Build Your Own Electrolysis Relic-Cleaning Tank

Build Your Own Electrolysis Relic-Cleaning Tank

The find is only half the hobby. A plastic bucket, a battery charger, and some washing soda will pull a century of rust off an iron relic without grinding away the metal underneath.

$25–$50 Total Build Cost | 12V Battery Charger Power Source | 2–48 hrs Treatment Time | Washing Soda Electrolyte

Most people assume that cleaning up a rusted relic means a wire wheel, a chemical bath, or sending it off to a professional conservator. There’s a simpler option that relic hunters and bottle diggers have been using for decades: electrolysis. Run a low-amperage DC current through a tub of water and washing soda, with the rusted item as the cathode and a sacrificial piece of scrap steel as the anode, and the current pulls rust off the relic and deposits it harmlessly on the sacrificial metal — without dissolving the good iron underneath the way an acid bath or aggressive wire brushing would. It’s slow, it’s not glamorous, and it smells faintly of a swimming pool, but it’s the standard first step in stabilizing iron relics across the TreasureNet and metal-detecting forum communities, and it costs about as much as a fast-food order to build.

What makes it realistic for a beginner is that the entire setup is built from things most garages already have or can buy in one Home Depot run: a plastic bucket, a manual (non-automatic) battery charger, some rebar or scrap steel, and a box of Arm & Hammer washing soda. The only real engineering decision is what not to use — stainless steel anodes and table salt both produce genuinely hazardous byproducts, and every credible build guide flags this loudly. Below are the build references and forum threads worth reading before you wire anything up.

Electrical safety matters just as much as chemistry. Always unplug the charger before touching the water, the relic, the clamps, or any wiring — never connect or disconnect anything while the charger is plugged in. Run the charger from a GFCI-protected outlet (the kind already standard in garages and bathrooms) as a backup against shock.

BUILD GUIDES & STEP-BY-STEP REFERENCES

• Patriot Relics — How to Clean Iron Relics — patriotrelics.com — A relic-hunting-specific guide covering the full process from electrolysis tank construction through final preservation, with a clear recommendation to use graphite or mild steel anodes — graphite lasts longest, mild steel works fine but degrades over time.

• Practical Machinist — Rust Electrolysis Tank Setup, ver. 2.0 — practicalmachinist.com — A detailed, photo-heavy build using a 20-gallon plastic container with five rebar anodes wired around the perimeter for better “line of sight” coverage, plus community refinements like heat-shrink-insulated cross members and quick-disconnect anode connections for easy cleaning.

• Farmall Cub Forum — How to Build a 5 Gallon Electrolysis Tank — farmallcub.com — A simple, beginner-oriented build using a 5-gallon bucket lid with eight rebar pieces wired in a loop, written specifically to make the setup approachable for a first-timer using only hardware-store parts.

• An Adventure in Cast Iron — Building an Electrolysis Tank — theblackironblog.com — Originally written for cast iron pan restoration but directly applicable to relics; explains why the charger must be a manual (not automatic) model, since an automatic charger will sense the tank as a “full battery” and shut itself off.

COMMUNITY FORUMS & REAL BUILDS

• TreasureNet — Electrolysis, Build Your Own: How to Use and What to Expect — treasurenet.com — A long-running thread where relic hunters walk a newcomer through a minimal setup: an ice cream tub, a 6-amp charger, salvaged electrical-box covers as anodes — alongside warnings to never use the technique on copper coins.

• TreasureNet — Electrolysis Setup and Modifications — treasurenet.com — A more advanced builder documents years of refinements to a working setup, including faster ways to get a solid electrical contact on iron and a method for keeping anodes from fouling with cleaning residue.

• TreasureNet — First Try at Electrolysis Rust Removal — treasurenet.com — A documented first attempt on a 17th-century farm-site axe head, with before-and-after photos and the full 30–35 hour treatment timeline, finished with a Crisco bake to seal the metal.

• Cast Iron Collector Forums — Electrolysis Tank — castironcollector.com — A useful side discussion on tank material choice: plastic bins and trash cans are the standard recommendation, since a metal tank itself becomes an unintended anode and slowly corrodes through.

BEFORE YOU BUILD — NON-NEGOTIABLES

Every credible source agrees on the same two rules. Never use stainless steel as your anode — the process generates hexavalent chromium, a known carcinogen. And never use table salt as your electrolyte — it produces chlorine gas. Washing soda (sodium carbonate) and a mild-steel or graphite anode avoid both problems entirely, and the process should always run outdoors or in a well-ventilated space, since it also produces hydrogen gas at the cathode.

Keep the energized tank out of reach of kids and pets — it’s just a bucket of water at ground level, and there’s no way to tell by looking that it’s carrying current.

Every credible source agrees on the same two rules. Never use stainless steel as your anode — the process generates hexavalent chromium, a known carcinogen. And never use table salt as your electrolyte — it produces chlorine gas. Washing soda (sodium carbonate) and a mild-steel or graphite anode avoid both problems entirely, and the process produces hydrogen gas at the cathode, which is explosive in confined spaces. Run the tank outdoors or in a garage with the door open — never in a closed basement or utility room — and keep it away from any open flame, pilot light, water heater, or spark source.