Wiki: Soldering articles

[meow2222]

For your review and input...

Soldering

'''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.

=Methods= Different 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]]

[meow2222]

Also for review and input...

Soldering iron

==Electric Irons== There are several types.

===Standard electric iron=== The electric iron is the favoured tool for all electrical work. Its slow to heat up but maintains a fairly steady temperature, and is instantly ready for all joints after the first.

===Thermostatic electric iron=== Thermostatic irons heat up faster, and maintain ideal temperature more accurately and consistently. They maintain and recover temperature much better with large joints.

===Boostable electric iron=== These non-thermostatic irons have a boost button that can be pressed to double output power. Manual control of the button enables soldering of larger pieces and rapid repeat soldering. These irons were the forerunners of the automatic thermostatic types.

===Low voltage iron===

24v irons can be run from a [[Lead acid battery|car battery]], [[Nicad battery|cordless tool battery]], laptop battery or even series [[Zinc carbon battery|6v lantern batteries]], as well as a mains power supply. The availability of affordable gas irons has reduced the need for this trick.

Thermostatic low voltage irons can be run from voltages somewhat above or below ratings. Half rated voltage is about the bare minimum for TCP irons, making a car battery usable. Non thermostatic types have a narrow window of voltage, and don't function ok on the wrong voltage.

Standard irons use around 25w, so a [[Nicad battery|cordless tool battery]] can deliver in the region of 1 - 2 hours use.

===Cold heat iron=== The 'cold heat' soldering iron passes several volts through the resistive tip only when in contact with copper or solder. Performance is poor, and the voltage used is enough to kill some electronics.

===Soldering gun=== These heat up in around 12 seconds, but the reheat time is repeated with every joint. The tip temperature changes widely during use, adding further skill requirement and difficulty for the beginner.

Soldering guns have short duty cycle ratings that are barely adequate for work, complicating and slowing work down further.

==Other soldering tools== The other available soldering tools are listed to explain all the options.

===Melting pot=== In industry some soldered joints are made using a melting pot. The pot holds a quantity of molten metal, requiring certain safety precautions. This is not an option recommended for home use. When used these should be screwed to a heavy bench to minimise risk of severe burns.

===Gas soldering iron=== Gas irons are a cordless option. The heat is not as well controlled as electric irons, which can sometimes lead to overheated tips or patchy performance.

===Gas blowlamp=== Gas blowlamps are used for [[plumbing]] soldering. They're unsuitable for electrical joints.

===Miniature gas blowlamp=== Miniature gas blowlamps the size of a fat writing pen are available. Low cost has made them popular. These have their uses, but aren't great performers for most soldering work. They're well suited to soldering tinplate containers together, and desoldering where indiscriminate heat is acceptable (ie not for electronics). Many of these tools are prone to flaring, which is a safety issue.

===Paraffin/petrol blowlamp=== Liquid fuel blowlamp designs date back to the 1800s, and use a pressurised tank of heated highly flammable fuel, which is boiled within the lamp. These are cheaper to run than gas, but have a poor safety record. The mains risks are explosion, spraying burning fuel, and the results of being knocked over.

===Pre-war irons=== Rarely irons are seen which are placed on a gas ring to heat them. These date from the 1930s and earlier. There's probably no job for which they could be recommended, but since they are technically soldering irons, beware on ebay.

==Choosing an iron== I've used everything from industrial soldering stations to salvaged junk, and I've yet to meet an iron that couldn't make a decent joint. So the choice is not a critical one, as long as unsuitable types are avoided.

Not ideal for general electrical work:

• high power irons above 35w

• Irons below about 20w

• flame lamps with no soldering tip

• soldering guns

The worst irons don't have replaceable tips, with the heater wire wound on the metal rod that forms the tip. Although not best practice, in reality such tips are still capable of decades of use.

The best irons are thermostatic. These are useful if you do a lot of soldering, or wish to solder larger pieces. Next best are boostable irons. Availability of assorted tip shapes can be useful if you wish to do the less types of work.

See also the next section...

===Used irons=== Used irons from boot sales etc are liable to have electrical faults. Since a soldering iron is something you wrap your hand round in use, electric shocks can become fatal, and the iron should be checked to ensure the wiring's ok, the cordgrip secure, and ideally the insulation should be tested.

Very old irons tend to have a lot of corrosion at the business end. Some people remove the tip and wire brush the corrosion off, then coat the part that will be reinserted with silicone oil. This prevents the tip jamming in the iron from further corrosion.

==Tips== Irons use 2 common types of tip: plain copper and iron plated copper. Steel tips are also occasionally seen.

===Tip types=== ====Plain copper==== Older irons and budget irons use plain copper tips. These gradually wear down in use through oxidation and dissolution. When the tip has worn out of shape its simply filed down back to the desired shape.

