Soldering iron

Last updated
Electric soldering iron Soldering gun.jpg
Electric soldering iron
A gas-fired soldering iron Gas soldering iron.jpeg
A gas-fired soldering iron

A soldering iron is a hand tool used in soldering. It supplies heat to melt solder so that it can flow into the joint between two workpieces.

Contents

A soldering iron is composed of a heated metal tip (the bit) and an insulated handle. Heating is often achieved electrically, by passing an electric current (supplied through an electrical cord or battery cables) through a resistive heating element. Cordless irons can be heated by combustion of gas stored in a small tank, often using a catalytic heater rather than a flame. Simple irons, less commonly used today than in the past, were simply a large copper bit on a handle, heated in a flame.

Solder melts at approximately 185 °C (365 °F). Soldering irons are designed to reach a temperature range of 200 to 480 °C (392 to 896 °F). [1]

Soldering irons are most often used for installation, repairs, and limited production work in electronics assembly. High-volume production lines use other soldering methods. [2] Large irons may be used for soldering joints in sheet metal objects. Less common uses include pyrography (burning designs into wood) and plastic welding (as an alternative to ultrasonic welding).

History

Historical soldering irons (front) and torches (back) Benzinlotlampen und Lotkolben.jpg
Historical soldering irons (front) and torches (back)

Before the development of electric soldering irons, the typical soldering iron consisted of a copper block, with an appropriately shaped point, supported on an iron rod and held in a wood handle. Immediately before use, the iron was heated over a fire or in a charcoal brazier, and it had to be reheated whenever it became too cool for use. Soldering irons were primarily used by tinsmiths and coppersmiths to work with thin sheet metal. [3]

A large copper block was required in order to have sufficient thermal capacity to provide useful heat after removal from the fire, and copper is expensive. This led to the development of soldering irons that had a small copper tip attached to an inexpensive cast-iron block. [4] Some irons even had removable and replaceable copper tips. [5]

The first electric soldering iron had a very lightweight platinum tip heated by electric current flowing through the tip itself. [6] By 1889, electric soldering irons were being developed with a resistance wire wrapped around the back end of the copper head and enclosed in a protective shell. [7] Alternatively, the heating element could be enclosed in a relatively light-weight hollow copper head. [8]

In 1894, the American Electrical Heater Company began manufacturing electrical soldering irons on a large scale in Detroit. They started producing them and shortly after American Electrical Heater Company released their line of soldering irons. In 1905, Scientific American Magazine, published a tutorial on making a soldering iron that clearly explains how early irons were made. [9]

In 1921, a German company founded by Ernst Sachs developed an electrical soldering iron similar to American Electrical Heater Company iron. in 1926, William Alferink applied for a patent for the first soldering station. [10] [11]

Actual "Form factor" of soldering irons

Electric soldering iron for electronic work Electric soldering iron.jpg
Electric soldering iron for electronic work

In 1946, Carl E. Weller applied for a patent for his soldering gun that could heat instantaneously and began production of the "Speedy Iron" in Pennsylvania. [12] It was manufactured through the Weller Manufacturing Company, and this product was the first instantaneous thermal soldering gun. Few years later, they released to the market a soldering iron on with self-adjusting temperature. In 1951, the company WEN Products began manufacturing its own instantaneous soldering iron. After a three years trial Weller won for patent infringement. [11]

In 1960 Weller got the patent for the soldering iron "Magnastat", renewed in 1964 and 1971. [13] This iron could control the temperature by using a temperature-sensitive magnetic tip. The "Magnastat" became a best seller and it was included it in the W-TCP soldering station in 1967. In fact, within the patent, as a complementary description, it defines what today has become the "de facto", the redundancy is worth it, "form factor" of the vast majority of current Chinese and Japanese irons: Hako, Baku, etc... The now-expired patent, which even Weller has stopped using on some models, described an outer tube holding the coated copper tip, clamped with a nut to the handle. [14]

Located at the remote rear end of draw tube 26, and held thereto by peripheral flange 27, is a freely rotatable threaded nut 28 adapted to be threaded about nut receiving stud 29 of cover flange 21 to draw the tip 11 into proper engagement

Types

Soldering iron in use Soldering-PCB-b.jpg
Soldering iron in use

Simple iron

For electrical and electronics work, a low-power iron, a power rating between 15 and 35  watts, is used. Higher ratings are available, but do not run at higher temperature; instead there is more heat available for making soldered connections to things with large thermal capacity, for example, a metal chassis. [15] Some irons are temperature-controlled, running at a fixed temperature in the same way as a soldering station, with higher power available for joints with large heat capacity. Simple irons run at an uncontrolled temperature determined by thermal equilibrium; when heating something large their temperature drops.

