Guide A Guide to Soldering for the newbie

A Guide to Soldering for the Newbie Modder​

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Introduction
Soldering is “the joining of metals by a fusion of alloys which have relatively low melting points". It’s used in plumbing, sculpting, metalwork, but probably the most important to the modder, electronics. This guide goes over some of the aspects of soldering, and what you should think about, and should answer some common questions.

Table of Contents:
Part 1
Introduction (duh)
The Soldering Iron
Solder
Part 2
Sleeving
How to solder a simple joint
Other considerations
Conclusion


The Soldering Iron.
This is the part that you hold The iron is the tool that you use to melt the solder to make the joint. There are two main types of iron.

The Electric Iron
These are probably the most common type of iron. They plug into a power supply, sometimes have interchangeable tips, and are rated by Watts. The heat they give off and the time it takes to heat up depends on the wattage of the iron. Some irons are “temperature controlled”, which means they have a thermostat that keeps them at a certain temperature, in order to prevent any damage to sensitive components.

The power of these irons range from about 10W to over 100W. Generally, the higher the wattage, the more the iron will cost. As a rough guide, 10W irons are generally good for working with sensitive components, but will not melt the solder very quickly, which means you have to hold the iron on for a long time, which is usually very inconvenient. A good iron would be anything from 30W upwards, and a budget iron can be bought at Maplin’s for just a fiver ( http://www.maplin.co.uk/Module.aspx?ModuleNo=32909&TabID=1&source=15&WorldID=&doy=31m1 ).

A Budget 30W Iron
Electric irons work by passing a current through a resistant heating coil in the main body of the iron, which heats up, thus heating the tip. They are very simple to power up, as all you have to do is plug in and turn on.

Electric irons can be mains powered (230/120V~ AC) or another supply (such as 12V DC for car battery supplies)

Gas Irons
Less common and more expensive, these irons can get very very hot, and usually have a selection of attachments, including soldering tips, blowtorch nozzles and heat-gun nozzles.



Gas Soldering iron tips

In their specifications, they usually have Max tip temperature, max operating time and gas capacity. They will also have a “mains iron equivalent wattage”, which gives you an idea of what their electric equivalent would be. They usually run on butane, which can be purchased from tool shops or tobacconists (its sold as lighter refill gas (must be in a pressurized container, NOT liquid!).

A Butane refill
A gas soldering iron works somewhat similar to a Bunsen burner in the first stage. When first setting up the iron, the valve is open, which gives the iron 100% oxygen intake. Inside the iron, gas burns with a blue cone flame, which is aimed towards a small element in the tip of the iron. This blue cone heats up the element, until it glows, and heats the tip. Once the element has been brought up to temperature, the value should be closed, which extinguishes the flame. Now the gas is blown directly onto the catalytic element in the tip, which will be seen to glow brightly. The element catalyses the reaction between the butane gas, being blown onto it, and the air, and so the gas is “burnt”, with no flame, which is an exothermic reaction which keeps the tip at the desired temperature.

These irons are best used when you are not near a mains outlet, and need to solder something quickly (e.g. a running repair “in the field”). Generally they’re not good value for money for a home hobbyist user, as they get through a lot of gas (which is expensive) require prepping before use and can easily damage components if set up incorrectly.

NOTE !!!, this is NOT a gas “Soldering Gun”…. Though it may have an attachment for this. A soldering gun is basically a gas torch which burns with a large flame to melt the solder. This is best used for plumbing, making joints between pipes. This is not good for electronics, as the heat cannot be applied accurately enough to the connection, and would likely fry any surrounding components. Not at all useful.

On COLD SOLDERING IRONS
They run on 4AA batteries, probably got a max power rating of about 10W, if that. The nature of them being only temporarily hot means you can get inconsistant heat if you don't have a steady hand. The tips are made of a special compound which conducts heat extremly well, which is extremly expensive! IMO, not worth the bother. But, it would be suitable for quick solder joints, I suppose... There is a thread in electronics about this. Cold Heat Soldering Irons?

Desoldering
Personally, I think “Desoldering irons” are a complete waste of money. Basically, a desoldering iron consists of a soldering iron and a suction hole to suck up the melted solder. You can get exactly the same effect by using a normal soldering iron and a desoldering pump ( available from Maplin’s here http://www.maplin.co.uk/Module.aspx?ModuleNo=3937&TabID=1&source=15&WorldID=&doy=31m1 )


You can also buy “Desoldering braid” which attaches to the solder and will help free components from a solder joint. ( http://www.maplin.co.uk/Module.aspx?ModuleNo=29016&TabID=1&source=15&WorldID=&doy=31m1 ). They can be useful when desoldering a particularly large joints, but most of the time are unnecessary.


