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IT'S PROUNOUNCED SAW-DER NOT SOLDER GODDAMNIT.

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+IT'S PROUNOUNCED SAW-DER NOT SOLDER GODDAMNIT.
-A '''solder''' is a [[fusible alloy|fusible]] metal [[alloy]] with a melting point or melting range of 90 to 450&nbsp;°[[Celsius|C]] (200 to 840 °[[Fahrenheit|F]]), used in a process called [[soldering]] where it is melted to join metallic surfaces. It is especially useful in [[electronics]] and [[plumbing]]. Alloys that melt between 180 and 190&nbsp;°C are the most commonly used.
-The word solder comes from the [[Middle English]] word ''soudur'', via [[Old French]] ''solduree'' and ''soulder'', from the [[Latin]] ''solidare'', meaning '‘to make solid’'. In North [[American English]] "solder" is pronounced with a short ''O'' and silent ''L'' whereas in [[British English]] the word is pronounced as written. Solder can contain lead and or flux but in many applications solder is now lead free.
-[[Image:Desoldering.jpg|thumb|right|Desoldering a contact and a wire attached with solder.]]
-==Lead solder==
-[[Tin]]/[[lead]] solders are commercially available with tin concentrations between 5% and 70% by weight. The greater the tin concentration, the greater the solder’s [[Tensile strength|tensile]] and [[shear strength]]s. At the retail level, the two most common alloys are 60/40&nbsp;[[Tin|Sn]]/[[Lead|Pb]] and 63/37&nbsp;Sn/Pb used principally in electrical work. The 63/37 ratio is notable in that it is a [[Eutectic point|eutectic]] mixture, which means:
-# It has the lowest melting point (183&nbsp;°C or 361.4&nbsp;°F) of all the tin/lead alloys; and
-# The melting point is truly a ''point'' — not a range
-At an eutectic composition, the liquid solder solidifies as a eutectic, which consists of fine grains of nearly pure lead and nearly pure tin phases, but in no way is it an intermetallic, since there are no tin/lead intermetallics, as can be seen from a tin/lead equilibrium diagram. [http://pwatlas.mt.umist.ac.uk/internetmicroscope/micrographs/microstructures/more-metals/lead.html]
-In plumbing, a higher proportion of lead was used. This had the advantage of making the alloy solidify more slowly, so that it could be wiped over the joint to ensure watertightness. Although lead water pipes were displaced by copper when the significance of [[lead poisoning]] began to be fully appreciated, lead solder was still used until the 1980s because it was thought that the amount of lead that could leach into water from the solder was negligible. Since even small amounts of lead have been found detrimental to health, lead in plumbing solder was replaced by [[copper]] or [[antimony]], with [[silver]] often added, and the proportion of tin was increased (see ''[[#Lead-free_solder|Lead-free solder]]'' below).
-Solder is made up of tin (30%) and lead (70%). It can bond metals together as it has a fairly low melting point of 183 Degrees Celcius.
-==Hard solder==
-As used for [[brazing]], is generally a copper/[[zinc]] or copper/silver alloy, and melts at higher temperatures.
-In silversmithing or jewelry making, special hard solders are used that will pass [[assay]].  They contain a high proportion of the metal being soldered and lead is not used in these alloys.  These solders also come in a variety of hardnesses, known as 'enamelling', 'hard', 'medium' and 'easy'.  [[Vitreous enamel|Enamelling]]  solder has a high melting point, close to that of the material itself, to prevent the joint [[desoldering]] during firing in the enamelling process.  The remaining solder types are used in decreasing order of hardness during the process of making an item, to prevent a previously soldered seam or joint desoldering while soldering a new joint.  Easy solder is also often used for repair work for the same reason.  [[Flux (metallurgy)|Flux]] or rouge is also used to prevent joints desoldering.
-Silver solder is also used in manufacturing, when there is a need to join metal parts that cannot be [[welding|welded]]. The alloys used for these purposes contain a high proportion of silver (up to 40%), and may also contain toxic [[cadmium]].
