enough to remove oxide but not so hard as to scratch the iron plating can be used. A brass wire scourer, brush, or wheel on a bench grinder, can be used with care. Sandpaper and other tools may be used but are likely to damage the plating. Electro-static discharge Not all soldering irons are ESD-safe. Although some manufacturers' mains-powered models are built with the element shaft (and hence the tip) electrically connected to ground via the iron's mains lead, other models' tips may float at arbitrary voltages unless an additional grounding wire is used. Wattage The wattage of the soldering iron is one of the most important factors in a soldering iron. Most of the soldering irons used in the electronics have wattage in the range of 20–60 watts. Temperature-controlled soldering irons with higher wattage (40 W–60 W) are better than low-wattage irons. It does not mean that temperature-controlled soldering irons with higher wattage apply more heat to the solder joint - it simply means that temperature-controlled soldering irons with higher wattage have more power available to heat the soldering joint if needed. On the other hand, a soldering iron with low wattage (20 W–30 W) can lose heat faster than it can re-heat itself. This may result in poor solder joints, particularly when soldering bigger solder joints or thick wires. See also Soldering station Brazing — Joining metals structurally by the use of a higher temperature joining alloy than solder ColdHeat — A resistive "instant heat" soldering iron Soldering gun Welding — Melting two objects to be joined into each other References Electronics work tools Soldering 19th-century inventions American inventions German inventions