Solder

Lead-free Silver solder

Types of Solder
There are many kinds of solder available, which are widely categorised into two different types: lead and lead free.

You can get a small list of types of solder here : http://www.efunda.com/materials/solders/types.cfm

The types of Lead solder are shown in composition by the percentages of tin to lead. Common compositions are 50/50, 60/40 and 63/47, all have the same melting point (361 ºF), but the transitional range (pasty range) is different. At 63/47, the solder turns directly from solid to liquid, but at 50/50, the solder is “pasty” up until 421ºF. Generally when soldering electronic components it is best to have a fairly fluid solder, to allow the placement of small components easily.

However, the properties for lead-free solders are different. My personal preference for solder is Tin-Silver solder, which is non-toxic and lead free, gives a good connection and is very accurate. It can be bought at Maplin’s here : http://www.maplin.co.uk/Module.aspx?ModuleNo=34965&TabID=1&source=15&WorldID=&doy=31m1 . They also sell copper lead-free solder which contains copper instead of silver and is slightly cheaper,

Many solders have a fluxed core, which is very handy for fiddly electronics jobs (we’ll come to flux in a minute!), such as the above fluxed silver solder from Maplin’s.

The best way to choose your solder is to experiment with different brands and compositions, and see what you prefer working with. The thinner gauges work best for intricate electronics work, than the larger gauges which work well for...uhh... plumbing. LOL

Flux
Flux is a sticky compound paste which melts when heated, and takes away any oxides on the surface of the contacts, and allows the solder to flow over the contacts to make a better joint. It is also used when brazing (though a different kind of flux) for the same purpose: to allow the brass to flow between the two pieces of metal and adhere correctly.

There are several types of flux, but the best for electronics work is acid-free plumber’s flux. It can be purchased from hardware stores or specialist plumbing stores.

In my opinion, flux is the best way to make a strong contaminant free joint. There are other methods for getting rid of oxidants, such as sanding the contacts with fine wet+dry paper, but in my experience they aren’t as effective as using flux.

The flux should be applied to un-tinned wires/contacts prior to soldering. As the solder is applied (and the contact heated) the flux will melt and evaporate, and the solder will flow everywhere that the flux is applied. Use sparingly!! The fumes that it gives off are toxic, and so you should be working in a well ventilated room (as you should when soldering anything), ideally under a extraction-hood.

As stated earlier, some kinds of solders have flux cores, so extra flux is not required when using this.

 

Part 2

Sleeving

There are many, many types, sizes and colours of sleeving, which should be used where possible to cover up bare wires.

The one area it is vital to use sleeving is when soldering power connectors, especially when in close proximity to the opposite pole. One example of this is when soldering a Molex power connector to a LCD screen, as the two power pins are next to each other, every effort must me made to keep the two contacts completely separate, and sleeving should be put over the bare wire left over from soldering the contact to prevent any debris falling over the two wires, or the wire fraying, shorting them.

Sleeving should cover up any bare wire that is visible after soldering a joint, to prevent shorting and protect the joint from abrasion and general abuse.

Probably the most popular kind of sleeving is heat-shrink. This is a plastic sleeving which when heated shrinks over the wire it is placed on (thus the name), and changes in viscosity. This allows to tight sleeving without exerting any force on the wire to put the sleeving on, other than the heat. They are less prone to slip off, and are very easy to apply.

To shrink heat shrink, use a soldering iron underneath the sleeving to heat it. Try not to touch it, as this would cause it to burn and get plastic all over your iron (not a good thing) and probably desolder your lovely joint. Heat-shrink doesn’t require very much heat, much less than soldering, so you can also use a lighter or a match. This usually gets soot all over the sleeving and the surrounding components though, so isn’t recommended. Here a gas iron is useful, as the exhaust lets out hot gas which is ideal for gently warming shrink wrap. A hair dryer would probably work just as well too.

The amount that the heat shrink actually shrinks depends on how it is manufactured, and should be shown with the product information. Heat shrink is available at Maplin’s here : http://www.maplin.co.uk/Module.aspx?ModuleNo=301&TabID=1&source=15&WorldID=&doy=31m1

Other kinds of sleeving can be purchased, which are non-heat shrinkable, but usually need to be stretched with a special tool over the wire, then slid into place after soldering. These kinds are particularly useful for colour coding.

