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57534

Electrolysis Option for Stripping Paint

By: Tharran Gaines

In previous articles on Agriculture.com, you’ve read about a number of methods for removing paint and rust, including media blasting and soda blasting. What if all you had to do to remove paint was drop the part in a container of water?

Electrolysis isn’t quite that simple, but it has been the answer some restorers have been looking for to clean small to medium-size parts. 

“From my experience, electrolysis is by far the best way I have found to clean all sorts of iron and steel parts,” says Kevin LaRue, a Ford tractor enthusiast from Mineral, Virginia.

Exchanging ions
In simplest terms, electrolysis is a method of removing rust (iron oxide) by passing a small electrical charge from a battery or battery charger through the rusty metal to stimulate an exchange of ions while the rusty metal is submerged in an electrolyte solution. 

The part that needs to be cleaned is placed in a solution of water and washing soda, and then it is connected to the negative cable from a battery charger or battery. Meanwhile, the positive cable is connected to another piece of iron or steel, known as the sacrificial electrode, which is placed into the tank.

“The setup is really very simple,” LaRue says. “First, fill your container with water. Then stir in about 1/3 cup of washing soda for each 5 gallons of water. Place sacrificial steel electrodes around the edge of the container, and tie them together with wire.”

LaRue uses wire fencing as sacrificial steel. In addition to providing a massive amount of surface area that surrounds the part 360°, the material is self-supporting around a tank’s perimeter. 

“Hang the parts to be cleaned from a steel or copper wire positioned in the middle of the container. Be sure the part to be cleaned is immersed in the water and does not touch the sacrificial metal at any point. It’s also important that you connect your positive lead to the sacrificial electrodes and the negative lead to the part you want to clean.”

Becky Hansen, who collects tractors with her husband, Jeff, near Lake Wilson, Minnesota, says she has been using electrolysis to clean parts for up to two years now. In fact, she has removed paint from parts as large as the hood from a Case 400 High-Crop. 

“I’ve found that it can even loosen parts that are rusted solid,” she says. “I had a steering box from a Case tractor that was frozen solid. I put it in the solution for several hours. When I took it out, everything on it moved. It may take a while, but it works.”

How does it work?
LaRue says, based on his observations and expert studies, electrolysis works by converting rust to iron oxide (a black powder). 

“The gas bubbles forming on the good steel help loosen and push off the paint and rust. However, some of the rust also appears to get ‘plated’ onto the sacrificial metal,” he says.

Electrolysis tips
The following are some basics provided by LaRue, Hansen, and others who have had good success stripping parts with electrolysis. 

The electrolyte is the washing soda and water solution in the tank. You only need about 1/3 cup washing soda for each 5 gallons of water or 1 rounded tablespoon of soda per gallon.

This is not a case of more is better. Too much soda can increase conductivity to the point it burns out the charger. Also, most all electrolysis advocates recommend Arm & Hammer Washing Soda, which is usually sold as a laundry booster. This product is, however, not the same as baking soda. 

“If you can’t find the Arm & Hammer brand product, look in swimming pool supply stores for a pH booster, such as ph-UP,” LaRue  says, noting that the latter may be more concentrated and require less material. 

On the other hand, Hansen says she has had the best results with a mixture of regular baking soda and powdered Tide detergent. When filling a 55-gallon plastic barrel, she simply dumps in one full box of baking soda and one scoop of Tide (using the scoop that comes in the box).

Regarding the solutions tank, you never want to use a metal container since electrolysis depends on a current moving from the part to be cleaned to the sacrificial metal. Most any plastic container will work well including plastic buckets, storage tubs, and 55-gallon barrels. Hansen says she uses a 100-gallon Rubbermaid stock tank for large sheet parts like hoods and fenders.  

Electrical charge
While many restorers have had good luck connecting a battery charger directly to the metal pieces, others recommend placing a battery in the circuit. 

LaRue says he uses the 2-amp setting on his 2/10-amp charger to keep the battery charged. “Using the 10-amp setting just wastes energy and makes more heat,” he says. “Higher current settings may remove paint slightly better, but once the paint is loose, taking the part out and brushing off the loose stuff works better and saves more time than using higher current settings.”

Hansen connects the charger directly to the components. However, both restorers agree that some automatic chargers do not filter the AC power as well as they should. Any AC power that gets through the charger into your electrolysis tank slows down or can even stop the process. If your system does not seem to work well, try putting a 12-volt car battery in the circuit.

No matter how you set it up, though, make sure the negative clamp is connected to the part to be cleaned and the positive charge is connected to the sacrificial steel. Reverse this order, and your vintage part will become the sacrificial metal. 

It is permissible for the negative clamp to be submerged in the solution, but if the positive clamp touches the liquid, it also becomes a sacrificial metal, corroding the clamp. 

While some people, like LaRue, have found it beneficial to use fencing or rods that are wired together around the sides of the container as the sacrificial steel, other restorers use a single piece of sacrificial steel in the solution. 

Hansen, for example, uses one large piece of metal, which is clamped to the side of the solution tank so it doesn’t fall over and hit the part being cleaned. 

Safety tips
This electrolysis process does generate hydrogen and oxygen gas. These gasses are very flammable, particularly if they’re allowed to accumulate.

So do not smoke or use an open flame around the tank or in an enclosed shop where the stripping is taking place. It’s also important you disconnect the cables at the battery or unplug the charger before removing any parts, to avoid producing sparks. 

Always wear goggles and rubber gloves. “Some people add lye or other ingredients,” LaRue says. “I don’t believe the health risk is worth any benefit these products may have. You might as well just use chemical paint strippers and rust removers.”

Final cleanup
It generally takes several hours or even overnight to clean a part. Once it’s pulled out of the solution, final cleaning is often as simple as using a wire brush or scrubbing pad to remove any remaining residue. Hansen says she uses an air hose to peel off all the loose paint. Some parts, including sheet metal, may also require light sanding. “After cleaning, the part will have pits and valleys where the rust used to be,” LaRue notes. “Electrolysis will not fill those voids with new steel.”

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