Soldering gun
A soldering gun is a tool
A tool is a device that can be used to produce an item or achieve a task, but that is not consumed in the process. Informally the word is also used to describe a procedure or process with a specific purpose. Tools that are used in particular fields or activities may have different designations such...

 for soldering
Soldering is a process in which two or more metal items are joined together by melting and flowing a filler metal into the joint, the filler metal having a lower melting point than the workpiece...

 metals using tin-based solder
Solder is a fusible metal alloy used to join together metal workpieces and having a melting point below that of the workpiece.Soft solder is what is most often thought of when solder or soldering are mentioned and it typically has a melting range of . It is commonly used in electronics and...

 to achieve a highly conductive contact. The tool uses a pistol shape, and has a trigger style switch so it can be easily operated with one hand. The body of the tool contains a transformer with a single-turn secondary element. A soldering tip, made of a loop of copper wire, is secured to the end of the transformer secondary by screws. When the primary of the transformer is energized, the secondary produces a fraction of a volt and several hundred amperes of current, which rapidly heats the copper tip. Since the tip has a much smaller cross section than the rest of the tubular copper winding, most of the heat is produced near the point of use. A tap on the primary winding is often used to light a pilot lamp which also provides illumination of the workpiece.

Applications such as soldering high current load wires, often found in inconvenient locations such as automobile bodies, preclude the use of a soldering station. A constant-heat device has to be set in a safe place when not in use, to prevent damage or fire. The fast switching gun cools quickly enough to be set down just seconds after use.


Soldering guns are used where more heat is needed than from pencil-style soldering irons. They can be used for heavy electrical connections, stained glass
Stained glass
The term stained glass can refer to coloured glass as a material or to works produced from it. Throughout its thousand-year history, the term has been applied almost exclusively to the windows of churches and other significant buildings...

 assembly, and light sheet-metal work. Typical soldering guns are rated between 100 and 240 watts power. A gun may include a two-stage trigger to give two heat settings. Consumer soldering guns are often packaged with accessory tips intended for cutting and shaping plastic.

Soldering guns may be used to solder the small SMD components, after replacing the default thick wire with a thin one. If the wire loop is bent into a rectangular shape, the gun can be used to solder 14- and 16-pin 1.27 mm pitch SMD packages in about 8 seconds by heating all pins at once.

The tip shape, in the form of a wire loop, is advantageous for getting into confined space; the tip can be rotated to get into a gap between neighbouring components. This is not practical with the cone shape of a usual soldering iron. Temperature in the soldering gun is regulated manually by holding the button until the solder melts, and then releasing it. When the solder is about to start solidifying, the button is pressed again, and so on. An experienced worker develops the skill to regulate the temperature according to need.

A disadvantage of a soldering gun is that the copper wire loop slowly dissolves in the solder and has to be regularly replaced. The soldering gun generates an electromagnetic spike when the button is released, which can be a problem for electromagnetically-sensitive devices. The spike can be seen when a high-efficiency LED
LEd is a TeX/LaTeX editing software working under Microsoft Windows. It is a freeware product....

 is soldered, as the LED flashes. Soldering guns produce too much heat for joints on printed circuit board
Printed circuit board
A printed circuit board, or PCB, is used to mechanically support and electrically connect electronic components using conductive pathways, tracks or signal traces etched from copper sheets laminated onto a non-conductive substrate. It is also referred to as printed wiring board or etched wiring...

s. The heavy magnetic field produced by the tip can attract and hold small ferrous metal pieces (screws, etc.).


Pistol-grip electrically-heated soldering tools had been used since the 1920s. In 1941 Carl E. Weller invented and later obtained for a transformer-type soldering tool, which heated up rapidly. Unlike other electrically-heated tools of the time, his soldering gun used a copper heating element, directly heated by a current of hundreds of amperes produced from a small transformer in the body of the gun. The relatively small mass of the copper element heated rapidly and cooled off quickly when the trigger was released. Weller formed a company to manufacture and sell his invention commercially in 1946. The Weller company was bought in 1970 and merged into the Cooper Industries
Cooper Industries
Cooper Industries is a former US-based company that in 2009 switched its incorporation office from Bermuda to Ireland, maintaining its chief operational offices in Houston, Texas. It produces transformers, tools and electrical equipment, employing 29,000 staff around the world. Revenue in 2007 was...

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