Soldering iron is tool used in soldering process for generating heat. Soldering irons come in a wide variety of shapes, sizes and wattages. A soldering iron is composed of a heater block and an insulated handle. Iron’s handle is made from thick plastic and usually have additional foam layer that reduces heat transfer from the iron into your hand. Heating is often achieved electrically, by passing a current, supplied through an electrical cord or a battery, through a heating element.
The heater block is a source of heat. Simple heater block consists basically of the heater element and the tip (or bit). The iron tip transfers heat from heater element to the soldering joint. Resulting tip temperature depends on the capacity of the heater, and mass of the iron tip.
Iron tips are made of a copper core enclosed by iron, because solder does not stick to nickel or chrome but sticks to iron. A new tip needs to be coated, heated, and then covered with solder before its first use. This procedure is called "tinning" and its purpose is to form a thin layer around the tip which provides the better transfer of heat from the tip to the solder joint. Only clean tip transfers heat well. During soldering work the tip needs to be kept coated with a thin layer of solder by occasional wiping the tip on dump sponge to clean it and then applying a small amount of solder directly to the tip.
Temperature controlled soldering irons have capability of controlling and adjusting the temperature of the iron tip. That means that operator can set desired temperature of the tip with knob located on front panel of soldering station.
There are mainly three different versions of temperature controlled soldering iron. In first version, operator can increase or decrease the voltage across the heater and therefore change the temperature of the iron tip (basic soldering irons have constant voltage applied to heater without possibility to vary it). In second version, temperature of iron tip can be set with temperature controlled magnetic switch within the heater block. Here we have a small magnet which has been designed to lose its magnetic properties at certain temperature. This magnet forms part of the switch within the heater assembly, and when magnet lose magnetic properties (at certain temperature) as result, the switch opens and cuts off the voltage to heater. Third version of temperature controlled soldering iron is a soldering iron that contains a temperature sensor built within the heater assembly. Operator set the desired temperature for his soldering project and then the temperature sensor within heater assembly, through feedback system, turns on and off the heater element to maintain temperature at desired level.
Temperature controlled irons should be used whenever we have to solder temperature-sensitive components There are many soldering stations which are capable to accurately maintain temperature at desired level – for example on WESD51 Weller soldering iron you can precisely control the temperature of iron within 9 degrees Fahrenheit.
