Electrolysis: It CAN be done at home!

[cti4sw]

So, I'd heard of electrolysis before but thought it was limited to hair removal so once I read about some of you using it to clean artifacts I had to find out whether it was a simple process or not. Some definitions for you:

Oxidation: any surface destruction caused by a chemical reaction involving oxygen; rust and silver tarnish are two examples
Corrosion: any chemical reaction that erodes a substance over time; oxidation is one form of corrosion
Electrolysis: sending electricity through a liquid to separate oxidation and/or corrosion from metals
Cathode: the negative side of the battery
Anode: the positive side of the battery
Solvent: the liquid used to conduct the current and separate the oxidation/corrosion from the metal

It is simple. It could be messy, but it IS a simple process.

You could do this one of two ways.... either way includes a small 10-gallon fish tank, two steel rods, jumper cables, and some sort of power source. So, the 2 ways would be a car battery for big artifacts and a 9-volt for smaller artifacts. In any case, the juice from the power supply must "outweigh" (so to speak) or be equal to the energy transferred and lost in the reaction.



I would probably either clamp or use electrical tape to secure the alligator clips to the rim of the fish tank. Having never done this before, I have no idea how long it would take to completely free the artifact of the oxidation. I highly recommend you disconnect the anode BEFORE you touch the water!!! I cannot stress this enough. Voltage alone will not kill you; the average static shock is 3,000 volts and Tasers use about 100,000 volts. But 0.050 amps can kill you if it passes through your heart, and this is amplified by the water you'd be using.

Anyone who tries this (or has done it before) please provide feedback...

~Jon

 

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[allen_idaho]

If you look up "Electrolytic Rust Removal", you can find detailed instructions on how to do this. I know for a fact there are one or two documents on the subject up at instructables.com

 

[U.K. Brian]

The more usual method is to use for smaller finds is to use either a battery or a train set/model car transformer to which alligator clips are attach. One clip is attached to the item to be cleaned (say a coin) and the other to a stainless steel rod (a stainless knife out of your cutlery draw will do fine). A jam jar or similar is used for the electrolyte solution (most add salt to warm water and may even add caustic soda or citric acid in a small amont as a cleaning agent) and the stainless anode is placed on one side and the item to be cleaned (which becomes the cathode) is lowered into the other.
In next to no time bubbles will start to come from the item you are cleaning. You cannot leave the process as it can be so fast in some cases that you end up frying the coin.

Avoid the anode and cathode touching though the low voltage from a battery should not cause harm and a train transformer will just blow its fuse.

If its just an odd spot or two on a coin its better to do localised electrolytical cleaning where the item to be cleaned remains attached to the cathode but a probe replaces the anode and the electrolyte is touched onto the area being treated with a fine brush or swab.

 

[cti4sw]

Sounds much better coming from someone who's done it before

 

[stevemc]

Dont use salt in the water, Never use salt, that is the worst thing for this. It will work to get corrosion off, but it will imbed salt into it, and it will fall apart. never use table salt. use washing soda, found in the clothes washing section of your super market, Arm and Hammer brand. It is Sodium Carbonate, do not use Sodium Bicarbonate -baking soda, also made by Arm and Hammer in the baking aisle. Do use stainless steel as the anode and cathode, use a stainless spoon, put the clamp on out of the water, leave the clamp out. Never use copper or iron. I find a power supply that is switchable is best. You can find these at Radio Shack. You must cut off the bitter end, and split the 2 wires, and attach clamps. When put in the solution, fizzing side gets attatched to metal object to be cleaned. Too much current-amperage, will eat up metal, good metal. And I am talking milliamps for small objects, dont mess around with battery chargers, unless you can control it very well, or just a battery, as all these will dump everything amperage wise, since it is a dead short to the battery or battery charger. Too little and it doesnt work well. I find that if you switch it until it starts fizzing slightly, that is best. Change out the solution when dirty. Probably a tablespoon of washing soda to a quart of water is good.

 

[U.K. Brian]

Quite agree that salt and metal are not good bedfellows but whatever is used it will have to be dealt with after cleaning has taken place. Salts that are a major part of the corrosion that has already taken place soon start a further electrochemical reaction leading to rapid damage.
This is where say for iron the item must be boiled in a 5% solution of caustic soda in distilled water. Several chages of solution are best. Then do a few boilings in pure distilled water and dry out in a warm oven. A final soak in acetone will then displace any remaining chlorides. Finally seal from the air with microcrystalline wax and seal with a conservation grade lacquer.

Gold and silver don't need the work iron does. Copper/brass, like iron, do need specially attention due to the dreaded bronze disease.

Whatever is used chemical wise in conservation care has to be taken that your not breathing in the fumes as your health may be damaged.

 

[cti4sw]

Gonna use a sodium bicarbonate/water mix during electrolysis. I have some test pieces I found this weekend. Anyone know how long I should do the electrolysis for?

 

[russ]

yep I got a small kit to do this bit of salt water and baking soda or lemon juice etc. works fine for lifting corrosion.