Removing Rust

[tmajor]

There is one aspect of my project, which i don't understand. I started with a 2" black pipe for the anode. While it worked, it didn't seem to be as effective as anodes of angle iron. At one point, I had the pipe and 2 angle irons in the bath and the pipe drew very little rust, as compared to the angle iron anodes. ??



The anodes can be cleaned off and reused.

 

[DJ54]

Pipe, possibly because it was galvanized, or black pipe, because seems they have some sort of coating. I don't know if that makes a difference. Angle iron is bare surface, and maybe more sq. inches of area to attract..??

 

[bigdeano]

Does this process leave a black coating when it's finished? Seems like I tried it a long time ago and it did that. Thanks.

 

[tmajor]

Does this process leave a black coating when it's finished? Seems like I tried it a long time ago and it did that. Thanks.

I wouldn't say "black coating" (but, maybe), but possibly black dust, which seems to brush off with wire brush.

 

[MossRoad]

There is one aspect of my project, which i don't understand. I started with a 2" black pipe for the anode. While it worked, it didn't seem to be as effective as anodes of angle iron. At one point, I had the pipe and 2 angle irons in the bath and the pipe drew very little rust, as compared to the angle iron anodes. ??

View attachment 515166

The anodes can be cleaned off and reused.

I don't see it, so I gotta ask... is there a wire going to the pipe? :laughing:

Anyhow, from what I've read and the several times I've done it, the electrolysis is kind of line of sight and distance sensitive. The closest anode to the work piece gets the most current and the most "action". Also, as others have mentioned, the composition of the metals in the angle might not be the same as the pipe and that can also have an effect.

From what I've read, rebar is a good sacrificial anode. I'm going to use that the next time I do it.

To date, the largest items I have done are the iron handrails for our front and back porch steps. They are about 5 steps high by about 6' long. I made a shallow pool out of 2X12's slightly larger than the railings, then lined it with thick plastic sheet. I set the rails on risers and used several pieces of angle iron for the anodes. Hooked it all up to the arc welder and it was done overnight. Repeated for the other railing. Worked great! :thumbsup:

 

[Steave]

MossRoad what amperage did you set the welder. Never mind I just realized my old buzz box is AC only. I'm assuming it would need to be DC. So IF I were using a DC welder do you set it for the lowest amperage?

 

[DJ54]

I think the lowest setting on my old Century AC/DC is 20 amps.

 

[bigdeano]

If you only have an AC welder you can put a rectifier diode in one lead to get DC. This also works great for welding thin metal with an AC welder that doesn't go low enough amps. It cuts the amps in half. I've welded 20 gauge with my 180A AC welder on 60A and a diode.

 

[JRobyn]

Bigdeano, you got specs and a source for a suitable rectumfinder?

 

[bigdeano]

Bigdeano, you got specs and a source for a suitable rectumfinder?

I just used one I had laying around. It was probably rated around 200A at 200V. It isn't critical. Try Digikey or Ebay maybe. You don't want a bridge rectifier, just a single diode.