Electrolytic polishing

Electro stripping can de done to brighten gold. This is done using a DC power source and a solution that contains cyanide. The cyanide dissolves the surface layer of copper and silver that is alloyed into the gold.

As far as the actual polishing there are are several mechanical production methods that can be used. Are you working with new castings and fabricated pieces?

We are working with new castings and fabricated pieces. in gold and silver.

Do you think the procedure will damage the gold and silver pieces?

Do you have the formula for the cyanide solution?

Eric

I dont have a formula. I have used cyanide eggs for brightening. There is also a process called bombing with cyanide. Since cyanide is potentially very deadly some of the manufacturers are using a non cyanide product. I suggest doing a google search for electro polishing. I have also used magnetic polishers uning stainless steel needles in a bowl spun by heavy magnets. This gives excellent cleaning down into all of the little nooks and crevices of the cast piece. you still cant beat hand finishing. I can also suggest some products for that.

Rustyh2o

all suggestions are wellcome

My granddad was a jeweler and used to use sodium cyanide eggs dissolved in water for brightening gold, just brushing the pieces with a nylon brush after they had been placed in the solution for a few minutes. I have no doubt that electro stripping can be done as you state, but I don't know whether it is necessary.

Electropolishing is a process that looks a bit like electroplating, except upon close examination, you discover that the leads are hooked up backwards, taking material from the workpiece and depositing it on the anode! It works surprisingly well.

You have to start with a polished surface though. The electropolishing will get down into areas where the buffer won't go.

It also takes a long time, and the results are a bit funny. I got it to work on nickel, but it failed on stainless steel...made the stinless steel frosty. The high carbon steel turned jet black, but with a very high polish. (useful, maybe, in the right place!) I could not get rid of "fire mark" from gold with this method...it might need research, so I concluded that it was electropolishing was useless for gold, even with a cyanide electroyte.

I brightened gold without cyanide by using copper sulphate, and hooking up the work so that the workpiece was the anode....the electricity pulled the copper out of the surface of the gold alloy, leaving pure gold behind. (I didn't have any cyanide solution at the time, and was a bit desperate.) Two minutes did the job at room temperature. I understand that this is a way to do fakery, so be cautious. And it didn't remove fire mark either! Often temperature is critical for anything involving gold.

I presume there are MUCH more knowledgable people than me who have done this, and I hope to see some replies. All I place before you here are some of the discoveries I have made from my experiments involving gold, steel, copper, and nickel plating during my career as a knife maker.

Here is one Magnetic tumbler. Many sizes and price ranges are available

I really do not understand how it works. Are the piecies been moved by magnetic field?

The tub on top holds the castings in a non sudsing soap and water solution. An electric motor in the bottom spins the permanent magnets. The magnets then in turn spin the stainless steel needles in the tub with the castings, soap and water. You can get very good results in a few hours. Smoothing will occur along with firescale removal fromthe casting or soldering.

"It also takes a long time, and the results are a bit funny. I got it to work on nickel, but it failed on stainless steel...made the stinless steel frosty. The high carbon steel turned jet black, but with a very high polish. (useful, maybe, in the right place!) I could not get rid of "fire mark" from gold with this method...it might need research, so I concluded that it was electropolishing was useless for gold, even with a cyanide electroyte."

Electropolishing like electroplating is more of an art than a science. The place where I worked 30 or more years ago made ashtrays from as received, mill finished, stainless steel sheet stock, press stamped about 3/8" deep with holder grooves in each corner. the were then sent to the plating department which electropolished them to a bright, but not quite a mirror finish.

It's all in how you hold you mouth! :-)

Electropolishing

A bit of advice, when anyone uses "stainless" to categorize all stainless steels, look for the largest grain of salt and take it.

17-4 stainless in the H900 condition responds quite nicely w/o pre-buffing. The polishing takes place by removing any ferritic particulates from processing and asperities. Closely held tolerances will be lost.

Parts subjected to this process are held on a rack and all will have a different material removal amount. For anything that is appearance based, this will not be cause for heartburn.

Hello Guest, Have you electro polished any 304 or 309 stainless tubing?

No. Google around for a vendor and ask them to do a sample for you.

I'd echo that comment, our parts in 304 stainless electro-polish nicely but 410 parts come out smooth & matt.

would rather do the polishing myself. I have equipment for mechanical polishing.300 series SS responds well to electropolishing in an acid bath I have read.

Nigh, So you do electropolishing in your business? Do you use a heated sulfuric acid solution?

We sub contract the electro polishing to Anopol & just do bright dipping, lapping & lap polishing in-house.