Subject: rust removal (long)
Author: Zerhackermann .
Date: Jul 10, 2001, 5:49 PM
Post ID: 1707442494
as I was going through the Ambo, I mixed and matched parts from various
bikes. Some pretty wretched. As I got toward the end, I was bloody tired of
bench grinders, buffing wheels and scotch brite pads, lemme tell you.
then a guy from the /5 list I run dropped this on me. I tried it using a
2/10/70 amp charger, a steel rod and a lye and water solution. I did have to
crank up to 70 amps to get a reaction started, but once it got going it
worked well. I also pulled the part from the solution on occasion and
scrubbed on it with a wire brush to help loosen stuff.
is it faster than manual labor? no. it took several 3 hour sessions to clean
up the tail light bracket.
is it better? You bet. the electrolytic process hets into nooks and crannies
that a bench wheel or even your fingers don't go.
The result was a peice that would have lost a significant amount of material
to abrassive cleaning, looks almost new.
so I'll drop this on you and see if it can help some others.
All cautions apply. Lye is caustic and will burn your skin and eyes. latex
gloves are cheap and safety glasses a must.
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The Electrolytic Rust Removal FAQ
by 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.
What is the method?
A technique for returning surface rust to iron. It uses the effect
of an small low voltage electric current and a suitable
electrolyte (solution).
What advantages does the method have over the old standbys, like
vinegar, Coke, muriatic acid, Naval Jelly, wire brushing,
sand blasting etc. ?
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.
What about screws, pivots, etc that are "rusted tight"?
The method will frequently solve these problems, without the need
for force, which can break things.
Is it safe?
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.
Where did this method come from?
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:
What do I need?
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.
How long does the solution last?
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.
What about the iron electode?
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.
How do I connect the battery charger?
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.
How do I know if it is working?
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.
How long do I leave it?
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.
How do I get the rust off after I remove the object?
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.
My object is too big to fit. Can I clean part of it?
Yes. You can clean one end and then the other. Lap marks should be
minimal if the cleaning was thorough.
After I take it out, then what?
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.
Will the method remove pitting?
No. It only operates on the rust in immediate contact with unrusted
metal. What's gone is gone.
What will it look like when I am done?
The surface of rusted metal is left black. Rusted pits are still
pits. Shiny unrusted metal is untouched.
What about nickle plating, paint, japanning and the like?
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.
How can I handle objects that are awkward to clean?
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)
How can I dispose of the solution?
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.
Can I use metal containers?
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.
How can I clean odd shaped objects?
Be ingenious. Plastic PVC pipe and eave troughs, wooden boxes with
poly vapor barrier.
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