Plain copper tips are cheap and can be filed or ground to any desired shape. The filings contain lead compounds, and should be disposed of rather than left to litter house or garden.

====Plated==== Plated tips are common on better newer irons. These tips wear much less than copper ones, as long as the plating lasts. Don't file these tips, it removes the plating.

Eventually the plate wears through. Once this happens they're no different to plain copper tips, and can be either treated like a plain copper tip or replaced.

====Steel==== Steel tips are occasionally seen at the bottom end of the market. Like plated copper, these don't dissolve in the solder over time. However they have poorer thermal capacity than copper tips, so they lose temperature more on large joints and can't do as large joints.

===Tip cleaning=== A wipe on wet denim or wet cellulose sponge removes most muck build up. Cleaning the tip now and then makes soldering easier and more sucessful.

Cellulose sponges are easily spotted by the fact that they set hard when they dry. Small cellulose sponge pads are available from the main soldering iron manufacturers.

===Tip shapes=== Various tip shapes are available. The 2 most popular shapes are cut bar and pencil.

====Cut bar==== Cut bar tips are round section bar cut across at an angle, forming an oval flat area. These are very versatile, good for almost all tasks, and are recommended for all but SMD work (surface mount electronic components).

====Pencil==== Pencil tips, like an elongated pencil tip are now very popular. These perform rather better for tiny work such as surface mount components, about the same for general PCB soldering, and less well for most other tasks. They're a good choice where surface mount components are included in the work to be soldered. Where smds won't be soldered the cut bar is probably better overall, though opinions and preferences do vary.

====IC tips==== Big rectangular tips are occasionally seen that will contact all pins on a DIL IC at once. Unfortunately for desoldering ICs these aren't very effective.

====Oddballs==== Various other shapes are also seen. The cheapest irons just use an ordinary steel nail; even these crude tips perform adequately in practice.

Perhaps the oddest tip shape I've seen was a round ended round bar slit up the middle. It turned out to be a pin from a 15A plug.

====Selections==== Better quality irons have a selection of available tips that can be changed as wanted, but each tip must be left to cool down before removal, and the new one must heat up before work. Its more realistic to use separate irons each fitted with its own tip type.

====Flat plate==== Probably the least common are the flat plate tips. These are used for cutting and welding plastics, something not that often done with soldering irons - not deliberately anyway. When doing plastic work a separate tip should be used for this, and not used for soldering. Plastic work produces burnt muck, and soldering requires the absence of such muck.

Irons should be run at lower temperature for plastic work. If run at soldering temps they will burn nearly all plastics, and burnt plastic fumes tend to be mildly toxic. Temperaure can be reduced with a transformer or [[Droppers|dropper]].

===First use=== On first use a soldering iron bit should be tinned. This means coating it with solder as soon as the solder will melt on the tip. It the solder wont initally wet the tip, just wipe it clean and try again.

===Tips for old irons==== Some irons long out of production, such as the popular Henley Solon irons, have no supplier providing new tips to fit. Sometimes there's a modern iron that takes the same diameter tips, in which case you can buy ready made tips. If not you can buy copper bar of the desired diameter from a metal stockist. Round pin plug pins are sometimes used, they come in several sizes in different plugs.

Copper, brass and bronze are all usable as tips. Steel can also be used if necessary, but provides less thermal capacity, so will limit the size of item that can be soldered.

==Mains leads== [[flex|PVC leads]] are often seen, but are only barely suitable for soldering irons. High temps are encountered within the iron body, and the hot bit usually melts through a pvc lead sooner or later.

[[flex|Rubber]] is far more durable. The best leads are silicone, these don't eventually perish as rubber does.

==Holder== A holder is recommended for soldering irons to reduce the minor risks of damage, burns, injury and fire. A holder simply keeps the iron in one place. Ready made holders are available, or a bit of scrap is easily bent to a suitable shape. The holder should have some weight and stability to it to prevent it being dragged off the table or turned over. A few irons have a hook on them, these can be hung on something instead.

==Retrofitting a boost button== Its possible to add a boost function to non-boost irons by rectifying the mains and adding an electrolytic capacitor across the supply, connected via a push switch.

Such a boost switch is used to recover from temp drops after soldering large items. They aren't intended to raise working temperature above normal.

Don't do this unless you know how to do safe work at mains voltages. Wikis are publicly editable, so if you need to rely on advice you should confirm any safety critical work elsewhere before proceeding.

The bridge rectifier should be rated 1kV, or a 600v bridge may be used if 4 small capacitors are fitted across it. 250v bridges aren't suitable.