-==Flux core solder==
-[[Image:Ersin Multicore Solder Tube.jpg|thumb|right|A tube of multicore electronics solder used for manual soldering - the flux is contained in five cores within the solder itself]]
-Solder often comes pre-mixed with, or is used with, [[Flux (metallurgy)|flux]], a reducing agent designed to help remove impurities (specifically [[oxidation|oxidised]] metals) from the points of contact to improve the electrical connection.  For convenience, solder is often manufactured as a hollow tube and filled with flux. Most cold solder is soft enough to be rolled and packaged as a coil, making for a convenient and compact solder/flux package.  The two principal types of flux are acid flux, used for metal mending, and [[rosin]] flux, used in electronics, where the corrosiveness of the vapours that arise when acid flux is heated could damage components.  Due to concerns over atmospheric pollution and hazardous waste disposal, the electronics industry has been gradually shifting from rosin flux to water-soluble flux, which can be removed with [[deionised water]] and detergent, instead of hydrocarbon solvents.
-==Lead-free solder==<!-- NOTE TO EDITORS: This section is internally linked from the "Lead solder"-section of this article.]] -->
-[[Image:Ex Lead freesolder.jpg|left|thumb|A coil of lead-free solder wire]]
-On [[July 1]] [[2006]] the [[European Union]] [[Waste Electrical and Electronic Equipment Directive]] (WEEE) and [[Restriction of Hazardous Substances Directive]] (RoHS) came into effect prohibiting the intentional addition of lead to most consumer electronics produced in the EU.  No such legislation is in place in the United States or other countries, however manufacturers may receive tax benefits by reducing the use of lead-based solder. Lead-free solders in commercial use may contain tin, copper, silver, [[bismuth]], [[indium]], [[zinc]], [[antimony]], and traces of other metals.  Most lead-free replacements for conventional Sn60/Pb40 and Sn63/Pb37 solder have melting points from 5–20&nbsp;°C higher, though solders with much lower melting points are available.
-Drop-in replacements for silkscreen with solder paste soldering operations are available.  Minor modification to the solder pots (e.g. titanium liners and/or impellers) used in wave-soldering operations may be desired to reduce maintenance costs associated with the increased tin-scavenging effects of high tin solders.  The properties of lead-free solders are not as thoroughly known and may therefore be considered less reliable in select applications, e.g. Hi-rel aerospace and life-critical medical. "[[Whisker (metallurgy)|Tin whiskers]]" were a problem with early electronic solders which were coincidentally lead-free, and lead was initially added in part to eliminate them.  These problems are negligible in modern alloys,{{Fact|date=June 2008}} however, except in hi-rel military, aerospace-satellite and life-critical medical applications.
-* SnAgCu solders are used by two thirds of Japanese manufacturers for reflow and [[wave soldering]], and by about ¾ companies for hand soldering.
-** SnAg<sub>3.0</sub>Cu<sub>0.5</sub>, tin with 3% silver and 0.5% copper, has a melting point of 217 to 220 °C and is predominantly used in Japan. It is the JEITA recommended alloy for wave and [[reflow soldering]], with alternatives SnCu for wave and SnAg and SnZnBi for reflow soldering.
-** SnAg<sub>3.5</sub>Cu<sub>0.7</sub> is another commonly used alloy, with melting point of 217-218 °C.
-** SnAg<sub>3.5</sub>Cu<sub>0.9</sub>, with melting point of 217 °C, is determined by [[NIST]] to be truly [[eutectic]].
-** SnAg<sub>3.8</sub>Cu<sub>0.7</sub>, with melting point 217-218 °C, is preferred by the European IDEALS consortium for reflow soldering.
-** SnAg<sub>3.8</sub>Cu<sub>0.7</sub>Sb<sub>0.25</sub> is preferred by the European IDEALS consortium for wave soldering.
-** SnAg<sub>3.9</sub>Cu<sub>0.6</sub>, with melting point 217-223 °C, is recommended by the US [[NEMI consortium]] for reflow soldering.
