Rust is the ancient enemy of metal, and the needlegun scaler is part of the modern arsenal against rust. Small enough to be held in one hand, the needlegun scaler, also known as the needle scaler gun or needle gun, is a pneumatic tool that uses tiny chisels whirling at high speed to quickly remove rust, old paint and corrosion from hard metals.
Perhaps best-known for its association with the U.S. Navy and the cleaning of old ships, the needlegun scaler has also migrated into common use in the home and car repair. It is valued for its ability to poke its rapidly moving "needles" into tight places, and also for the speed with which it can reduce a surface to bare metal. It is driven by a small piston moving back and forth faster than the eye can follow — ranging from 2,500 to 5,000 times a second — and can automatically adjust to contoured surfaces.
As its popularity has grown, the needlegun scaler has been manufactured by a number of power tool makers. Most scalers are operated by compressed air, but electric models have also come to the market. Generally, they weigh less than five pounds (about 2.3 kg).
Manufacturers recommend that any surface to be treated by a needle gun scaler first be cleaned of surface oil and dirt. The tool is most effective when applied to small areas at a time and held at a 90-degree angle. Because the chisels only need to move a small distance because of their speed, the needlegun scaler is also able to put a fine edge along the borders of surfaces.
The variations between scalers on the market generally have to do with the number of needles and the speed with which they move. The force of the cleaning action can also wear less expensive scalers out quickly, so it is important to determine how much the tool will be used. One should note too that the needlegun scaler is not a quiet tool, and some operators may choose to wear ear plugs.
It is also not recommended for use on softer surfaces such as aluminum, wood, chrome, brass, lineoleum or stainless steel, because the needles may actually scour the metal surface beneath the rust and paint. Heat can build up rather quickly around the business end of a needle gun scaler, but it quickly dissipates when the tool is switched off to recharge the compressor.
Most hand-held needlegun scalers sell for less than $50 US Dollars (USD), making it a practical tool for do-it-yourselfers.