A variation is the Scope soldering iron, common in Australia, which operates from a low-voltage source such as transformer or battery, and heats in seconds when the user pushes the thumb-guard, which then acts as a heat controller.

Cordless iron

Small irons heated by a battery, or by combustion of a gas such as butane in a small self-contained tank, can be used when electricity is unavailable or cordless operation is required. The operating temperature of these irons is not regulated directly; gas irons may change power by adjusting gas flow. Gas-powered irons may have interchangeable tips including different size soldering tips, hot knife for cutting plastics, miniature blow-torch with a hot flame, and small hot air blower for such applications as shrinking heat shrink tubing.

Temperature-controlled soldering iron

Section of a soldering iron tip with an internal heating element Ersadur.svg
Section of a soldering iron tip with an internal heating element

Simple soldering irons reach a temperature determined by thermal equilibrium, dependent upon power input and cooling by the environment and the materials it comes into contact with. The iron temperature will drop when in contact with a large mass of metal such as a chassis; a small iron will lose too much temperature to solder a large connection. More advanced irons for use in electronics have a mechanism with a temperature sensor and method of temperature control to keep the tip temperature steady; more power is available if a connection is large. Temperature-controlled irons may be free-standing, or may comprise a head with heating element and tip, controlled by a base called a soldering station, with control circuitry and temperature adjustment and sometimes display.

A variety of means are used to control temperature. The simplest of these is a variable power control, much like a light dimmer, which changes the equilibrium temperature of the iron without automatically measuring or regulating the temperature. Another type of system uses a thermostat, often inside the iron's tip, which automatically switches power on and off to the element. A thermal sensor such as a thermocouple may be used in conjunction with circuitry to monitor the temperature of the tip and adjust power delivered to the heating element to maintain a desired temperature. [15] [16] In some models, the firmware for the control circuitry is free software that can be modified by the end-user. [17] [18] [19]

Another approach is to use magnetized soldering tips which lose their magnetic properties at a specific temperature, the Curie point. As long as the tip is magnetic, it closes a switch to supply power to the heating element. When it exceeds the design temperature it opens the contacts, cooling until the temperature drops enough to restore magnetisation. More complex Curie-point 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. [20]

Soldering station

Temperature-controlled soldering station Soldering Station Weller 2.jpeg
Temperature-controlled soldering station

A soldering station has a temperature control and consists of an electrical power supply, control circuitry with provision for user adjustment of temperature and display, and a soldering iron or soldering head with a tip temperature sensor. The station will normally have a stand for the hot iron when not in use, and a wet sponge for cleaning. It is most commonly used for soldering electronic components. Other functions may be combined; for example a rework station, mainly for surface-mount components may have a hot air gun, vacuum pickup tool, and a soldering head; a desoldering station will have a desoldering head with vacuum pump for desoldering through-hole components, and a soldering iron head.

Soldering tweezers

Soldering tweezers in use Soldering a 0805.jpg
Soldering tweezers in use
Soldering iron stand Soldering iron in holder.jpg
Soldering iron stand

For soldering and desoldering small surface-mount components with two terminals, such as some links, resistors, capacitors, and diodes, soldering tweezers can be used; they can be either free-standing or controlled from a soldering station. The tweezers have two heated tips mounted on arms whose separation can be manually varied by squeezing gently against spring force, like simple tweezers; the tips are applied to the two ends of the component. The main purpose of the soldering tweezers is to melt solder in the correct place; components are usually moved by simple tweezers or vacuum pickup.

