One of my other projects is taking the subframes and running gear from a miata and putting a tube frame chassis on it. It's a kit car called an MEV Exocet. In removing the subframes and other pieces I came across a lot of rusty bits. I hate spending hours wire wheeling, sanding, applying POR15 rust converter, and a miriad of other techniques that require copious amounts of elbow grease to get a result that is still below a decent result.
This still requires a bit of scrubbing, but it's not nearly as involved. The big reason for using this technique is that I get to build another super sweeet project!
(Non-technical explaination) Electrolysis works by removing the rust, and other things like grease and paint, from the part by curring a current through a bath of water and detergent. The rust either falls to the bottom of the tank or adheres to the anode (positive connection). Attach the Negative to the part and the Positive to some other metal that will be in the bucket. The process is mostly line-of-sight so an array surrounding the part works best. You can also put an anode inside the part and clean the interior. Always be careful to not let the cathode (your part) and anode (whatever is attached to the positive) touch.
Essentially all you need is a bucket, a battery charger, some steel rods, and washing soda (also known as soda ash or sodium carbonate. NOT sodium BIcarbonate, thats baking soda, it'll work just not as well) at a ratio of about a teaspoon per quart in a non-conductive container.
This setup is good for small parts, but my parts are much larger, so I need a bigger rig. I have several transformers sitting around and doing some seat-of-my-pants calculations (i.e. guesses) I determined that I can use a couple of them in series to get my desired voltage and current. One of the things to note is that if you use too high a voltage you could cause hydrogen embrittlement in your parts. Higher voltage means you can get the parts finished sooner, but I'd rather not risk embrittling things I'm going to be riding on at high speeds. More current will speed the process too but is more easily adjusted. To adjust current you can either move the part farther away from the anode to reduce the current flow, or you can use less sodium carbonate.
The transformers I plan on using are from some old thermal label printers and are 120v:27v stepdown transformers, or a 1:4.44 ratio, and 200VA rating. Putting them in series will yield approximately 6v which should allow me to get about 30 amps of current safely. I'm going to use a switch to allow me to use the 27v for less critical parts.
I'm going to knock together the transformers and stuff this weekend and I'll try and build the tank, but that might take me a couple more days. The tank will be made from some old fence posts and pickets I have lying around and should be about 5' x 4' x 2' high.
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Too many irons, not enough fire.