These are made either as hand-operated tools, or electrically-operated. While the usual name is “soldering iron” it is also called a “soldering copper” if it is hand-operated. To perform satisfactorily, this tool must have a well-formed, well-cleaned, and well-tinned point.
1. File all old solder and scale from point end. This is important. If neglected, solder and scale will prevent proper tinning of point.
2. Heat soldering copper to a dull red. Do not direct heat at point because of danger of burning it. Use gas flame, blowtorch, or charcoal fire.
3. File point to proper shape. Point should taper back to efficient working angle, depending on size of copper. Point should be slightly rounded.
4. Plunge red-hot soldering copper into cold water. This anneals copper, making it softer for filing, easier to tin, and more efficient at giving off heat.
5. File all rough spots from point end of copper, finishing with a fine file to a flat, smooth surface. This polishing makes tinning last longer.
6. Heat copper so it will just melt solder. Wipe copper on wet rag to clean surfaces. Place a few drops of solder on block of ammonium chloride (sal ammoniac). Rub copper on ammonium chloride and in melted solder until copper acquires a bright tinned surface.
7. Clean tinned point each time it is removed from heater. When pits form on copper back of tinned area, heat copper and dip in water to remove scale.
Electric Soldering Iron
Shape and clean point by filing. Tin point in manner similar to procedure for tinning soldering copper. However, do not use external source of heat and do not dip iron in water.