A short course in the basics of brass maintenance

 

Yellow Brass, the most common brass used for decorative metalwork, is an alloy of copper and zinc combined in a ratio of 70% copper to 30% zinc.

Brass naturally oxidizes to a rich brown patina. In the presence of caustic substances, the copper in the alloy produces the familiar green patina called verdigris.

Cleaning & Refinishing

When removing any substance from the surface of brass, take care not to scratch the brass. Never use abrasives such as sandpaper, steel wool or wire wheels. Scratches in brass require a great deal of abrasive work to remove and blend.

Caustic substances such as salts and acids will etch the surface of brass, resulting in pit marks that cannot be polished away by hand. Once etched, the only way to repair the surface is to level the pitted area. This typically requires powerful machinery and involves the removal of a fair amount of brass.

Use warm water with mild detergent and a toothbrush to remove encrusted polish that has been left for a long period of time.

When using a tool to remove foreign debris such as wax, the best material to use is wood or plastic. Never use an object harder than the brass itself to remove old lacquer, paint, wax, etc., and never use a tool on lacquered surfaces.

To remove lacquer efficiently, use a paint stripper such as Zip Strip® or 5f5®. Perform the work outdoors and follow all safety precautions on the label.

Sometimes, wax can be removed from non-lacquered brass by immersing it in boiling water. Be sure that the piece can be drained and dried both inside and out before submerging it. (Water left standing in the hollow base of a candlestick or vase can slowly leak out and spoil the finish).

If a non-lacquered piece cannot be submerged, scrape off all wax with a wood or plastic tool, then use acetone or another solvent to remove the remainder. Acetone must be used outdoors in a well-ventilated area. Be sure to follow all safety instructions.

If the wax-covered piece has a lacquered surface beneath the wax, take great care to avoid damaging the lacquer. The best approach is to use a heat gun or a powerful hair drier to warm the wax to a point where it can be wiped off with a soft cotton cloth.

Polishing

Solid brass can be polished by hand repeatedly for years without showing signs of wear.

People often make the mistake of attempting to polish through protective lacquer coatings. To determine whether the piece is lacquered, test a darkened area by putting a dab of Wright's Polish® on the area in question. If the metal doesn't brighten under the dabbed spot, the piece is probably protected by a layer of lacquer.

Polishing brass with brass polishes is much easier if you first remove all foreign substances, such as dirt and lacquer, in addition to the oxidation.

Some polishes contain deoxidants, which help in the removal of oxides.

Most brass and copper polishes will get the job done, though they all require elbow grease. We recommend Nev-R-Dull® because it is easy and non-toxic, and it doesn't leave a white residue in the cracks and crevices. For tough jobs, Wright's Polish works well to remove stubborn oxidation. However, since it contains a deoxidant, it is important to remove any remaining residue after using Wright's Polish.

Polishes like Nev-R-Dull contain a cotton wadding that is soaked in a solvent similar to kerosene. Once the solvent has evaporated, the polish no longer works.

Cream polish contains fine granules of pumice that both remove the oxides and level the surface, imparting a bright shine. These polishes are best when used in combination with a cotton cloth or soft paper towel.

After polishing, always remove any remaining polish residue that may have crept into cracks and crevices.

Lacquering

Once polished, brass can be sealed and protected with a number of different substances. Lacquer is a substance most commonly used to protect shiny brass surfaces.

Nitrocellulose lacquer has been in use since the 1800s and is the most common surface protectant. Many brands of cellulose nitrate-based lacquer are on the market in spray-can form, and a skilled painter can apply them quite successfully.

Waxing

Clear acrylic waxes such as Future® floor wax are less permanent finishes that can be removed with most brass polishes. They are best used on pieces that will not be handled often. Acrylic waxes sometimes produce a rainbow-refraction effect on the surface that can be a bit distracting, so take care to achieve an even finish on smooth surfaces.

Microcrystalline paste waxes, such as bowling alley wax or butcher's wax, are very effective sealants. Waxes apply and buff out very nicely, and they are easily removed with brass polishes. These waxes hold up quite well and can also be used to protect lacquered surfaces.

Unlike lacquered brass, waxed brass items can be spot-polished and re-waxed as needed.

Storage

Before storing polished brass items, it is best to rub them down thoroughly with a soft cloth to ensure that all salt and oils from fingerprints have been removed.

When storing brass, the best protection is a sealed plastic bag with a desiccant pack to absorb any moisture. Avoid contact with rubber bands, brown paper or other materials that may contain oxidizing agents. Never store brass in plastic stretch wrap commonly used for food storage.

If you are ever in doubt about how to proceed on a decorative metal project, don't hesitate to contact our friendly staff. We are always happy to help!