Soldering joins two or more metal items by melting and following a filler metal (solder) into the joint. Soldering is different from welding and does not involve melting the work pieces. Nearly all solders contain lead, but some are now lead-free alloys, used for electronics and plumbing purposes. Soldering equipment can be hand-soldering tools, like electric soldering iron to hot-cut plastics. Soldering gun heats faster but has a larger and heavier body. Non-electronic applications include soldering torches and soldering copper among others.