Our museum has had a group of ACL and SAL steel open end and adjustable wrenches of various large sizes donated. The tools had been in outdoor storage and have a layer of scale on them, but not so bad that the stamped markings are totally obliterated. I'm wondering what should be done to conserve these tools. Manual wire brushing or maybe a wire wheel? Should they be coated with anything, or treated with Ospho (or similar rust conversion product) after the loose rust is removed? There are no immediate plans to display them, although as the Transportation Annex develops I'm sure I will designate space for RR tools. Your thoughts and suggestions appreciated.

It depends on whether or not there is any finish remaining, and how bad the rust is. The best action is to preserve the tools without removing any remaining finish or metal. That means no bead blasting, sanding or wire wheel or brush.

I would start with an oil called Break-Free. You can usually buy it at sporting goods or gun stores. It will penetrate the rust and leave a protective coating on the metal. Available in spray and liquid. Apply and wipe down with a rag. It will stop the rust from spreading. There are some other products available that work as well. Unless the rust is severe, I would not attempt removal.

For rust removal, I would get the brown 3M pads. (Green is more available, but more abrasive and will remove the finish.) Hardware store, tool supply. Use with the break-free as a lubricant. Use with care, scrubbing too hard will remove the finish.

After cleaning, the best preservation is an annual recoating with break-free.

Steven,

Rust removal by electroylsis is a very good way to remove rust and preserve the details still on the steel objects. I've been cleaning artifacts recovered from the iron ore mine sites I'm researching here in B'ham.

I can get the steel to a silver gray color, and high light the fibers in wrought iron. If I can figure out how to post pics here...

We can perform electroylsis cleaning service if you so desire.

Robert Yuill

Electrolysis would get my vote. Can be done in a small plastic garbage can with a battery charger and some scrap iron anodes. For more detailed discussions on the process see the Old Woodworking Machine sites and do a search of topics and messages. www.owwm.com or www.owwm.org

Then add a rust inhibitor finish.

Bob Kutella

Stephen: call Rudd. He ran a laboratory at the RH doing metal conservation for several years.

dave

From Robert Yuill:

Attached is a pic of a tram car bumper cap that was cleaned with electrolysis. This is a good example of the surface finish that can be achieved, although it took a month of low voltage and low current to produce the cleaned object.

I thought about electrolysis later. It has good & bad points.

The negatives. It will loosen any existing finish on your part. Items begin rusting as soon as the process is stopped.

Positives. Does not remove any metal. Takes a lot less work.

Here is a good article on electrolysis.
http://www.stovebolt.com/techtips/rust/ ... usting.htm
I have found lye to work better than washing soda. Baking soda takes forever. Also, you need an older battery charger, one without a computer. The newer chargers need some voltage present to get started, that way you can't hook it up backwards.

Another option is the use of sugar to remove rust. Looks like a good method that won't loosen an existing finish. http://www.stovebolt.com/techtips/rust/ ... lasses.htm
There is truth to the coke or pepsi stories about removing rust.

I have tried using coke poured on a rusty Mamod steam toy, which I then carefully scrubbed with a piece of aluminum foil. Sure enough, it took the rust off, and left behind the metal. I have not idea what it would do to an existing finish; other than to say it did not take any of the paint off that I could see.

I do not think it is the sugar (fructose corn syrup) in the Coke that helps remove rust, but the low pH. Coke is a dilute solution of phosphoric acid if not mistaken.

Bob Kutella

That's correct; I had a can of something diet that I wouldn't have drank anyway and tried it; it worked just as well. Any flavor soft drink will also work.

I don't know what else is in the Coke, but the carbonated water is carbonic acid:

http://en.wikipedia.org/wiki/Carbonated_water

Cola soft drinks contain phosphoric acid, most 7-UP-type and fruit-flavored ones don't. Some of the latter contain citric acid. Carbonated water is carbon dioxide dissolved in water, forming carbonic acid (CO2 + H2O = H2CO3). Carbonic acid is a very weak acid; citric acid is stronger, and phosphoric is the strongest of the three.

Any of these must be declared on the label, so if you find what works best, check the ingredient statement. The "secret" stuff in Coke is listed as "flavorings."

The above information is from my memory, and I've been retired for 11 years, so...........

Jim Baker, retired food additive chemist

I have used a product that does very well. I used it on an old corroded ticket punch. It works by decomposing the oxidized compound and removing the oxygen and leaving only the metal. It's totally biodegradable and is an amazing product.

http://www.rusteco.com/

I have a cousin who had the same thing done to her upper lip.

:-)