How to solder a simple joint
This section goes over the process of soldering a simple joint for a wire onto a contact pin on a PCB (in this case, an LCD screen). This is quite a common joint to make for modders (especially beginners). Unfortunately, I have no digital camera, so anyone who would like to add pictures they are more than welcome.

1. Prepare
This is important. You must make sure you are in a well ventilated room, and you have a surface to solder on. It’s usually quite useful to have a clamp to hold the PCB while you solder on the wire. Make sure you have all materials to hand (solder, the wires, the PCB, optionally flux if the solder doesn’t have flux in it already). Make sure there isn’t excess bare wire

2. Tinning
Make sure you have the stripped wire end, and twist the fibres to form one, and then apply some flux (if you have separated flux). Then heat the wire, and apply a little solder and spread over the bare wire. This process is called tinning. The solder will solidify, and stick the fibres together. Repeat this process with the other connection on the PCB. Now would be a good time to put the sleeving over the wire, but move it out of the way before you solder.

3. Soldering the joint
Align the two contacts, and heat the wire. Apply a little solder, then withdraw the iron and the solder and allow to cool (or blow it to cool it quicker EDIT: Actually, don't do this, as you are likley to get a "cold joint", which is where the solder has oxidised, giving you impurities making the joint much weaker! ). You should try to keep the wire and PCB stationary while the solder is still liquid.

4. Sleeving and finishing
Now, bring the sleeving back down over the joint, and if its heat-shrinkable, position and shrink it over the joint. Perfect! If there is any excess wire sticking out, clip it off. Some people may say this is the wrong thing to do, and you should do this before soldering, but its better than having a great bit of wire sticking out.

Other considerations to make
When soldering sensitive components, such as capacitors, transistors, diodes etc. you should try and keep the heat to a minimum, and use a heatsink of some sort to stop some of the heat reaching the component. A heatsink can be anything from an old croc clip to a specialised soldering heatsink. The idea is to clip the heatsink in between where the join is being made and the component itself, and the heat is conducted away from the component. The main thing to consider when using a heatsink is make sure that its got a bigger surface area than the wire you are soldering.

Additions needed here!

Splicing
When splicing two wires together, you'll get a better joint by twisting the wires together, heating them from the bottom and applying solder to the top. As with any join, flux is required, and its advisable to put some sort of sleeving over the joint or PVC insulating tape.
(thanks for that unluckyfriedkitten)

Filing the tip
In most cases, this is a BIG NO-NO. Decent irons (in fact, even crap ones.. that £4.99 linked to earlier included) have nickel plated tips, which should never ever EVER be filed.

However, if the tip is unplated (which will be indicated on the product information) then you will probably need to file it from time to time. The absence of plating means that no matter how much you file it the surface will always be the same.

When you first get the iron, you should get a small piece of solder, wrap it around the tip with a little flux and heat the iron up. The solder will melt and coat the tip with solder. This process is called "tinning", and should be done with every iron before first usage.

Cleaning the tip
Cleaning your tip couldnt be easier. Simply heat the iron up, and wipe the hot tip on a damp sponge (supplied with most soldering iron stand kits... obviously not damp!) to remove excess solder. You may wish to re-tin the tip as described above. If you see a buildup of oxides, dip the iron quickly into some flux, or dab some flux onto the tip.

(thanks cpemma)
Conclusion
I hope that this is a good reference for any newbies to soldering, and don’t hesitate to correct me if you spot a mistake, or think I’ve missed something important. And if you can take some good quality photos to illustrate parts of the guide, please please send them to me, and I’ll host them and post them in here, along with a little credit

Bibliography
http://www.inlandcraft.com/howto/soldman/smpage8.htm
http://www.epemag.wimborne.co.uk/solderfaq.htm
http://www.vishay.com/company/brands/measurements-group/guide/tt/tt609/609b.htm

Appendix
Other links
http://tools.aubuchonhardware.com/do_it_yourself_projects/how_to_solder.asp (NOTE : it says to file the tip of the iron, but DO NOT do this if the tip is specially coated, such as the budget 30W iron linked earlier on in the guide)
http://www.svconline.com/mag/avinstall_look_soldering_irons/
http://www.metcal.com/tips/1.3.2.htm
http://www.streettech.com/archives_DIY/solderingTips.html (not particularly practical, but still got some useful bits in)
http://www.epemag.wimborne.co.uk/solderpix.htm (wow, some pictures! Cool!)
http://www.passdiy.com/howto/soldering.htm
http://www.vishay.com/company/brands/measurements-group/guide/tt/tt609/609c.htm (good for re-tinning plated tips)
http://www.qsl.net/nogaqrp/soldering/N0SS-SolderNotesV8.html (some good stuff there)

Updates:
14/07/04 - spelling and Appendix added.. pic added, and splicing added (thanks unluckyfriedkitten)
18/07/04 - Added sections Filing the tip and Cleaning the Tip - thanks cpemma
01/02/05 - I return! Updated the links (maplin's changed their website) added somthing about blowing on solder joints, changed a bit of wording..

