost relative to gold plating? Twice as much for example?

2) Would I be correct in thinking that the platinum plating will be less resistive to mechanical wear?

3) What voltages should I aim to design the supply for? I read somewhere around 3 - 15 volts is sufficient?

4) How many amps will I require per surface inch I wish to apply the plating to?

Again, I would be very pleased with any help on this.

Thanks!

John Heritage
Finishing - Wallasey, Wirral, England

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Whilst you understand the electrical aspects of plating, do you understand the chemistry? Gold plating will almost certainly involve the use of cyanides. If you are doing this as a hobby and at home, I would strongly suggest that you avoid cyanides because you will have difficulty in obtaining them and after you have used them, you have to dispose of them. Cyanides can and do kill people. Electroplating should not be considered as a "kitchen sink hobby", although there are some processes that can be safely done at home by the experienced person. Unfortunately I would not consider gold plating to be one of these safer processes. You will also have to take account of how you are going to prepare the metal prior to electroplating. This will involve using more potentially nasty chemicals. Your option of brush and immersion plating is quite correct, but the most usual process will be immersion electroplating. Nevertheless, both processes can be used with both gold and platinum.

Firstly, the cost of platinum plating compared with gold will be dependent on the value of the bullion. This changes daily, so check in the newspaper to see how the price trends are going. Generally, however, you can assume gold is cheaper than platinum.

Secondly, platinum is generally harder than pure gold, although you can deposit hard gold by using other additives. Gold is usually preferred for electronic contacts because it is more corrosion resistant and "smears" better than platinum, so it will give a better intimate contact. Thirdly, your voltage is about right, but it will be affected by the design of your plating tanks. Fourthly, the amount of current you need per unit area will be dependent on the efficiency of the solution you use, the thickness of metal you want and the time you have to plate it.

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2004

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2004

Non cyanide plating process for gold(19.century):

1 gm gold chloride
75 gm sodium phosphate
2,5 gm sodium sulphite
1 lit water,SS anode,cca.6 V

Platinum plating solution(19.century):

4 gm platinum chloride
100 gm sodium phosphate
20 gm ammonium phosphate
1 lit. water,platinum or SS anode

Good luck!

Goran Budija
- Cerovski vrh Croatia

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Hello, if your focus is on learning to plate wire keep going. With respect, I would suggest that it would be less costly and time consuming if you purchased actual wire made of gold or platinum. The wire would be more durable for harsh environments than a plated surface. If cost is a big issue you could even use a gold filled wire with excellent results. This type of wire has a layer of gold covering a base metal core and is thicker than most platings would be. From an efficiency standpoint there is no reason to burn Renaissance paintings to cook dinner.

Good luck,

David Vinson
Metal Arts Specialties - Leonard, Michigan
2004

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I liked your answer and especially your closing metaphor, David. I was born a few generations off the farm. As a child, my elders constantly used 'barnyard metaphors' that meant little to them, and nothing to me, but they used them nonetheless, so I've hated watching them drop out of fashion over my lifetime. I have no mental image of how a 'stuck' pig bleeds, or how slippery a greased one is, or the standard way to skin a cat, but I enjoy the expressions for old times' sake now that they're scarce as hens' teeth.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2003