-* SnCu<sub>0.7</sub>, with melting point of 227 °C, is a cheap alternative for wave soldering, recommended by the US [[NEMI consortium]].
-* SnZn<sub>9</sub>, with melting point of 199 °C, is a cheaper alloy but is prone to [[corrosion]] and oxidation.
-* SnZn<sub>8</sub>Bi<sub>3</sub>, with melting point of 191-198 °C, is also prone to [[corrosion]] and oxidation due to its zinc content.
-* SnSb<sub>5</sub>, tin with 5% of [[antimony]], is the US [[plumbing]] industry standard. Its melting point is 232-240 °C. It displays good resistance to [[thermal fatigue]] and good [[shear strength]].
-* SnAg<sub>2.5</sub>Cu<sub>0.8</sub>Sb<sub>0.5</sub> melts at 217-225 °C and is patented by [[AIM alliance]].
-* SnIn<sub>8.0</sub>Ag<sub>3.5</sub>Bi<sub>0.5</sub> melts at 197 to 208 °C and is patented by [[Matsushita]]/[[Panasonic]].
-* SnBi<sub>57</sub>Ag<sub>1</sub> melts at 137-139 °C and is patented by [[Motorola]].
-* SnBi<sub>58</sub> melts at 138 °C.
-* SnIn<sub>52</sub> melts at 118 °C and is suitable for the cases where low-temperature soldering is needed.
-Different elements serve different roles in the solder alloy:
-* [[Silver]] provides mechanical strength, but has worse [[ductility]] than lead. In absence of lead, it improves resistance to fatigue from thermal cycles.
-* [[Copper]] lowers the melting point, improves resistance to thermal cycle fatigue, and improves [[wetting]] properties of the molten solder. It also slows down the rate of dissolution of copper from the board and part leads in the liquid solder.
-* [[Bismuth]] significantly lowers the melting point and improves wettability. In presence of sufficient lead and tin, bismuth forms crystals of Sn<sub>16</sub>Pb<sub>32</sub>Bi<sub>52</sub> with melting point of only 95 °C, which diffuses along the grain boundaries and may cause a joint failure at relatively low temperatures.  A high-power part pre-tinned with an alloy of lead can therefore desolder under load when soldered with a bismuth-containing solder.
-* [[Indium]] lowers the melting point and improves ductility. In presence of lead it forms a ternary compound that undergoes phase change at 114 °C.
-* [[Zinc]] lowers the melting point and is low-cost. However it is highly susceptible to corrosion and oxidation in air, therefore zinc-containing alloys are unsuitable for some purposes, e.g. wave soldering, and zinc-containing solder pastes have shorter shelf life than zinc-free.
-* [[Antimony]] is added to increase strength without affecting wettability.
-==Solder fumes==
-The fumes produced from soldering operations are potentially dangerous. The process may generate fumes which contain [[lead oxide]] (from lead based solder).{{Fact|date=July 2008}}
-==See also==
-*[[Soldering]]
-*[[Solder paste]]
-*[[Solder sucker]]
-*[[Solderability]]
-*[[Soldering gun]]
-*[[Soldering iron]]
-*[[Welding]]
-*[[Brazing]]
-==External links==
-* [http://www.solderinguide.com/ SolderingGuide.com]
-* [http://alpha.cooksonelectronics.com/products/paste/index.asp Solder Paste Selector Guide]
-* [http://www.indium.com/products/alloychart.php Physical Properties Table: Specialty Alloys and Solders]
-* [http://www.kester.com/en-us/leadfree/alloys.aspx Lead-free solder alloys]
-* [http://www.bhavanimetals.com/Solder_Wire_Rosin_Core_Solder.htm Common Solder alloys and their melting ranges]
-* [http://www.metallurgy.nist.gov/phase/solder/solder.html Phase Diagrams of different types of solder alloys]
-* [http://www.sentryair.com/solder-fumes.htm Solder Fumes Dangers by Sentry Air Systems]
-* [http://mtdata.software.googlepages.com/periodictableSolders.htm Phase diagrams for lead free solders]
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