Hot knife

A hot knife is a form of soldering iron equipped with a double-edged blade that is situated on a heating element. These tools can reach temperatures of up to 1,000 degrees Fahrenheit (538 degrees Celsius) allowing for cuts of fabric and foam materials without worry of fraying or beading. Hot knives can be utilized in automotive, marine, and carpeting applications, as well as other industrial and personal uses. [21]

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 common soldering iron tips (also known as soldering bits). Note that there are different tip style naming conventions from manufacturer to manufacturer. Some very typical names are listed here. Common-soldering-tip-styles.png
Some common soldering iron tips (also known as soldering bits). Note that there are different tip style naming conventions from manufacturer to manufacturer. Some very typical names are listed here.
Used plated tip with remains of solder flux Loetspitze IMGP9290.jpg
Used plated tip with remains of solder flux

Most soldering irons for electronics have interchangeable tips, also known as bits, that vary in size and shape for different types of work. [22] [23] [15] Common tip shapes include: bevel, chisel, [24] [25] and conical. [24] [25] An example of a more specialist tip is spoon or gull wing, which features concavity. See the image for renderings of a few different tip shapes and some of the names given to them.

Pyramid tips with a triangular flat face and chisel tips with a wide flat face are useful for soldering sheet metal. Fine conical or tapered chisel tips are typically used for electronics work. Tips may be straight or have a bend. Concave or wicking tips with a chisel face with a concave well in the flat face to hold a small amount of solder are available. [26] [27] Tip selection depends upon the type of work and access to the joint; soldering of 0.5mm pitch surface-mount ICs, for example, is quite different from soldering a through-hole connection to a large area. A concave tip well is said to help prevent bridging of closely spaced leads; different shapes are recommended to correct bridging that has occurred. [28] Due to patent restrictions not all manufacturers offer concave tips everywhere; in particular there are restrictions in the USA. [28]

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

Iron-plated tips may feature a layer of nickel between the copper core and the iron surface. [22] A nickel-chrome outer plating may be used further back from the very tip, as solder does not stick well to this material: this avoids solder wetting parts of the tip where it would be unwanted. [22]

Some tips have a heater and a thermocouple-based temperature sensor embedded to facilitate a more precise temperature control (TS100 and T12, for instance).

Cleaning

Spool of solder. 1.6mm. Solder on spool.jpeg
Spool of solder. 1.6mm.

When the iron tip oxidises and burnt flux accumulates on it, solder no longer wets the tip, impeding heat transfer and making soldering difficult or impossible; tips must be periodically cleaned in use. Such problems happen with all kinds of solder, but are much more severe with the lead-free solders which have become widespread in electronics work, which require higher temperatures than solders containing lead. Exposed iron plating oxidises; if the tip is kept tinned with molten solder oxidation is inhibited. A clean unoxidised tip is tinned by applying a little solder and flux.

A wet small sponge, often supplied with soldering equipment, can be used to wipe the tip. For lead-free solder a slightly more aggressive cleaning, with brass shavings, can be used. Soldering flux will help to remove oxide; the more active the flux the better the cleaning, although acidic flux used on circuit boards that is not carefully cleaned off will cause corrosion. A tip which is cleaned but not retinned is susceptible to oxidation.

Soldering iron tips are made of a copper core plated various metals including iron. The copper is used for heat transfer and the other platings are for durability. Copper is very easily corroded, eating away the tip, particularly in lead-free work; iron is not. Cleaning tips requires the removal of oxide without damaging the iron plating and exposing the copper to rapid corrosion. The use of solder already containing a small amount of copper can slow corrosion of copper tips.

In cases of severe oxidation not removable by gentler methods, abrasion with something hard enough to remove oxide but not so hard as to scratch the iron plating can be used. A brass wire scourer, brush, or wheel on a bench grinder, can be used with care. Sandpaper and other tools may be used but are likely to damage the plating.

Electro-static discharge

Not all soldering irons are ESD-safe.

Although some manufacturers' mains-powered models are built with the element shaft (and hence the tip) electrically connected to ground via the iron's mains lead, [29] other models' tips may float at arbitrary voltages unless an additional grounding wire is used. [17]

See also

Related Research Articles

<span class="mw-page-title-main">Solder</span> Alloy used to join metal pieces

Solder is a fusible metal alloy used to create a permanent bond between metal workpieces. Solder is melted in order to wet the parts of the joint, where it adheres to and connects the pieces after cooling. Metals or alloys suitable for use as solder should have a lower melting point than the pieces to be joined. The solder should also be resistant to oxidative and corrosive effects that would degrade the joint over time. Solder used in making electrical connections also needs to have favorable electrical characteristics.

