SHOP PRACTICES

Step one is to have the proper soldering iron, solder and technique. The soldering iron's tip size and wattage should match the size of the job. If you are working on printed circuit boards a 25 watt pencil sized iron is appropriate with tips 1/8th inch or smaller. Cordless irons work well here and may be less likely to induce unwanted voltages. Bench-top thermostatically controlled irons can be ideal for most work. The temperature of the iron should be adjusted just high enough to heat the part being solder to just above the melting point of the solder. This is usually around 360 degrees F. The tip temperature will need to be somewhere around 460 to heat the part sufficiently and melt the solder. You must also consider the problems of static discharges with any iron if you are working on circuits with installed sensitive integrated circuits or field effect transistors. You may also need to use a heat sink to protect installed parts from excessive heat. Alligator clips or heat sink clamps will help. The main purpose of the iron is to heat the part being soldered to just high enough temperature to melt the solder. The solder (60/40 tin/lead of .025 to .040 inches in diameter) is place on the part being soldered not the iron. Although briefly touching the solder to the iron tip prior to the actual soldering can be helpful in transferring the irons heat to the part. Avoid touching the solder to the iron when soldering; touch the solder to the part. This is insurance against a cold solder joint which is to be avoided. A cold solder joint is one where the part was not hot enough to melt the solder and results in a poor connection. Normally the use of a rosin core solder is sufficient for most soldering jobs. Occasionally for larger work adding a separate soldering rosin paste may facilitate a better job. For larger work a handheld soldering gun is appropriate. Even larger work such as copper water pipes will require the use of a propane torch. For copper water pipes be sure the solder contains no lead. The larger the job the larger diameter solders are appropriate. Regardless of the size of the project the basic principles are the same. The finished soldering job should be smooth and shiny, not dull. On new printed circuit boards it is often helpful to apply a tin coating to the copper runs to insure all the connections are of low resistance and avoid later problems due to corrosion. Click>> for BASIC SOLDERING GUIDE.
SOLDERING