Home designers and craftspeople sometimes rust galvanized steel on purpose to give it an aged, antique look. If you want to rust galvanized wire, you must make sure you there is steel underneath the protective zinc coating. There are three classes of galvanizing: Class I, II and III, with Class III being the most durable, preventing rust for up to 20 years. Zinc is very reactive to strong acids. After sanding off some of the zinc with high-grit sandpaper, you may choose to use vinegar and salt or muriatic acid solution to rust the wire.
Things You'll Need
2 oz. muriatic acid
2 feet 14-gauge copper wire
¼ cup vinegar
2 tbsp. salt
Newspapers or paper towels
Muriatic Acid Treatment
Treat steel with a diluted solution of muriatic acid, and it will rust rapidly--in a couple of days if the weather is warm and humid. If you dissolve some copper in the solution, as Metalgeek.com recommends, you are sure to get an attractive reddish-brown color.
Take two feet of 14-gauge copper wire, coil it and soak it in 2 oz. of muriatic acid for a week. Prepare a solution in a heavy plastic bottle and leave the lid loose. The gases from the reaction may cause the container to explode. This will make a concentrate solution for a half-gallon of patina solution.
Test the solution. It should be a greenish color, and it will deposit a bright copper layer on a piece of clean steel inserted into it.
Dilute the concentrate with water. Make a solution of 20 parts water to one part acid/copper mixture.
Apply the mixture with a plastic spray bottle, but understand that the acid will eat through the bottle in a couple of days. You might try using a plastic hand-pump sprayer with no metal components.
Vinegar and Salt Treatment
Mix 1 pint hydrogen peroxide with ¼ cup vinegar and 2 tbsp. salt. Depending on how much wire you have, you can either mix this in a jar and insert the wire into the mixture, or double or triple the mixture and apply it with a spray bottle to the wire.
Let the wire sit in the mixture for two days or continuously reapply until you notice that it begins to rust.
Remove the wire or stop applying the mixture when the desired amount of rust is present.
You can apply two coats of water-based polyurethane to the finished product to prevent it from flaking.
If you are worried that the wire will rust to the point of disintegration, use hydrogen peroxide to stop the chemical reaction.
Muriatic acid is extremely dangerous. It is highly corrosive to material and to human flesh. Protect your skin, eyes and clothing. Do not use it in the presence of children, pets or other people. Dispose of it properly and in accordance with any municipal hazardous waste disposal regulations.