<span class="mw-page-title-main">Surface-mount technology</span> Method for producing electronic circuits

Surface-mount technology (SMT), originally called planar mounting, is a method in which the electrical components are mounted directly onto the surface of a printed circuit board (PCB). An electrical component mounted in this manner is referred to as a surface-mount device (SMD). In industry, this approach has largely replaced the through-hole technology construction method of fitting components, in large part because SMT allows for increased manufacturing automation which reduces cost and improves quality. It also allows for more components to fit on a given area of substrate. Both technologies can be used on the same board, with the through-hole technology often used for components not suitable for surface mounting such as large transformers and heat-sinked power semiconductors.

<span class="mw-page-title-main">Brazing</span> Metal-joining technique

Brazing is a metal-joining process in which two or more metal items are joined by melting and flowing a filler metal into the joint, with the filler metal having a lower melting point than the adjoining metal.

<span class="mw-page-title-main">Clothes iron</span> Tool or appliance for smoothing cloth using heat and pressure

A clothes iron is a small appliance that, when heated, is used to press clothes to remove wrinkles and unwanted creases. Domestic irons generally range in operating temperature from between 121 °C (250 °F) to 182 °C (360 °F). It is named for the metal (iron) of which the device was historically made, and the use of it is generally called ironing, the final step in the process of laundering clothes.

<span class="mw-page-title-main">Water heating</span> Thermodynamic process that uses energy sources to heat water

Water heating is a heat transfer process that uses an energy source to heat water above its initial temperature. Typical domestic uses of hot water include cooking, cleaning, bathing, and space heating. In industry, hot water and water heated to steam have many uses.

Forge welding (FOW), also called fire welding, is a solid-state welding process that joins two pieces of metal by heating them to a high temperature and then hammering them together. It may also consist of heating and forcing the metals together with presses or other means, creating enough pressure to cause plastic deformation at the weld surfaces. The process, although challenging, has been a method of joining metals used since ancient times and is a staple of traditional blacksmithing. Forge welding is versatile, being able to join a host of similar and dissimilar metals. With the invention of electrical welding and gas welding methods during the Industrial Revolution, manual forge-welding has been largely replaced, although automated forge-welding is a common manufacturing process.

<span class="mw-page-title-main">Desoldering</span> Removal of solder and components from a circuit board

In electronics, desoldering is the removal of solder and components from a circuit board for troubleshooting, repair, replacement, and salvage.

<span class="mw-page-title-main">Hot plate</span> Portable self-contained tabletop small appliance

A hot plate or hotplate is a portable self-contained tabletop small appliance cooktop that features one or more electric heating elements or gas burners. A hot plate can be used as a stand-alone appliance, but is often used as a substitute for one of the burners from an oven range or a kitchen stove. Hot plates are often used for food preparation, generally in locations where a full kitchen stove would not be convenient or practical. They can also be used as a heat source in laboratories. A hot plate can have a flat surface or round surface. Hot plates can be used for traveling or in areas without electricity.

<span class="mw-page-title-main">Heating element</span> Device that converts electricity into heat

A heating element is a device used for conversion of electric energy into heat, consisting of a heating resistor and accessories. Heat is generated by the passage of electric current through a resistor through a process known as Joule Heating. Heating elements are used in household appliances, industrial equipment, and scientific instruments enabling them to perform tasks such as cooking, warming, or maintaining specific temperatures higher than the ambient.

<span class="mw-page-title-main">Rework (electronics)</span> Refinishing operation of an electronic printed circuit board assembly

In electronics, rework is the repair or refinish of a printed circuit board (PCB) assembly, usually involving desoldering and re-soldering of surface-mounted electronic components (SMD). Mass processing techniques are not applicable to single device repair or replacement, and specialized manual techniques by expert personnel using appropriate equipment are required to replace defective components; area array packages such as ball grid array (BGA) devices particularly require expertise and appropriate tools. A hot air gun or hot air station is used to heat devices and melt solder, and specialised tools are used to pick up and position often tiny components. A rework station is a place to do this work—the tools and supplies for this work, typically on a workbench. Other kinds of rework require other tools.