 

Bravo people have been asking for this good job

 

Thanks

In the short time I've been here I've been answering a lot of questions about soldering, so I thought I'd fill in peoples knowlege a bit

Now all I need is a few pictures to illustrate

 

nice guide
i solder stuff all day long @ work (i fit clifford and sigma alarms amongst other stuff like sat nav) and i learnt a few bits and bobs reading that,

just a quickie for anyone extending wires thats new to soldering; for wire to wire joints you'll get a better joint by twisting the wires together and heating from underneath with the iron whilst resting the solder on the top of the joint until it begins to melt, once its started to flow the solder works its way down thru the individual strands forming a solid joint, slide over heatshink and bingo solid insulated joint,

bear in mind on thin gauge cable it dont take long to heat up, whereas some of the stuff i solder into is between 4-6 mm thick so my heatshrink has to be a lot further away from the joint cuz it gets damn hot ,melting pvc insulation dont smell good at all

 

Actually thats a point. I better add a bit about splicing too.

And no, PVC does not smell good and it gets everywhere...

 

very nice guide will be usefull when i start my soldering work

 

Ooh that's something nice to know. Whenever I do that it always comes out pretty ugly and beady... but flux isn't in my vocabulary so that may be why.

Of course, put the heatshrink over one of the wires BEFORE soldering the two together....

Nice guide

 

That will be exactly why

I'll experiment with different techniques and alternatives to flux, and will report back with the results.

 

nice quick straight to the point guide, i like it! I have 2 40w soldering irons, cheapys, but i got a little prob with em, after extensive use the points melt themselves, on both, so i have to file them. And how would i clean the iron point, it keeps getting dirty and once i left the thing on and it melted some plastic things, now its stuck to the point, lol. Next time it will b safety first!!

 

For good joints the iron tip needs to be clean and lightly coated with solder. Decent soldering irons have a plated tip and should never, ever be filed, cheap unplated copper ones get pitted by solder and flux and may need the occasional file.

Wipe the hot tip before use, when it looks dirty in use, and straight after use on a piece of slightly-damp sponge, the sponge comes with most kits or a bit can be cut off some kitchen sponges (coarse hardish types that don't melt instantly, not pan scrubber types). Wet and squeeze out as much water as possible.

 

What do you guys use to shrink heatshrink? I usually use a lighter but it often damages the wire insulation on either side of the heatshrink. I've heard of people using a hair drier but I don't want to expose equipment to lots of hot air for any period of time.

 

if you use a lighter move it fast so that it doesn't have time to build a large amount of heat, but not too fast so that the flame goes out

another method is using a hair dryer

 

thanks very much duud
i always waz a noob @ soldering
hope i can get any better thnx to this guide

 

Well ... ideally you use a heat gun set on the lowest setting with a heatshrink attachment (a sorta scoop shaped thing which holds the wire while you rotate the heat around it). Obviously not everyone has this though... a lighter would work but as I said in the guide it usually leaves soot everywhere if you're not careful.

Myself I tend to use the heat-gun attachment (NOT the blowtorch attachment ) on my gas iron to shrink it. Thats how I did my headset thing (I made a headset-mic for a drummer, made out of a coat hanger bent around a bit, with a lapell mic heatshrinked to it. Worked rather well actually! )

 

If you happen to be in zero-gravity, you might find this useful
http://science.nasa.gov/headlines/y2004/16aug_solder.htm?list1096816

 

This guide really helped me out. I got a job at a place called AI (adcanced illumination) And my job is soldering all day long. right now i'm doing pcb's with around 250 components on them. We make a lot of led lights (infact thats all we make that and the controllers) A few days ago i was working on a 100 led array. Thing is when they showed us how to solder they left out a bit, this guide filled it in.
http://www.advancedillumination.com/
Since i've been workin there i've had a few idea's for some mods.

 

Tanx for the guide it was very helpful and informative

BTW neat video i would never expected that to happen

 

A lighter is fine so long as you don't let the flame touch the tubing.

 

10x i really needed to knoe all that and most of the precautions for the 1st time i didnt do lol
thanks for that grate tut and GRAIT job