Electroplating at Home

letter 18152

Electroplating at Home

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Hello!

I will be thankful if you can help: I am restoring an old motorcycle, and I'm facing troubles with electroplating some parts. I built my own kit with a lot of help + material from the local electroplater. But, although the procedure before plating, cleaning etc., I am getting very poor results. One of the problem was getting a good power source. I use a 88 amper car battery. The nickel is plated unregulary and very thick and breakable on one side and none on the other side of the part. The electroplater can not help me because that will force him to come over and I don't want to ask him. He has no idea what am I doing wrong (I showed him the piece) and said that it is a bad preparation. But I am following his instruction. What else can be the reason? Is the battery to powerful?

Michael Steinmann
- Israel

First of two simultaneous responses -- ++

Michael, it is DIFFICULT to electroplate. Please don't be distressed if you can't learn in a few hours what others have spent years trying to learn. Take your part to your plater friend, have him plate it, and see all the necessary steps at least once.

Do you know what the substrate is? Are you following the basic procedure for that substrate? Where did you get your nickel solution--does it have the necessary brighteners according to Hull Cell tests?

It is not impossible to plate with a car battery, but it makes a difficult process all the trickier. Have you tried plating test panels?

Ted Mooney, P.E.
finishing.com
Brick, New Jersey

Second of two simultaneous responses -- ++

The theory of electroplating is very easy but as you are finding the practice is much more complicated. I suggest you bite the bullet and pay a professional to do the job properly; at least you will have redress on the company if it goes wrong. You give no details of what you are doing or of the setup you have, so no-one can help you on the technical side. However, from what you say, I would suggest the following problems: 1) inadequate cleaning; 2) tank volume too small; 3) unbalanced anodes; 4) unscreened workpieces; 5) insufficient anode-cathode distance; 6) lack of control of amp-mins; 7) solution not in control. Even if you get this lot right, how will you be sure you ahve good adhesion of the nickel to the substrate, especially on a motor cycle, whwre you are exposing it to the elements of the weather. For your own sake, just spend a bit of money and get the job done properly and save yourself a lot trouble. You have made no mention of the environmental protection you are employing to ensure you do not harm your local area or its inhabitants; you must surely have a waste disposal procedure in hand!

Trevor Crichton
R&D practical scientist - UK

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Thank you all for your kind response. Here is my procedure:

Preparation: giving the part a bright clean finish. Washing with tinner ot whitespirt or benzin. Washing with hot soapwater. Then I rinse with water. Wash with hydrochloric acid for a minute. Rinse again. Wash with caustic soda.

Electric cleaning: Solution is caustic soda (60 gr for 1 liter water). Room temperature. The car battery as power source. The part goes in first as minus, after 1 or 2 minute I turn over the poles and its a plus. After 3 to 4 minutes again as minus and after a few seconds it goes out, under current, of course. The anodes are 2 steel plates, greet blasted and cleaned with benzin and hot soap water. I don't touch the part with my finger. Rinse with water. Wash with hydrochloric acid again. Wash with water.

Electroplating: Solution is professional stuff from my electroplater friend. Temperature is kept around 50 to 60 celsius. The nickel anodes are also supplied by my friend, he gave me some cloth bags from his workshop. Also professional stuff to wrap the anodes with. An aquarium compressor supplies air bubbles to prevent air caught on piece during plating. After 30 to 60 minutes its over.I give up, taking out my poor piece, disappointed. I use baths with about 20 liter capacity, plastic. The heather is from a kitchen kettle. I use a glass thermometer. That's all. I hope I didn't forgot something.

Thank you in advance.

Michael Steinmann
- Israel

First of three simultaneous responses -- ++

I'm assuming the parts you want to plate are steel. Your cleaning procedure sounds more than adequate--excessive even. I wouldn't do all that work with the current reversal; I'd just make the part positive. Your nomenclature for the hydrochloric acid activation step, calling it a wash, is misleading. You should have 30 seconds or more immersion.

But the problem sounds like it's in the nickel bath. If the plating isn't of relatively even thickness, you need to space the anodes differently.

You need to get a Hull Cell and test panels so you can determine if the sollution is functioning correctly, and find the bright range for the nickel plating. Then you need to make sure you are plating in that current density range.

Ted Mooney
finishing.com
Brick, New Jersey

Second of three simultaneous responses -- ++

It is some 30 years ago that I was a development engineer for electro-chemical production processes, and I may have missed something in the mean time, but:

-How is the placement of your anodes?
-How do you control your current density (amps/dm2, if I remember well somewhere around 8-10)
-How do you control your pH
-Most of all: why do you turn your polarity around? Doesn't make sense at all, as you are taking the materila, which you first applied, off again. The nickel anode always and continuously is positive, the object to be plated is always negative.

Check the adhesion of the layer by baking the piece at 80 C for 10 minutes; bubbles=wrong.

Ed Damvelt
- Mexico

Third of three simultaneous responses -- ++

As Trevor alluded and I agree; plating is tricky stuff, "Cleanliness is next to Godliness". Unless you wish to do this full time, keeping "a line" up and running is a full time endeavor, and it won't let you work part time. Here a pro is you best source.

P.S. Caustic alone is a terrible cleaner. You do not mention pH of tank 12 volts is probally high. Do you have brightner adds available? Some will vap off over time, kickers, etc.

Jon Quirt
- Fridley, MN

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Michael:

If I could suggest a few things as I am a hobby plater myself. Put your part on the shelf and experiment/learn with little pieces of copper pipe. So many times people wreck thier part trying to learn how to plate on it! If you look in the FAQ area (#5) on the Home page here, you will find some help for hobby platers. Good luck and look forward to hearing from you.

Tom Haltmeyer
- Peoria, AZ, USA

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