'''Beginner's guide to soldering'''
Solders are low melting point metal alloys mainly used to join: * Electrical [[cables|wires]] & components * Copper pipes * Lead glazing
Soldering is a skill that takes practice to get right, and there are many ways to get it wrong. Following the guidance here should eliminate a lot of the potential causes of trouble, making it possible to learn relatively quickly.
=MethodsDifferent methods are used for different tasks.
Electrical soldering joins copper and tin using tin lead solder with a central core of non-corrosive flux. The joint is made with an [[Soldering irons etc|iron]].
Plumbing soldering uses solid solder (often lead free) with a separate wipe-on corrosive flux, and the joint is made with a blowlamp. Yorkshire (solder ring) fittings have the solder already in them.
Leaded glass work uses a large electric [[Soldering irons etc|iron]] to solder lead came.
Signwriting requires a high temperature iron.
==Other approaches=Anyone familiar with soldering can point out that other methods of doing things also exist, and that assorted variations from the instructions given are possible. This article is a guide aimed at beginners, who are most likely to succeed when avoiding the extra complications in the various alternative approaches.
==Electrical====Equipment==You'll need * [[Soldering irons etc|Soldering iron]], 25w or thereabouts * Solder intended for electronics use (not plumbing solder) * Sharp [[knives|knife]]
===Mechanical support==Tin/lead solder is a very weak material, and is unable to hold a joint together for long under the normal stresses that occur when a joint is moved around. A reliable joint will therefore either not be moved or will have some mechanical support.
Mechanical support is uually provided by any of: * poking the wire through a hole in the PCB * twisting the wires together * wrapping the wire round the metal its soldered to * Potting the joint (encasing it in a block of [[adhesive|resin]]) is used for some [[Taking electricity outside|outdoor electrical work]]
===Clean==First the metals to be joined must be perfectly clean. 'It'll be ok' isn't good enough. Any trace of muck can be removed with the [[knives| knife]], the result must be fully clean & shiny. Metals that aren't new and have been in use will generally need the surface abrading to remove the dull oxide surface layer.
===Clamp==When possible, hold the wire or wires to be soldered in place. When wires aren't mechanically fixed beforehand, some sort of temporary clamp will hold them while soldering.
One of the most useful clamps for this is an ordinary pair of pliers. The pliers sit on the table, and the wire is passed under the pliers and up between the 2 sides, holding it while soldering.
===Tin==If the wires aren't mechanically preattached, its best to tin each separately first before making the joint. This means coating each wire with solder. Tinning is usually not necessary, but makes the job easier.
===Join==Make the joint: apply [[Soldering irons etc|iron]] to joint, then feed some solder onto the iron tip. When the solder flows over the joint, hopefully you'll get a good joint, where the joint is wetted by the metal. When solder has flowed over all or nearly all of the joint, remove the iron. This should all take a few seconds.
When the iron is removed from a succesful joint, its necessary to keep the joint perfectly still until several seconds after the metal has solidified. Solder goes through a eutectic phase as it sets - this is a brief time when it looks solid but is in fact still semi-liquid. If movement occurs during this couple of seconds, the joint will be unreliable or fail immediately.
===Solder not wetting==A bad joint happens when solder flows on but the metal isn't wetted, so the solder doesn't flow freely over both metals being joined. When this happens, scrape any muck residue off and resolder.
The mains 2 causes of an unwetted joint are contamination of the joint and lack of active flux.
Contamination: any dirt residue or oxidation on the metal surface can cause this. You'll see a bit of blackened flux on the joint. Clean all muck off with the [[knives|knife]] & try again.
Flux exhausted: Solder used for electrical & electronic work has a central core of flux. Once heated this flux is only active for a few sconds. If making the joint takes too long, the flux will no longer be active, and a wetted joint becomes unlikely. You can't take your time over a join, its got to be done in a matter of seconds or it usually won't work.
==Plumbing====Equipment==You'll need: * blowlamp * either yorkshire fittings or end feed fittings plus solder * wire wool * a heatproof mat/ sheet/ tile in many cases
Choose your solder. Hot water and central heating circuits can use any type of plumbing solder, including leaded. Cold water, which may be used for drinking, is now required to only use lead free solder.
Use the wire wool to clean all surfaces to be soldered. They must be bright and shiny, as well as dry.
Apply a thin film of flux to the surfaces being joined.
Assemble the joint.
Position the heat protecting mat to prevent any nearby items being burnt by the blowlamp. A spare ceramic tile can be used, but these retain the heat for a while after work.
Play the flame around the joint to get roughly even heating.
Yorkshire fittings: Heat the joint until the solder becomes visible at the joint.
End feed fittings: Feed solder onto the joint all round. As long as the metal is wetted this will wick into the joint.
Let it cool off, keeping it absolutely still until the solder has set throughout the joint.
When cooled, clean any flux residue off with the wire wool. The flux residue is corrosive, and if left on will form green corrosion patches. (Copper water pipe is thick enough not to be holed by flux corrosion.)
==Glass work=Leaded glass work requires a large [[Soldering irons etc|iron]] in the region of 100w or more. Lead came is shaped & soldered rather than copper.
==Signwriting=[[Soldering irons etc|Irons]] can be used on wood for permanent signwriting. A higher temperature is used than for soft soldering. Gas irons are more suitable than electric, having a wider and higher working temperature range.
Old [[Soldering irons etc#Pre-war irons|pre-electric irons]] could also be used, but there's little motivation to use them.
==See Also=* [[Special:Allpages|Wiki Contents]] * [[Special:Categories|Wiki Subject Categories]]
[[Category:Electrical]] [[Category:Plumbing]] [[Category:Tools]]