fhobson wrote:
I have come across an old Norris plane. The metal body is quite badly
rusted. What is the best method of cleaning it up? Any help and advice would
be appreciated.


This was posted on the rec a while back, but unfortunately I don't
recall who posted it so as to give proper credit.

Glen

Get yourself a cheap battery charger, a stainless steel rod, some
(Arm&Hammer "washing soda" (can be found in the laundry section of most
grocery
stores is sold as a "detergent booster"), and a plastic pail full of
water, a
non-abrasive nylon scrubbing pad, a roll of paper towels, and a tin of
carnuba paste wax.

Throw some washing soda in the water and swish it around to dissolve
it. Connect the rusty object to the - Terminal of the charger and place it
in the water, connect the steel rod to the + terminal and submerge it in
the water (make certain the two objects _cannot_ touch each-other... turn
the charger on and witness the bubbles. after a few hours the water should
be pretty disgusting, wherever there _was_ rust will now have a black
film on
it. Wipe the film off w/ the nylon scrubber and dry it _immediately_,
apply the paste wax according to directions on the container.
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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 over clean 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 electrode?
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 electrode
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. If 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
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 nickel 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.