<span class="mw-page-title-main">ColdHeat</span> American company

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 time.

<span class="mw-page-title-main">Soldering gun</span>

A soldering gun is an approximately pistol-shaped, electrically powered tool for soldering metals using tin-based solder to achieve a strong mechanical bond with good electrical contact. The tool has a trigger-style switch so it can be easily operated with one hand. The body of the tool contains a transformer with a primary winding connected to mains electricity when the trigger is pressed, and a single-turn secondary winding of thick copper with very low resistance. A soldering tip, made of a loop of thinner copper wire, is secured to the end of the transformer secondary by screws, completing the secondary circuit. When the primary of the transformer is energized, several hundred amperes of current flow through the secondary and very rapidly heat the copper tip. Since the tip has a much higher resistance than the rest of the tubular copper winding, the tip gets very hot while the remainder of the secondary warms at a much slower rate. An additional secondary winding is often used to power a pilot lamp which illuminates the workpiece.

<span class="mw-page-title-main">Heat gun</span> Power tool used to emit hot air

A heat gun is a device used to emit a stream of hot air, usually at temperatures between 100 and 550 °C, with some hotter models running around 760 °C, which can be held by hand. Heat guns usually have the form of an elongated body pointing at what is to be heated, with a handle fixed to it at right angles and a pistol grip trigger in the same pistol form factor as many other power tools.

<span class="mw-page-title-main">Hot cathode</span> Type of electrode

In vacuum tubes and gas-filled tubes, a hot cathode or thermionic cathode is a cathode electrode which is heated to make it emit electrons due to thermionic emission. This is in contrast to a cold cathode, which does not have a heating element. The heating element is usually an electrical filament heated by a separate electric current passing through it. Hot cathodes typically achieve much higher power density than cold cathodes, emitting significantly more electrons from the same surface area. Cold cathodes rely on field electron emission or secondary electron emission from positive ion bombardment, and do not require heating. There are two types of hot cathode. In a directly heated cathode, the filament is the cathode and emits the electrons. In an indirectly heated cathode, the filament or heater heats a separate metal cathode electrode which emits the electrons.

<span class="mw-page-title-main">Electric heating</span> Process in which electrical energy is converted to heat

Electric heating is a process in which electrical energy is converted directly to heat energy. Common applications include space heating, cooking, water heating and industrial processes. An electric heater is an electrical device that converts an electric current into heat. The heating element inside every electric heater is an electrical resistor, and works on the principle of Joule heating: an electric current passing through a resistor will convert that electrical energy into heat energy. Most modern electric heating devices use nichrome wire as the active element; the heating element, depicted on the right, uses nichrome wire supported by ceramic insulators.

<span class="mw-page-title-main">Fan heater</span> Heat producing machine to increase temperature of an enclosed space

A fan heater, also called a blow heater, is a heater that works by using a fan to pass air over a heat source. This heats up the air, which then leaves the heater, warming up the surrounding room. They can heat an enclosed space such as a room faster than a heater without a fan, but like any fan, create a degree of noise.

<span class="mw-page-title-main">Dip soldering</span> Solder by immersion in a bath of molten solder

Dip soldering is a small-scale soldering process by which electronic components are soldered to a printed circuit board (PCB) to form an electronic assembly. The solder wets to the exposed metallic areas of the board, creating a reliable mechanical and electrical connection.

<span class="mw-page-title-main">Soldering station</span>

A soldering station is a multipurpose power soldering device designed for electronic components soldering. This type of equipment is mostly used in electronics and electrical engineering. Soldering station consists of one or more soldering tools connected to the main unit, which includes the controls, means of indication, and may be equipped with an electric transformer. Soldering stations may include some accessories – holders and stands, soldering tip cleaners, etc.

<span class="mw-page-title-main">Soldering</span> Process of joining metal pieces with heated filler metal

Soldering is a process of joining two metal surfaces together using a filler metal called solder. The soldering process involves heating the surfaces to be joined and melting the solder, which is then allowed to cool and solidify, creating a strong and durable joint.