The boost capacitor must be connected with correct polarity, and should be rated 400v. 250v capacitors are entirely unsuitable.

A small low current mains push switch is mounted in the iron handle, and the mains lead is replaced with 4 core (the capacitor is too big to mount in the iron).

A neon (with built in resistor in one lead) is connected across the capacitor to show when boost is on.

A 3uF capacitor gives around 50% power boost with a 25w iron.

If you don't know how to build it from the information provided, don't.

==See Also==

• [[Special:Allpages|Wiki Contents]]

• [[Special:Categories|Wiki Subject Categories]]

[[Category:Electrical]] [[Category:Plumbing]] [[Category:Tools]]

[The Medway Handyman]

Worth mentioning pipe cleaning brushes for the inside of fittings. I always clean inside the fitting as well as outside the pipe.

the auto pipe cleaners

[Calvin]

> Also the auto pipe cleaners

I don't see any mention of soldering jewellery (soldering silver). It's a very different process and the term "silver solder" causes much confusion as it is also used to name other solder not used for soldering silver!

[dennis]

All the electronic boards at Marconi were lead free solder as were all the repairs. You will find that everyone has or will move to lead free solder for electronics as the tin/lead solder stops being made.

It can be a bugger to work with if you try and use an old iron as they don't get hot enough (at least the decent temperature controlled ones didn't).

Anyone still using tin/lead for electronic repairs will get a shock if they buy some new lead free solder and expect it to work the same way.

[Adrian]

HI

A couple of suggestions....

...specifically about soldering in stained-glass work

Large >> high-powered - 60 - 200 watts - usually temperature-controlled

Working with lead came is particularly tricky as the melting point of the came is close to that of the solder - so the whole lot can melt at the same time, if you're not skilled / careful.

There's also copper-foil stained-glass work (where the glass edges are wrapped in a thin, self-adhesive copper foil which is then soldered - also with a high-powered iron (typically up to 150W), usually leaded 'blowpipe' solder and a liquid corrosive flux (Bakers fluid or a proprietary brand).

...but this is all getting a bit specialist and beyond the realms of general diy soldering.

Emphasise the fact that the iron & joint must be up to soldering temperature before the wire solder is applied. If the solder doesn't melt as soon as it hits the joint then continue heating & try again.

Also copper foil ..... 'Tiffany' technique (see above)

Hope this helps Adrian

[Dave Liquorice]

Not on new goods. Lead is banned in the EU. You can still get lead/tin solder and repair of old kit is still allowed for which you really need lead/tin solder as the modern lead free and old lead/tin solders don't work well together.

15W is fine for most electronic work. You only need 25W for large terminals or big coonectors. Ideally a temperature controlled iron is best, particularly these days with lead free solder that has a higher melting point and shorter plastic stage.

What for? Ah scraping wires to clean 'em.

• Small snips or wire cutters

• Small pair of pliers

Wetted? Needs an explantion ie When the solder has flowed smoothly over the metals to be joined and is not in beads or globules on the surface.

• Damp cloth - for wiping excess solder away before it hardens and for removing flux residues. Plumbing flux is acidic and can lead to green corrsion on the exterior of the pipe over time if not removed.

Or a pipe cleaner or bit of emery paper.

Yeah I'd not use a tile a it may crack or explode due to the rapid uneven heating. A heat mat is very good and doesn't retain much heat at all, it's probably easier to position than a rigid tile as well. I wouldn't like to touch a tile that has had a blow lamp on it for 20 seconds or so.

Damp cloth is better and quicker. Also allows you to tidy up drips of solder. B-)

[Arfa Daily]

There are enough official exemptions that tin-lead solder should continue to be made indefinitely. It is a common misconception in the electronic repair trade that the RoHS legislation mandates the cessation of the use of leaded solder - it doesn't. The only requirements are that any equipment placed on the market after July 2006 must be manufactured using lead-free, and legally, any repair agent must preserve that lead-free status by using only lead-free solder and components to carry out repair work on any such equipment.

There is no requirement to repair equipment made with leaded solder, with any other material and indeed, many metalurgical experts in soldering strongly recommend that the two types of solder are not mixed in the same joint, because of the possibility of it causing long-term compromise of the joint's chemical stability.

Lead-free solder is not a good replacement material for leaded solder. Since its introduction, manufacturers have had trouble with it, and as a service person, it causes me daily headaches. What was a mature and reliable technology, has been wrecked by this dreadful stuff, with bad joints being back to beyond the level they were when printed circuit construction technology was first in mass use back in the early 70's. It is mechanically poor in vibration situations, and it is accepted by the idiots who introduced the legislation, that it can't be trusted to look after your life for you. Which is why the avionics industry, medical instrument industry and the military, all have exemptions from its use. The pure tin coatings on the legs of RoHS approved components, are also causing problems with tin pest, where the coating breaks down into a powder, and compromises the joint.

