The Electrolytic Rust Removal Fac
Ted Kinsey

I have had a couple of requests for this recently and there are a lot of
new subscribers, so here 'tis again. I hope I have covered all the points
so we don't start the thread again.

Q. What is the method?
A. A technique for returning surface rust to  iron. It uses the effect of
an small low voltage electric current and a suitable electrolyte
(solution).

Q. What advantages does the method have over the old standbys, like
vinegar, Coke, muriatic acid, Naval Jelly,  wire brushing, sand blasting
etc. ?
A. These methods all remove material to remove the rust, including
un-rusted surfaces. With many, the metal is left with a "pickled"look or a
characteristic color and texture. The electrolytic method removes nothing:
by returning surface rust to metallic iron, rust scale is loosened and can
be easily removed. Un-rusted metal is not affected in any way.

Q. What about screws, pivots, etc that are "rusted tight"?
A. The method will frequently solve these problems, without the need for
force, which can break things.

Q. Is it safe?
A. The solutions used are not hazardous; the voltages and currents are low,
so there is no electrical hazard. No noxious fumes are produced. The method
is self limiting: it is impossible to overclean an object.

Q. Where did this method come from?
A. Electrolysis is a standard technique in the artifact restoration business.
I wrote this up for the Chronicle of the Early American Industries
Association a few years back. Most of the tool collectors around here use
it:

Q. What do I need?
A. A plastic tub; a stainless steel or iron electrode, water and washing
soda (NOT baking soda!!) and a battery charger. About a tablespoon of soda
to a gallon of water. If you have trouble locating the washing soda,
household lye will work just fine. It's a tad more nasty--always wear eye
protection and be sure to add the lye to the water (NOT water to lye!!!)
The solution is weak, and is not harmful, though you might want to wear
gloves.

Q. How long does the solution last?
A. Forever, though the loosened rust will make it pretty disgusting after a
while. Evaporation and electrolysis will deplete the water from the
solution. Add water ONLY to bring the level back.

Q. What about the iron electode?
A.The iron  electrode works best if it surrounds the object to be cleaned,
since the cleaning is "line of sight" to a certain extent. The iron
electode will be eaten away with time. Stainless steel has the advantage
(some alloys, but not all) that it is not eaten away.

Q. How do I connect the battery charger?
A.THE POLARITY IS CRUCIAL!!  The iron or stainless electrode is connected
to the positive (red) terminal. The object being cleaned, to the
negative(black). Submerge the object, making sure you have good contact,
which can be difficult with heavily rusted objects.

 Q. How do I know if it is working?
A. Turn on the power. If your charger has a meter, be sure come current is
flowing. Again, good electrical contact may be hard to make-it is
essential. Fine bubbles will rise from the object.

Q.. How long do I leave it?
A. The time depends on the size of the object and of the iron electrode,
and on the amount of rust. You will have to test the object by trying to
wipe off the rust. Ir it is not completely clean, try again. Typical
cleaning time for moderately rusted objects is a few hours. With heavily
rusted objects can be left over night.

Q. How do I get the rust off after I remove the object?
A. Rub the object under running water. A paper towel will help. For heavily
rusted objects, a plastic pot scrubber can be used, carefully. Depending on
the amount of original rust, you may have to re-treat.

Q. My object is too big to fit. Can I clean part of it?
A. Yes. You can clean one end and then the other. Lap marks should be
minimal if the cleaning was thorough.

Q. After I take it out, then what?
A. The clean object will acquire surface rust very quickly, so wipe it dry
and dry further in a warm oven or with a hair dryer. You may want to apply
a light oil or a coat of wax to prevent further rusting.

Q. Will the method remove pitting?
A. No. It only operates on the rust in immediate contact with unrusted
metal. What's gone is gone.

Q. What will it look like when I am done?
A. The surface of rusted metal is left black. Rusted pits are still pits.
Shiny unrusted metal is untouched.

Q. What about nickle plating, paint, japanning and the like?
A. Sound plating will not be affected. Plating under which rust has
penetrated will usually be lifted. The solution may soften some paints.
Test with a drop of solution in an inconspicuous place. Remove wood handles
if possible before treating.

Q. How can I handle objects that are awkward to clean?
A. There are lots of variants: suspending an electrode inside to clean a
cavity in an object; using a sponge soaked in the electrolyte with a
backing electrode to clean spots on large objects or things that shouldn't
be submerged (like with lots of wood)

Q. How can I dispose of the solution?
A. The bath will last until it gets so disgusting that you decide it is
time for a fresh one. There is nothing especially nasty about it-it's
mildly basic-so disposal is not a concern, except you may not want all the
crud in your drains.

Q. Can I use metal containers?
A. This is highly risky. Galvanized metal can introduce zinc into the
solution. If you have used lye, it will attack aluminum. You may have
problems with electrical shorts, etc. Stick to plastic.

Q. How can I clean odd shaped objects?
A. Be ingenious. Plastic PVC pipe and eave troughs, wooden boxes with poly
vapor barrier.

Ted Kinsey