<span class="mw-page-title-main">Scope soldering iron</span> Tool for soldering with lead-tin alloys

The "Scope" soldering iron is a tool for soldering with lead-tin alloys, made in Australia since 1950, and intended for occasional or intermittent use. It has the virtue of quickly coming up to soldering temperature (~300C) and delivering considerable heat to a small area, but requires care to avoid overheating. It operates on low voltage and high current from a battery or suitable transformer, so is by design electrically safe, and as it cools down rapidly when it leaves the operator's hand, should not constitute a fire risk.

References

  1. "Lower-Melting-Point Solder Alloy". tms.org. 1997-02-07. Archived from the original on 2020-09-21. Retrieved 2023-09-07.
  2. Bralla, James G. Handbook of Manufacturing Processes - How Products, Components and Materials are Made Industrial Press, 2007 page 297
  3. C. Tomlinson, Ed., Solder, Cyclopædia of useful arts & manufactures, Vol. 7, George Virtue, London, 1852; pages 662-666, page 664 discusses soldering irons.
  4. John H. Trowbridge, Improvement in Soldering-Irons, U.S. patent 53,545 , granted Mar. 27, 1866.
  5. Lester Patee, Improvement in Soldering-Irons, U.S. patent 29,039 , granted July 3, 1860.
  6. Charles E. Ball, Soldering Iron, U.S. patent 236,972 , granted Jan. 25, 1881.
  7. Willard M. Miner, Electric Soldering-Iron, U.S. patent 421,185 , granted Feb. 11, 1890.
  8. Arthur E. Appleyard, Electric Soldering-Iron, U.S. patent 455,010 , June 30, 1891.
  9. Arthur Weeks, How to Make an Electric Soldering Iron, Scientific American Vol. XCII, No. 14 (Apr. 8, 1905); page 283.
  10. William Alferink, Combined Holder and Automatic Circuit Breaker for Electric Soldering Irons, U.S. patent 1,675,401 , July 3, 1928.
  11. 1 2 "History 101 - The Modern Soldering Iron". November 29, 2018.
  12. Carl E. Weller, Electrically Heated Apparatus, U.S. patent 2,593,947 , April 22, 1952.
  13. "US3662152A - Thermomagnetic soldering tip assembly and method". Google Patents. 1971-03-05. Retrieved 2023-09-08.
  14. "US3287541A - Temperature controlled soldering iron". Google Patents. 1964-07-13. Retrieved 2023-09-08.
  15. 1 2 3 Winstanley, Alan, The Basic Soldering Guide, archived from the original on 2010-01-18, retrieved 2010-04-14.
  16. "What is the TS100 Soldering Iron?".
  17. 1 2 "Review: TS100 Soldering Iron". 24 July 2017.
  18. "Tetris on a Soldering Iron". 7 July 2017.
  19. "Play the Tiniest Version of 'Tetris' on a Soldering Iron". 7 July 2017.
  20. "Thermaltronics Soldering: Products > TMT-9000S Soldering and Rework Station". Thermaltronics.com. Retrieved 27 August 2018.
  21. "What is a Hot Knife? - MM Newman Corporate". MM Newman Corporation. 19 August 2013. Retrieved 2016-01-14.
  22. 1 2 3 "Soldering Tips" (PDF). Userwww.sfsu.edu. Retrieved 27 August 2018.
  23. "Archived copy". Archived from the original on 2015-05-26. Retrieved 2018-12-01.{{cite web}}: CS1 maint: archived copy as title (link)
  24. 1 2 "Understanding Different Soldering Iron Tips - Make". Makezine.com. Retrieved 27 August 2018.
  25. 1 2 "How to Solder: Through-Hole Soldering". Learn.sparkfun.com. Retrieved 27 August 2018.
  26. "Hakko FX-888 Tips - Page 1". Eevblog.com. Retrieved 27 August 2018.
  27. "Soldering Tip Series 832". Ersa.com. Retrieved 27 August 2018.
  28. 1 2 "HAKKO - Select Tip Shape - Drag soldering". Hakko.com. Retrieved 27 August 2018.
  29. "FAQ's". Antex (Electronics) Limited. Retrieved 2018-08-28. [It] is appropriate to routinely test mains powered irons and stations... Guidance values for the tester settings [include:] Earth Bond Test ... pass result: < 0.1 Ohm ... A higher reading (i.e. up to 0.5 Ohm) can still be regarded as safe because the earth connection from the plug to the element shaft is welded or soldered throughout...