• A soldering gun is a useful tool for home repair and art projectsSoldering iron image by Gudellaphoto from Fotolia.com
  
  Soldering guns have many applications, from repairing home electronic equipment, to fastening together metal components for sculpture or jewelry, to light household and plumbing repair. The key to successful use of a soldering gun, and a successful resulting soldered joint, is good preparation. With the appropriate preparation, even a beginner can use a soldering gun to create a lasting soldered joint.
  
  

Preparation

• The most important step in soldering is preparing the metal surfaces to be joined. If the metal is contaminated with dirt, dust, corrosion, rust or oils, the solder will not be able to form a clean bond with the metal. Prepare any metal pieces to be soldered with a thorough cleaning. Sand the metal pieces until the metal is bright, or use an emery cloth on lengths of tubing. Take care to remove any burrs or ridges that may remain on recently cut pieces using a de-burring tool or a reamer. For soldering jewelry, soak the hand-cleaned pieces in a pickling solution (available at jewelry supply shops), and remove with tongs. In general, do not handle cleaned metal pieces with your bare hands. The naturally occurring oils on your fingers will contaminate the metal, even if your hands appear clean to the naked eye. These oils can interfere with the bonding powers of the solder. The final step in soldering preparation is the application of a thin coat of liquid flux, available at hobby shops, hardware stores, jewelry supply shops or welding supply shops. Flux improves the flow of solder. As the flux burns off during the soldering process, it also removes any remaining oxidation from the metal surfaces.
  
  

Soldering

• Once the metal pieces have been properly cleaned and prepared, clamp or tack them securely together so that they cannot shift during the soldering process. Heat a small amount of solder in the tip of the soldering gun (a process known as "tinning" the soldering iron or gun). When the solder has softened, gently paint it into the joint area with the tip of the gun, adding just a little solder at a time. One of the most common soldering mistakes is to add too much solder at this stage; add just enough solder to span the joint area between the pieces of metal. Adding too much solder will result in a weaker joint.
  
  

Heat

• If you are soldering delicate electronic components, you may not be able to use an additional heat source to complete your soldering job. However, in most other applications, it is best to heat the metal pieces directly in order to cause the solder to "flash," or change color, and flow into the joint area via capillary action. Heating solder with a torch significantly raises the temperature of the solder, and causes it to bond more completely with the surrounding metal. For most home soldering projects, a butane or propane torch will be sufficient. Direct the tip of the torch's flame toward the metal pieces themselves, not toward the joint area or the solder. Move the flame back and forth until the solder melts and flows into the joint.