The process of electrolysis on iron relics

First of all, before we get started, let me warn you in advance that this is not a clean process.
If you are a neat freak, this is definitely not for you.
But, since you are reading this, you must be a detectorist, therefore not a stranger to getting a little dirty, so enjoy!

There are many uses of electrolysis on rusted items ranging from small nails to engine parts. Here in this forum I am going to detail only the methods that I have found to be beneficial to my own detecting uses. You can improvise and adapt from there depending on the items you are cleaning and what method you are comfortable with. The materials needed are very simple and you probably have most or all in your home right now.

A non-conductive container ( plastic, rubber, etc.) that can range from an empty butter tub to a 55 gal. drum.

A scraping or grinding device to obtain a good metal contact on the item to be cleaned or "soaked". Anything from a screwdriver, chisel, wire brush, Dremel or a grinding wheel will work.

Washing Soda such as Arm & Hammer. I have used baking soda and it will work fine, but the washing soda seems to generate more conductivity to the item and simply speeds up the process.

Sacrificial (*) stainless steel conduit. This can be as simple as a butter knife or a custom cut strip from a store bought sheet.

Sacrificial (*) alligator clips depending on what DC source you use. (see below in Prep)

A DC power supply with sacrificial (*) ends. AC will not work. This can be as small as a 300mA phone charger to a full 12V battery charger depending on the size of the item.

A rust inhibitor such as Permatex Rust Treatment. You can find this in the Midwest at most O'Reilly Auto Parts.

(*) The term sacrificial refers to parts that will need replacing eventually. These parts that are immersed in the water will deteriorate over time. However, I have yet to replace the alligator or battery terminal clips over the span of 3 years. Only the stainless steel strips have been neccessary to replace.

All photos contained in these steps are actual photos of my setup.

Preparation

First, you will need to establish a good metal-to-metal connection between the item to be soaked and the DC power to be applied. Scrape, brush, grind, whatever it takes to get right down to the metal. All you need is an area slightly larger than the clip that will be on it. I personally do both sides of the object where the 2 sides of the clip attach for maximun contact. Now set up your container/containers. Fill the container with enough water to cover the item fully leaving no part of the item dry if possible. Now add your washing/baking soda. The basic guideline I use depends on the size of the container. You may have to add/subtract to allow for the variables involved i.e. item size, how solid your metal connection is, etc. The water can be used over and over again until it stops working, or in most cases, I just change it out whenever it gets dirty and clouds my view on how effective the system is working at the time.

Butter tub size=1-2 teaspoons

Paint can size=3-4 tsp. (remember, non-conductive container ( plastic, rubber, etc.)

5 gal. bucket=approx. 1/2-1 cup depending on how much water you will have in the bucket. (I have never used a larger container than a 5 gal. bucket yet)

Now prep your DC power to be applied. Battery chargers will already have clips on the terminal ends. If you are using a low voltage supply such as a phone charger, you will need to snip off both ends that connect to the item to be charged and connect an alligator clip to each.

Set-up

Pictured below are my 3 different setups I use depending on the size of the object to soak and the conductivity of my connections. Different items will need different kinds of power on them. You will just have to experiment and see what works best for your items. On the left is my small bucket I use for square nails, washers, buckles, etc. For this I use the power adapter with alligator clips connected to the cut off end. The middle is for larger buckles, knife blades, padlocks, etc. On this I use a medium sized battery charger with a 6V/12V switch so I can toggle back and forth if I need more or less power. On the right is my large setup for axeheads, farm implements, and larger iron items. This power is a full-on 12V big charger set to max.

Now you are ready to "Soak"!

After adding the washing soda to the water, attach your terminal clips to the object. I will use the small setup on the left above for comparison. The Negative (usually always black) connects to the item to soak at the point of where you ground off the rust to get a good metal connection. The Positive (usually always red, but can be white, as above) connects to the stainless steel conduit ABOVE the water line. Set your conduit so that half stays above the water and the rest below the water. I like to bend mine out a little so it protrudes out into the water away from the sides of the container. Keep your item and conduit as close as you can, but DO NOT let them touch, as this will cancel out any results and possibly short out and causing the potential for an electrical fire. The small setup on the left has been prepared before applying power to it and is not bubbling yet. When you plug in your power, the Negative terminal, the item and the end of the steel conduit should start bubbling. The fumes rising from the bubbles are hydrogen fumes, so do not do electrolysis within the area of an open flame, and try not to breathe the fumes. As always, do this in a well ventilated area.

Best case scenario

Now let's look at the center picture above.

Best case scenario is to have your Negative power and your steel conduit on opposite ends of the item

The Negative terminal sends the DC charge through the whole item and the Positive steel conduit gives a line-of-sight charge to the other end via the water.

The Negative terminal and the end of the steel conduit will bubble no matter what usually. What your key factor will be is if the end of the item nearer the Positive conduit is bubbling, you have a good charge running the length of the item, and the rust is being eaten away from the inside of the item. Note that the entire length of the knife blade in the center photo is bubbling nicely and evenly. This is your best case scenario. Now look at the right photo. The steel conduit is not at the far end of the axehead soaking, yet the entire length of the axe is bubbling nicely. This is probably due to the fact I am running a full 12V into the water. I am trying to concentrate on getting the thickest part of the axehead clean first, and hoping the thinner side will de-rust about the same time as the thicker part.

After all your rust is electrolytically bubbled, simply wire brush the softened rust from your relic, dry thoroughly and use whatever rust treatment you prefer. The best I have found is Permatex Rust Treatment below. It is found here in the Midwest at most O'Reilly Auto Parts stores for around $6 a can.