Lead-free solder is also much worse at wetting metals commonly used in electronic components, which means that the fluxes used with it are slightly acidic, and much more aggressive than those used with leaded solder. They are thus more dangerous to health, and good ventilation of the work area is essential.

As far as temperature and 'feel' go, you can use an existing iron running at a typical figure of around 680 to 700 deg F, but if you try to solder any large components, you will find that the temperature drop at the tip, quickly gets you in trouble with the solder dropping below the liquidus point, and becoming 'pasty' because it is not a true eutectic alloy, as leaded solder is. This can be mitigated to some extent by using a thermostatically controlled iron, with a tight control loop which quickly responds to any drop in tip temperature. If you have a temperature controlled station, then it needs to go up to a setting of around 750 deg F. An improvement in the 'workability' of the solder is obtained by introducing a small percentage of silver into the alloy. This reduces the melting temperature by a few degrees, although still not as low as leaded solder, but increases the price per reel, by quite a substantial amount.Lead-free solder also eats the plating on your iron's tip. There are 'chemical' reasons for this, as well as the fact that you run your iron hotter which makes the plating oxidise more readily. The more aggressive flux also plays its part.

All in all, it's a very big subject, and has caused the industry no end of trouble for no real gain. 80% of the world's lead production goes to vehicle battery production, and this is almost entirely recycled. The same could have been done for recovery of lead in solder. There's no real evidence that the lead in solder was even causing any ecological problems in the first place. Some chinless wonder deep in the EU somewhere, has discovered that there is lead in solder, and that it was going into landfill, so has come up with the idea of completely changing the technology to cure this perceived problem, instead of working with the recycling industry to instead recover it. Just think of the much more tangible damage that's being done world wide, by the millions of watts of additional energy being used daily, to run the manufacturers' solder bath and reflow machines to cope with the stuff, to say nothing of the millions of hand soldering tools all over the world, which are now having to be run hotter ...

Arfa

[Dave Plowman (News)]

I don't use wire wool anymore. Nasty stuff. Screwfix and the sheds - and of course PMs - do a cleaner strip which is easier to use and long lasting. Much easier to do round the back of a pipe too.

[Dave Plowman (News)]

There are no plans to stop supplying lead solder for repair work. It is just more difficult to get.

A fixed temperature iron? Pretty rare. My solder station goes hot enough easily. Dunno of one which doesn't.

Anyone using lead free for any reason will get a shock if they expect it to work as well.

[Dave Liquorice]

I guess it depends how long you keep your fittings, I've never had a problem but then most fittings I use are still bright and shiny from manufacture...

and rotate jobbie.

[Dave Liquorice]

In the EU yes but not in the US (yet?). This has lead to some US companies pulling out of te EU market as changing to lead free techniques wasn't deemed economic.

[Frank Erskine]

And look what happened to Marconi...

[dennis]

The ones with the wrong bit. They come in different temp ratings on the ones without a thermistor in the heater. They have an alloy with different curie points to control the heater.

Obviously if you have an RF rework station or similar (a few hundred quid) you can set the temp within a degree or two and as they have variable output upto a couple of hundred watts they work well with big and small stuff.

It sure takes more skill, but it does work.

I doubt if I can do a good job with the stuff anymore as its been a few years since I did anything particularly demanding with a soldering iron. I was going to resolder some surface mount stuff on a vaio motherboard but I couldn't see the pads as they were so fine.

[dennis]

Yes I know, I was against buying Fore from the start but did they listen.... Who do you think designed the CN21 network for BT?

[DM]

Fixed temp irons are common in industrial workspaces so that the technicians cannot arse up the process too much by selecting the wrong working temp for the task.

cheers

David

[Arfa Daily]

The only irons I know of which use the Curie point principle for temperature control, are the Weller Magnastat types, which although common in the repair workplace, are by no means universal. There are many many other 'general purpose' irons in use in service workshops throughout the country, which have no means of temperature control at all, other than the designed rate at which the element can put heat into the tip, and the rate at which that heat 'leaks away' ...

It is those 'fixed temperature' types (which are of course nothing of the sort) which I guess are being referred to, and are generally unsuitable for lead-free work.

Arfa

[Owain]

50V irons are available for use in telephone exchanges.

Owain

[Dave Plowman (News)]

Not a common DIY tool I'd guess - more for a production line. I've never seen one despite having been in many a repair workshop.

Temperature controlled stations - low voltage with a 50 watt iron - can be bought for about 30 quid these days. Ideal for DIY.

[Dave Plowman (News)]

Indeed - so not much relevance to DIY.