Silver Plating Process Question

Fire those who are not following the procedure that you must surly have in place.

Why are operators allowed to change the process on a whim?

I agree that you need a standard procedure. If you have some workers dipping live, while others turn on power after submerged, you'll have an inconsistent product.

I did quite a bit of small batch plating when I owned my jewelry business. Granted, we mostly plated with rhodium (and sometimes gold), but I think the process of silver plating should be similar. I found that plating when live did create a "burnt" finish at times. As a science minded person, I also ran tests at higher voltages and found that a very uneven surface with pitting could occur. I found that the best finish was when I submerged first, then turned the power on - and turned the power off before removing the item.

Your decision will depend on the importance of identical products vs the finish of the plating.

Silver is the hardest metal to plate consistently. Anything that CAN go wrong WILL go wrong.

I found that the dip should be cathodic, but not full voltage...say, half or less. Then strike it with about 2 seconds of double voltage, then dial back right away to the recommended voltage.

If the "burnt" finish persists, then start changing variables one by one. There are so many other factors to consider, the purity of the water, the ph of the chemicals, the temperature of the shop, the type of electrolyte, and how much silver is dissolved in it, the material you are plating onto.... experimentation is the only way. Develop a procedure based on the experiments. You may lose some product during this time.

Silver cyanide is not used around here any more. I miss it. I don't miss trying to dispose of it.

Good day.

The purpose of going in live in the strike is to ensure there is no immersion deposit of silver which would give poor adhesion on the base metal,and affect the silver plate adhesion. You can see silver deposits on metals when the solution is dripped on metals (SS/ copper buss bars) without current being applied. Depending on the concentration of silver in the strike, the higher concentrations tend to give more immersion deposits without live entry, based on the substrate ie. nickel, copper, and thickness of silver plate. Typicaly, limiting to 0.5 oz/gal silver metal and potassium cyanide @ 12-13 oz/gal with live entry will ensure immersion deposit will not occur.

Live entry implies a measure of current applied to the cathode as it enters the solution. The amperage need not be high, as the first portion of the cathode entering the solution will be subject to high current density=burning. You need only a small measure of current when entering, and when fully submersed, full plating amperage can be applied. Limit your time (30-45 secs.), as excess time will show as brown, burnt deposits.

The purpose of the strike is two fold. 1)Ensures good adhesion/coverage on the cathode. 2)Ensures the plate bath will not be contaminated ie; nickel brighteners etc...

It is cheaper to purify/replace the strike than the plate bath.

The plate bath does not require live entry, as the cathode has a deposit of silver and immersion silver will not take place. As you well know, one can go directly from the strike to the plate without rinsing, but I like to inspect at each process stage.

Hope this sheds some light on your question.

Happy electrolyzing!

Regards,

Eric Bogner.