My preferred method of removing rust is one that doesn’t require alot of manual labor or work. Several years ago I discovered the process of Electrolysis and since I’ve used it primarily to remove rust and paint from my machines. Benefits include:

• No excess material is removed – using abrasives to remove rust often removes some of the steel or iron as well.
• No caustic chemicals – the by-products of electrolysis are not really hazardous (with the exception lead, if your parts have lead-based paint on them).
• Cheap – the cost of electrolysis is a lot lower than sandblasting, chemical stripper, etc.

Come along while I explain the materials needed and the process.

Basics

Rust is chemically known as Ferrous Oxide. Basically, it’s formed by oxidation. Electrolysis is the process of reversing this oxidation.Basically, the parts you want to clean are placed in a solution, then electrical current is applied to the part and a piece of scrap metal that acts as a ‘receiver’ for the rust. This scrap piece is referred to as the Anode and over time it will be slowly worn away by the process, so only use something you don’t care about. I use re-bar for my anodes and have found that the slenderness and price make them perfect.

Materials

• Water
• Plastic container/bucket/barrel
• Sodium Carbonate (aka Washing Soda)
• 12 volt car battery charger (non-smart type)
• Scrap metal Anode (I really like using Re-Bar for this as I can cut it to length and it’s easy to find)
• Wire brush

Step 1: Mix the solution

The first step is to mix the solution. My main tank is a 50 gallon plastic barrel, which I fill mostly with water then mix in a couple cups of the Washing Soda. There has been debate about the best mixture ratio but most people concede that it doesn’t really matter. After you pour in the washing soda, you want to stir it really well to get the best mixture that you can.

Step 2: Attach everything

Proper setup of the wiring is critical. If you wire it backwards, your part to be cleaned will end up more rusty. The correct method of connecting the power is to connect the Negative (-) wire from the battery charger to the part you want to clean. The Positive (+) part get’s attached to the Anode.

Since the Anode ends up getting all rusty and corroded during this process it’s prudent to keep your Positive battery charger terminal out of the water. Since I use lengths of rebar for my anodes I usually make them tall enough to stuck out of the water a bit, then I can click the power terminal to the part that is not submerged.

For the connection to the part, it’s probably best to run a wire from your charger terminal to the part underwater.

A very important note: The anode and the part can never be touching while the power is on. If they touch at all, this short circuits the process. You don’t want that to happen, so make sure they don’t touch when you have the charger on.

If all is in place, and the anode and part are not touching, go ahead and turn on/plug in the batter charger. You should see the amp meter on the charger jump a little. After a while you’ll start to see some bubbles collecting at the surface of the water. This is good, it means that the process is working.

Step 3: Clean the anode(s)

After your part has been ‘cooking’ for a while, you’ll want to turn off the charger and inspect the anode. Usually after a little while it gets really cruddy, from all of the rust being transferred to it from the part. The more dirty it is the less effective it will be, so you need to clean it off with a wire brush often. The timeframe for this just really depends. Experiment with it and you’ll find a duration that works for you.

Step 4: Dry and wipe clean

After a while, once the process has run it’s course, you’ll want to disconnect power and pull your part out of the solution. You’ll know that it’s finished when there is no more red rust or paint and the surface is covered in a black sheen. That black stuff is Ferric Oxide, the neutralized version of rust. After you get your part out you’ll want to get it dried off to prevent it from rusting again. I use my air compressor for this, blowing the water off with a air nozzle. Sometimes I’ll even go so far as to dry it off with a rag. If you aren’t planning on getting to the part for a while you might want to coat it liberally in DW-40, although you’ll have to clean that off before you paint the part.

Sometimes after drying, there will still be some black ferric oxide on the part. This is really easy to remove, either by wiping down with a rag, steel wool, or a wire wheel.

Tags: electrolysis, rust