Electrolysis for de-rusting

Posted by Puddin' Man on September 13, 2009, 3:25 pm

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."

Posted by Limp Arbor on September 13, 2009, 3:47 pm

> 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. Pi=

pes

> 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.
> =A0 Thx,
> =A0 Puddin'
> "Law Without Equity Is No Law At All. It Is A Form Of Jungle Rule."

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.

Posted by Puddin' Man on September 13, 2009, 9:59 pm

wrote:

>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.

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

>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.

I expect pitting where the rust occurred.

>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.

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

>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.

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."

Posted by Limp Arbor on September 14, 2009, 5:50 am

> On Sun, 13 Sep 2009 12:47:52 -0700 (PDT), Limp Arbor <limp_ar...@hotmail.=
com> wrote:
< snip >

> >The parts also seem to re-rust much quicker than raw
> >steel. =A0This seems to happen even if you thoroughly rinse and
> >immediately dry the piece.

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

Yes, I used washing soda.

The things I derusted were old tools so I didn't paint them. A rusted
solid pair of slip joint pliers that wouldn't budge now work like a
charm. They haven'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'm not subjecting it to 1,000+ temps.

You'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
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?itemnumber=3D95667-0V=
GA
or
http://www.amazon.com/Campbell-Hausfeld-AT1226-Sandblasting-Kit/dp/B0007D30=
DO/ref=3Dpd_cp_hi_1

Posted by Limp Arbor on September 14, 2009, 6:06 am

> > On Sun, 13 Sep 2009 12:47:52 -0700 (PDT), Limp Arbor <limp_ar...@hotmai=

l.com> wrote:

> > >The parts also seem to re-rust much quicker than raw
> > >steel. =A0This seems to happen even if you thoroughly rinse and
> > >immediately dry the piece.

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

> Yes, I used washing soda.

And no, it didn't strip the paint that was well adhered.

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