Electrolysis Rust Removal

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theropod
Posts: 97
Joined: Tue Sep 20, 2016 11:12 am

Electrolysis Rust Removal

Post by theropod » Tue Nov 28, 2017 6:02 pm

Hey all,

I am restoring an early serial number 1938 Allis Chalmers model B tractor. The sheet metal is in terrible condition with rust and dead paint. I have been using direct current via a small 12 volt battery charger (<10amps) and employing electrolysis to dissolve the rust and loosen the paint. I cut the top off of a plastic 55 gallon drum and made a tank from that, and all the parts fit. This drum is filled with water and sodium carbonate (Arm and Hammer washing soda) for an electrolyte. The solution has a ratio of 1 tablespoon of the sodium carbonate to 1 gallon of water. The process works quite well but slowly. I understand that raising the amperage from the direct current source would speed this up, but buying a large capacity charger is not an option. Buying replacement parts, such as a carburetor and magneto, is already pushing my budget. My question is this; would providing a pulsed width modulation at a high frequency serve to knock the iron oxide molecules loose from the part to be restored faster, or would another method be better?

jremington
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Posts: 2268
Joined: Fri Jun 15, 2007 9:41 pm
Location: Eugene, Or

Re: Electrolysis Rust Removal

Post by jremington » Wed Nov 29, 2017 9:26 am

What are you using for sacrificial electrodes? http://antique-engines.com/electrol.asp

theropod
Posts: 97
Joined: Tue Sep 20, 2016 11:12 am

Re: Electrolysis Rust Removal

Post by theropod » Wed Nov 29, 2017 10:24 am

I am using soft steel rods very similar to rebar. A old tire iron, a spit from a long gone BBQ and a soft steel rod from a dead injet printer. No chrome and no stainless steel. I have also tested old web wire fencing and it works but is hard to clean off the gunk that collects as the process goes on. I wish I could find some large carbon rods as they erode far less and carry current better. Perhaps I am just impatient. It is absolutely amazing how very little cleanup is required after the process finishes to prepare the part for priming. With freshly cleaned anodes the amperage drop indicates little rust remains to be converted to magnetite and the process is completed. I usually apply a wire brush in my angle grinder to expose more surface area and then give the part a few more hours in the tank before rinsing, drying, hand sanding and deep cleaning before primer is applied.

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