Electrically Removing Corrosion and Rust

I inherited an antique dresser with slightly rusted hardware. One of the drawer pulls was particularly corroded. Some restoration was clearly necessary.

If you have:

In this case, the drawer pull would be too complex to machine and was unlikely to have an available replacement. I wanted to try to restore it, but feared it was too far gone for a chemicals or abrasives. An online search revealed a fascinating approach that converts rust using electricity. I felt this was exactly the right condition and the right type of piece to try the technology.

Restoring Antique Hardware

Here’s the drawer pull:

Drawer pulls: 1 mate, 2 rusted, 3 after electrolysis, 4 cleaned

1. Existing mating drawer pull (original condition)

2. Corroded drawer pull (before treatment)

3. Corroded drawer pull immediately after electrolysis

4. Corroded drawer pull after electrolysis, gentle scrubbing, and a light coat of oil.

As you can see, the results are stunning. I never would have thought that the rusted handle in image #2 could look as nice as it does in image #4.

Unfortunately, the patina and gold-green wash is gone as well, such that it no longer matches the other pulls. That’s not a big deal to me, since this dresser primarily has sentimental value and will be used throughout my lifetime, rather than sold. But, you should be aware that paint, tool markings, labels, and surface treatments may be removed by electrolysis -- potentially decreasing the market value or historical value of the piece.

Electrolysis Cannot Undo Damage

Electrolysis converts stubborn reddish iron rust to a black chemical compound that scrubs off quite easily. Simply stated, it uses electrical power to perform the opposite chemical reaction of rusting.

Sadly, steel and iron change shape when they rust, because iron oxide takes up more space than iron metal. This causes pieces to crack and flake off over time. So, although the rust can be removed, any shape or integrity damage remains.

Left: Rusted. Middle: Same piece after electrolysis. Right: Undamaged mate

Left: Rusted. Middle: Same piece after electrolysis. Right: Undamaged mate.

Although the rust has been miraculously removed, the pitting, cracking, and scarring remains. The undamaged (lightly corroded) mate does not have such damage.

No damage is caused by the electrolysis -- the damage is simply revealed after the rust is removed. In fact, later on I performed electrolysis on the remaining pulls (which had very little rust) and they looked fine, even under a magnifying glass. This confirmed that the observable damage was due to the prior rusting, not the cleaning process.

At a microscopic level, the cleaned iron is more porous than before it rusted, which means it is susceptible to future rusting unless it is covered by oil or a protective coating. This is why it is so important to protect your tools from rusting in the first place. Again, the porousness isn’t caused by electrolysis; it is caused by the rust removing metal particles bit by bit. Electrolysis isn’t a rust preventative, although it does provide a cleaner surface for you to seal the metal.

Any cracking or integrity loss due to rusting will not be fixed by electrolysis. If you suspect that rust has caused a critical mechanical or structural element to approach a failure point, don’t use the part. Electrolysis doesn’t weld the material back together or make it stronger.

Electrolysis cannot undo rust damage, but it can:

Next we'll see what supplies are needed and how the process proceeds.