Electrolytic rust removal

[joshuabardwell]

I decided to build a stick electrode caddy out of a piece of 4" pipe that's been sitting out behind my barn since I moved in here (and probably longer). One problem: how to clean the rust out of the inside of the pipe. A wiser person would have just bought a clean piece of pipe and gone from there, but I'm not one to do something efficiently if I can do it in some cobbled-together way that involves not leaving the house or spending any (more) money. I realized that electrolytic rust removal would be perfect for this job.

In case you're not familiar, electrolytic rust removal is basically the opposite of electro-plating, at least that's how I see it. Instead of plating the surface of the metal with another metal, you cause the rust to migrate off of the metal. You can read more about the process here: ELECTROLYTIC RUST REMOVAL (ELECTROLYSIS)

Lid of the bucket, holding the rebar in place. A rebar is in the center as well, to clean the inside of the tube.



Wired up together using 12 ga speaker wire.



The whole process simmering away.



I couldn't get my battery charger to work, because it's smart and it won't charge if it doesn't detect a battery, so I hooked the whole thing up to a 12 volt battery instead. I measured the current at 2 amps, which seemed safe enough. There is no fuse, though, so if something should accidentally touch and short, the battery could be damaged, but I think that's about the worst I have to worry about.

 

[CNC Dan]

so did it work, or is it still cooking away?

 

[joshuabardwell]

so did it work, or is it still cooking away?

Still cooking away. I checked about after about a half hour and could see a lot of progress, then I put it back in to let it keep going. I'll post some before/after photos once it's done-done.

 

[joshuabardwell]

... oh, PS, I read that I could put a 12 volt bulb in series with the circuit to keep current down and provide a fuse and safety against a short. If anybody was going to do this, that'd probably be a good idea.

 

[bigdeano]

I used this method to clean some heavily rusted diamond plate. It left a heavy black coating that I had to take off with a wire brush in a drill, but it came off easier than the rust would have. It sure made a gunky black mess in the bucket, but not a big deal. I bought some muriatic acid I'm going to try next time.

 

[Willl]

Did ya grab a 'before' pic of the pipe ?

 

[joshuabardwell]

No, but I have two of them.

 

[joshuabardwell]

Okay, here's a "before" and "after". Both of them had been brushed with a wire wheel to remove the worst of the rust. I think the result is pretty dramatic!



I do confess that the difference is a bit exaggerated by the fact that the clean one is still wet, but literally within minutes of removing it from the bath, it had developed a patina of surface rust that made the difference between them harder to see. The real difference is on the inside, which hadn't been brushed at all. What used to be a thick coat of rust turned into a thin black sludge that easily wiped off with a rag. Is it spotless clean? No. But it's plenty clean enough to spray "rusty metal" primer on and slap a coat of paint on. This ain't automotive body-work, you know?

 

[joshuabardwell]

Mark 2.0. I have a 12-volt tail-light in series, to act as a resistor and rudimentary fuse. I also realized that I could just plug the battery charger in parallel, and it would detect the battery and help keep it topped off as it ran the circuit. The circuit is drawing about 1.5 amps, whereas the charger only puts out 0.75 amps, so it won't exactly keep up, but it should help.

 

[charlz]

I used this method to clean some heavily rusted diamond plate. It left a heavy black coating that I had to take off with a wire brush in a drill, but it came off easier than the rust would have. It sure made a gunky black mess in the bucket, but not a big deal. I bought some muriatic acid I'm going to try next time.

I like vinegar. Likely takes longer, I usually leave rusted pieces in it for a few days giving it a scrub once a day or so. Nice part is I can just toss it on the lawn when it is 'used up'. Either the iron or the slight remaining acidity leaves a green spot on the lawn (we have pretty base soil and the iron is locked up by the calcium so acid helps a little).