Soldering is an easy way to mend metals permanently. When you solder metal, small jobs are best done with an electric soldering iron of the conventional type or of the faster gun type. Larger soldering jobs can be done with a blowtorch. The tips of soldering irons must be kept nice and smooth, clean and coated with a thin layer of solder. Torch tips must also be kept clean and undamaged if they are to give a steady blue flame of proper size and shape. Solder is a mix of tin and lead used to join metallic parts, and is available in the bar, paste and wire forms. Bar solder is solid, while paste solder is mixed with acid flux. And wire solder may be solid solder or may contain a core of rosin flux or acid. Whenever solid solder is used, a flux, which cleans the metal must be applied first to the metal. This comes as a paste or liquid. Rosin flux is used only in making electrical connections and on terne metal while acid flux is used for all other work.
Step-by-step metal soldering
1. Thoroughly clean the object to be soldered. You can use steel wool, a file or emery cloth to clean flat surfaces until it becomes shiney.
2. Scrape any wire to be soldered with the back of a knife or a flat piece of metal.
3. If the wire is extremely dirty, you can dip it into flux to clean it.
4. Heat metal, making sure it is hot enough to melt the solder applied to it. When in the case of lead and pewter, the solder should be melted by the metal being soldered. When the metal is not heated enough, the melted solder will look lifeless and rough. When done properly, what you should see is a smooth bright surface.
5. In order to solder metal pieces, you should tin or flow a film of solder on the pieces separately. You then place surface to surface (one tin surface to the other), then heat until the solder melts. Take away heat, then hold the pieces together. You can do this by applying a gripping device until the solder is hard.
6. When soldering copper pipe into a plumbing fitting, make sure to clean both the pipe and the fitting. Then brush acid flux on it. Next, insert the pipe into the fitting, then apply heat to the joint. Then touch solid solder to the joint.
7. Any time acid flux is used, make sure to wash off the residue thoroughly after it has cooled.
