Soldering iron
Overview
 
A soldering iron is a hand tool
Hand tool
A hand tool is a device for performing work on a material or a physical system using only hands. The hand tools can be manually used employing force, or electrically powered, using electrical current...

 most commonly used in soldering
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...

. It supplies heat to melt the solder
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...

 so that it can flow into the joint between two workpieces.

A soldering iron is composed of a heated metal tip and an insulated handle. Heating is often achieved electrically, by passing an electric current (supplied through an electrical cord or battery cables) through the resistive material of a heating element
Heating element
A heating element converts electricity into heat through the process of Joule heating. Electric current through the element encounters resistance, resulting in heating of the element....

.
Encyclopedia
A soldering iron is a hand tool
Hand tool
A hand tool is a device for performing work on a material or a physical system using only hands. The hand tools can be manually used employing force, or electrically powered, using electrical current...

 most commonly used in soldering
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...

. It supplies heat to melt the solder
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...

 so that it can flow into the joint between two workpieces.

A soldering iron is composed of a heated metal tip and an insulated handle. Heating is often achieved electrically, by passing an electric current (supplied through an electrical cord or battery cables) through the resistive material of a heating element
Heating element
A heating element converts electricity into heat through the process of Joule heating. Electric current through the element encounters resistance, resulting in heating of the element....

. Another heating method includes combustion of a suitable gas, which can either be delivered through a tank mounted on the iron (flameless), or through an external flame.

Less common uses include pyrography
Pyrography
Pyrography is the art of decorating wood or other materials with burn marks resulting from the controlled application of a heated object such as a poker. It is also known as pokerwork or wood burning....

 (burning designs into wood) and plastic welding
Plastic welding
Plastic welding or heat sealing is the process of welding plastic workpieces together. It is a very common process for joining plastics.-Hot gas welding:...

.

Soldering irons are most often used for installation, repairs, and limited production work. High-volume production lines use other soldering methods.

Electronics

For electrical work, a low-power iron, a power rating between 15 and 30 watt
Watt
The watt is a derived unit of power in the International System of Units , named after the Scottish engineer James Watt . The unit, defined as one joule per second, measures the rate of energy conversion.-Definition:...

s, is used. Higher ratings are available, but do not run hotter; instead there is more power available for larger joints.

Small battery-operated or gas soldering irons are useful when electricity is unavailable.

Temperature-controlled soldering station

A temperature-controlled soldering station consists of an electrical power supply and a soldering iron. It is most commonly used for soldering electronic components.

A variety of means are used to control temperature. The simplest of these is a variable power control, much like a light dimmer, which together with the loss of heat from the iron to the environment roughly sets the temperature. Another type of system uses a thermostat
Thermostat
A thermostat is the component of a control system which regulates the temperature of a system so that the system's temperature is maintained near a desired setpoint temperature. The thermostat does this by switching heating or cooling devices on or off, or regulating the flow of a heat transfer...

, often inside the iron's tip, which switches power on and off to the elements. A more advanced version of this uses a microprocessor
Microprocessor
A microprocessor incorporates the functions of a computer's central processing unit on a single integrated circuit, or at most a few integrated circuits. It is a multipurpose, programmable device that accepts digital data as input, processes it according to instructions stored in its memory, and...

 to monitor the temperature of the tip via a thermocouple
Thermocouple
A thermocouple is a device consisting of two different conductors that produce a voltage proportional to a temperature difference between either end of the pair of conductors. Thermocouples are a widely used type of temperature sensor for measurement and control and can also be used to convert a...

 and adjusts the power to the heating element accordingly.

Another approach is to use magnetized soldering tips which lose their magnetic properties at a certain temperature (the Curie point
Curie point
In physics and materials science, the Curie temperature , or Curie point, is the temperature at which a ferromagnetic or a ferrimagnetic material becomes paramagnetic on heating; the effect is reversible. A magnet will lose its magnetism if heated above the Curie temperature...

). As long as the tip is magnetic, it clings to the heating element. At the design temperature, it loses contact, cooling down. Other complex irons circulate a high-frequency AC current through the tip, using magnetic physics to direct heating only where the surface of the tip drops below the Curie point.

Stands

A soldering iron stand keeps the iron away from flammable materials, and often also comes with a cellulose sponge and flux pot for cleaning the tip. Some soldering irons for continuous and professional use come as part of a soldering station, which allows the exact temperature of the tip to be adjusted, kept constant, and sometimes displayed.

Tips

Some soldering irons have interchangeable tips, also known as bits, that vary in size and shape for different types of work. Pyramid tips with a triangular flat face and chisel tips with a wide flat face are useful for soldering sheet metal
Sheet metal
Sheet metal is simply metal formed into thin and flat pieces. It is one of the fundamental forms used in metalworking, and can be cut and bent into a variety of different shapes. Countless everyday objects are constructed of the material...

. Fine conical or tapered chisel tips are typically used for electronics work.

Older and very cheap irons typically use a bare copper tip, which is shaped with a file or sandpaper. This dissolves gradually into the solder, suffering pitting and erosion of the shape. Copper tips are sometimes filed when worn down. Iron-plated copper tips have become increasingly popular since the 1980s. Because iron is not readily dissolved by molten solder, the plated tip is more durable than a bare copper one. This is especially important when working at the higher temperatures needed for modern lead-free solders. Solid iron and steel tips are seldom used because they store less heat, and rusting can break the heating element.

Cleaning

When burnt flux and oxidized material begin to accumulate on the tip, they can block heat transfer and contaminate joints, making soldering difficult or impossible. Therefore, the tips are periodically cleaned. Many soldering stations come with cellulose sponges which are dampened and used to wipe a hot iron's tip clean. A wire brush, preferably brass or wire wheel (mounted on a bench grinder), is sometimes carefully used to remove very severe oxidation, though this may risk damaging the tip's protective iron plating. A small amount of fresh solder is usually then applied to the clean tip in a process called tinning
Tinning
Tinning is the process of thinly coating sheets of wrought iron or steel with tin, and the resulting product is known as tinplate. It is most often used to prevent rust....

. The working surface of the tip is usually kept tinned (coated with wet solder) to minimize oxidation. Oxidation blocks heat transfer, corrodes the tip, and contaminates the joint.

See also

  • Soldering gun
    Soldering gun
    A soldering gun is a tool for soldering metals using tin-based solder 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...

  • Brazing
    Brazing
    Brazing is a metal-joining process whereby a filler metal is heated above and distributed between two or more close-fitting parts by capillary action. The filler metal is brought slightly above its melting temperature while protected by a suitable atmosphere, usually a flux...

     — Joining metals structurally by the use of a higher temperature joining alloy than solder.
  • Welding
    Welding
    Welding is a fabrication or sculptural process that joins materials, usually metals or thermoplastics, by causing coalescence. This is often done by melting the workpieces and adding a filler material to form a pool of molten material that cools to become a strong joint, with pressure sometimes...

     — Melting two objects to be joined into each other.
  • ColdHeat
    ColdHeat
    ColdHeat was an American company founded to develop and market products using the proprietary graphite-like compound Athalite. The composite material is claimed by the manufacturer to have the unusual ability to conduct large amounts of heat and return to room temperature in a short amount of...

     — A simple "instant heat" soldering iron
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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