Electrolysis for de-rusting

[Puddin' Man]

In chemistry and manufacturing, electrolysis is a method of using an electric current to drive an otherwise non-spontaneous chemical reaction.

I think it should be practical to use electrolysis to remove rust from my motorcycle header pipes prior to applying new paint. Could use some advice from experienced person(s).

Origninal finish on (steel) pipes was likely enamel, lasted 20+ years. Pipes are now moderately rusted.

I have a large plastic Muck Bucket and an 8 Amp (max) 12v trickle charger. Thinking of using a steel water pipe for an anode.

Could use washing soda or maybe lye (if I can find it) for electrolyte. Which would be better for removing both rust and old paint?

How long might it take to do such a job?

Any/all other info, suggestions etc much appreciated.

Thx, Puddin'

"Law Without Equity Is No Law At All. It Is A Form Of Jungle Rule."

[Limp Arbor]

Will probably take no more than 24 hours. The more you can surround the piece you are trying to de-rust with the sacrificial rod the quicker/better it will work. Best results I had were when I used chicken wire fencing to wrap around the entire container.

Unfortunately the process is not without side effects. I'v done it a few times and the derusted part ends up with a dull gray color and an odd texture. The texture could be due to the rust being 'ripped' away by the current. The parts also seem to re-rust much quicker than raw steel. This seems to happen even if you thoroughly rinse and immediately dry the piece.

With light rust and a pipes that will be painted anyway you're probably better off with a wire wheel in a drill to remove the rust then follow up with hi-temp rustoleum.

[Jules]

JOOI, what is the exact process? I'd always been told to use sacrificial anodes for rusty parts - and have done it several times - but the wikipedia entry seems to suggest that it only works to protect the cathode material against corrosion, rather than removing existing corrosion (almost implying that all that happens is that a new layer of material gets dumped onto the cathode material, trapping the actual rust beneath?)

Varies, I suppose. Last time I did it was on some big old chest handles a few years ago (same sort of setup as you, 12V capable of around 8A), and it ran for about 12 hours before it "looked" good. I honestly can't remember what I used for electrolyte now, though :-(

cheers

Jules

[Puddin' Man]

Hmmmm. I got some "hardware cloth" (very similar) ...

I expect pitting where the rust occurred.

Did you use washing soda (sodium carbonate) for electrolyte? Did it strip paint as well as rust? Did you paint immediately?

Motor is an I4, pipes are 4-into-1. Some surfaces are not readily accessable.

No rustoleum. I've got some hi-heat (1500 F) paint.

Thx, P

"Law Without Equity Is No Law At All. It Is A Form Of Jungle Rule."

[bud--]

Some links that have been posted here previously:

[Limp Arbor]

< snip >

Yes, I used washing soda.

The things I derusted were old tools so I didn&#39;t paint them. A rusted solid pair of slip joint pliers that wouldn&#39;t budge now work like a charm. They haven&#39;t rerusted because I rinsed them then immediately wiped them down with a light oil.

An old hand plane that I derusted did start to rust quickly even though I thoroughly rinsed & dried it then put it on top of the clothes dryer to warm it up. The top part I painted and that seems to be holding up pretty well but I&#39;m not subjecting it to 1,000+ temps.

You&#39;re going to need a pretty big container to fit a header into, no? Maybe a plastic trash can.

You could also go with instant gratification and blast the pipes

or

[Limp Arbor]

And no, it didn&#39;t strip the paint that was well adhered.

[Joe]

Electrolysis is totally impractical. Take the parts to any automotive machine shop (or serious bike shop) and have them glass bead blasted. The parts come out perfectly dry and ready for paint after a quick air spritz to remove dust. Takes about

10 minutes on average.

Joe

[Puddin' Man]

I don&#39;t think much of that particular wikipedia entry. Very easy to mis-interpret. Try these, or others posted this thread:

P

"Law Without Equity Is No Law At All. It Is A Form Of Jungle Rule."

[Puddin' Man]

The Muck Bucket I have is like the bottom half of a plastic trash can. I don&#39;t need to do the muffler, pipes are maybe 30". Might be close, &#39;tho.

Interesting that they market lo-cost sand-blast eqpt. I don&#39;t have a compressor.

Thanks, P

"Law Without Equity Is No Law At All. It Is A Form Of Jungle Rule."

[Jules]

I admit it didn&#39;t seem to be very well written!

Thanks for those - much appreciated! :)

cheers

Jules

[Tony]

I use diluted muriatic acid, and sometimes full strength. Outside only and don&#39;t breath the fumes.