Kyle Manhart

Photo II: Electric Soldering Iron The art of soldering is nearly five millennia old, dating back to the beginning of the bronze age. Soldering began around 3000 B.C. in Egypt and spread around the Mediterranean Sea as tin was discovered and became more commonly used. Soldering differs from welding in that the base metals, those being joined, are not melted in the process. Soldering temperatures usually range around 250⁰C and below differing it from brazing which takes place at temperatures over 250⁰C. In 1921 ERSA, a German Company, was the first company to patent an electric soldering iron. The Weller Soldering Iron used in this photo converts 12V of electricity to heat by passing the current through a resistive tip. The resistance in the tip can produce enough heat such that the tip of the iron can reach temperatures of 750⁰C. The tip is replaceable so that a variety of tips can be used depending on the purpose whether it be soldering circuit boards and wires or working on stain class. These are relatively inexpensive and the soldering iron itself only costs ten dollars or so. One improvement would be to have some way of controlling the temperature of the tip. This can be accomplished one of several ways. Some more expensive soldering irons utilize a thermocouple or thermometer to detect temperatures and then utilizing a thermostat to regulate the temperature to a preset threshold. The most interesting is to use a magnet tip. As the tip temperature increases the magnetic field decreases and eventually loses all strength. The tip then slides out until it cools down and is pulled back into contact with the resistive material. This photo was taken utilizing a 6 MP Nikon Cool Pix Camera. The macro setting with a focal length of 12mm was used. A light source over the shoulder was used to produce the shadow above the soldering iron. The exposure time was 1/60 second and the ISO-100 setting. A -1 exposure bias was also implemented to produce a slightly brighter photo since this lighting was quite dark.