Don't let the title fool you this isn't automotive related. Anyway, I came across something very old, I mean like Civil War old (I think) either way its cast iron and I think it may be the back part of a small canon. Can anybody think of some safe ways to remove the rust without damaging the already brittle metal? Thanks in advance.

Not off the top of my head. Quite honestly most antique collectors prefer to have the piece in the way it was found. Cleaning it may not be such a great idea.

I had thought of that, but I thought maybe cleaning it would make it easier to identify what it actually is.

Preservationists use a process called reverse electrolysis to restore cannon balls and cannon. Try
http://www.treasureexpeditions.com/Reverse%20Electrolysis.htm

for a description.

i have seen that process before, they have that on Rolls Royces, and oil Tankers, they use Zinc plates to charge the metal so it cant rust.....anyway i'm done hijacking.

electrolysis would be the way to do it, here is the regular way.

http://www3.telus.net/public/aschoepp/electrolyticrust.html

It works very, very well. Wont do any damage to the metal and will leave it clean as new.

FWIW, ScanlaxJMO's process refers to plating an object, depositing a thin coat of a neutral metal (zinc) onto other objects. What we're looking at here is reverse plating, that is reversing the oxidation process.

sn0border88's process is the same as the one I identified and contains a pretty good write-up.

Caution, do this in a well ventilated area, preferably outside. Those bubbles you see rising to the top is hydrogen and oxygen resulting from water molecules being ripped apart by the process. Unless you're really fond of recreating the Hindenburg, avoid smoking and sparks.

however, you shouldnt use stainless steel. That puts the cromium in the water and is nasty stuff you dont want to mess with.

Also, using galvanized will result in a light green plating on the object. Dont know why, but it isnt what I desired. I would be intrested in trying aluminum sometime jsut to see what happens. Hoever for your purpose just use mild steel only. Get a few pieces of rebar and attatch them to lengths of wire. If ou want you could get a big rummermaid container and ley them in or suspend it in a large trash can.


Ive always been curious what would happen if I use a steel 55gal drum as the anode, and how fast it would break down.