2.4 Soldering - Basics - Soldering bits/tips

5. Bits/tips
Bits for soldering irons and guns are their essential parts. Depending on their shape, they can be used for varying purposes. Depending on material they're made of they have varying durability.

A transformer soldering gun with a soldering tip mounted and additional three tips next to it.

Bits for transformer soldering guns are quite easy to make on your own, depending on needs. With some experience it's easy to shape them by bending, twisting and cutting a copper wire, or for soldering smaller components replacing the tip with a thinner wire. They are much less durable than the heater soldering iron bits though. The ability to make new bits having just wire cutters and some pliers and the wire/cable itself at your disposal, makes that drawback not that bad - and it lets you make any bits you want to.

People preferring using soldering guns often also make non-standard soldering bits depending on needs. For example twisting the wire and cutting it or even hammering it to form a bit resembling with its tip the truncated cylindrical, or even miniwave bits for heater soldering irons.
Similarly twisting two pieces of wire and cutting one off shorter and second only a slight bit to form a sharpened end, they form bits similar to screwdriver bits for heater soldering irons. 


In my opinion it's a lot of additional work, but some seem to really like using those as I already wrote in a post about soldering tools ;P

Heater soldering iron bits (for Xytronic LF-369D):
1. A bit with 'miniwave'; 2-4 screwdriver bits 3,2mm, 2mm and 1,2mm;
5. Conical ballpoint bit. Descriptions in text.

Heater soldering iron bits would be much harder to make at home. In general trying to make those at home is pretty much a mistake except for some emergency situations maybe. Especially that brand bits while they cost around 15-25PLN (3,5-6EUR/4,5-7,5USD) and more, they are really much more durable if used properly in amateur uses you won't need to replace them in quite a while.

You can buy them in varying shapes, with different tips. The body/shaft of the bit should fit your soldering iron well - make sure you are buying a bit fitting really well with its dimensions to your iron - some owners of cheaper soldering irons buy soldering bits fitting their irons from more expensive brands, which usually work much better (better coating alloys give them much better lifespan, much better wetting characteristics etc.). 

Bits shapes.
Conical ballpoint (number 5 on the picture) - as the name suggests it's a bit with a workpiece shaped as a cone, with slightly rounded tip. Some say that they can solder most components with such bit. It seems to me however that they aren't the most comfortable ones in use because of their round cross-section - due to this they have much smaller contact surface with soldered components and in the beginning they may be harder to use properly - they always need to have a sizable drop of solder on them to have a good thermal connection with soldered components. their thin tips however allow one to tin thin pads and lands for surface mount components.
This type bits are most often added to the soldering irons as a standard (except for the cheapest heater irons plugged directly into a mains socket which often have big, wide screwdriver shaped bits). If it isn't mentioned otherwise in a description in an internet sale - usually it will be such bit. If you're buying physically in a shop, you can check it easily of course ;)
I have such bit as indeed it was added to the soldering station as standard - it is pretty much a spare one for me in case I don't have a screwdriver shaped one because it got used up and I'm waiting for a new one.


Screwdriver bit - as in its name, the shape of its working tip resembles a screwdriver or a chisel.

They have various sizes. For soldering through-hole components, the ones with wider tip are better, thanks to that it's easier to heat up soldered components. Standard pads for through-hole components have around 3-4mm (sometimes less for smaller components), so similar width of the tip would be best. For the surface mount components on the other hand thinner tips would be much better, e.g. 1,2mm (it looks very similar to conical one, but the flattened tip helps it make better thermal connection with soldered components), which will allow you to solder of most the SMD components comfortably.
Wider, bigger bits could possibly be useful in case of soldering wider wires, or in general for parts with bigger thermal capacity. I however use a transformer soldering iron for that if my smaller soldering bits can't do it.
I have three (visible on the picture, 2-4) 1,2mm for SMD, 3,2mm for through-hole components and 2mm bit sitting in a drawer unused, ordered just in case, when I wasn't yet sure what bits I'll need. It's waiting until it'll be needed as a replacement or until I'll be soldering components with pads of such diameter.
Each of those bits for Xytronic brand soldering station did cost me 22PLN (~5,5EUR/7USD) bought at a popular online auction site.

Bit with miniwave (or microwave, but it's much harder to search in internet because of those pesky microwave ovens ;)
(bit number 1 on picture)
Its name comes from the fact that in its working principle it's quite similar to wave soldering used industrially for through-hole components where soldering is dependent on surface tension.

It's a cylindrical bit, truncated at the tip at around 45 degrees angle, with the truncation surface shaped specifically - usually slightly concave - so that on its surface, thanks to surface tension, could always easily form a drop of solder.
Thanks to this specific shape it is enough to place a components with many 'legs', like all those integrated circuits, microchips and such, and then move the soldering bit (and more precisely that solder drop on its tip) over the component's leads, and with a properly made circuit board and good soldering technique all the leads should be soldered easily without creating any shorts between them, or only with single bridges - easily removed with next swipe of the bit.

Unfortunately a complicated shape means that those bits are more expensive, but at the same time they're used more rarely - only for specific purposes (though you can solder with them components other than just those with multiple 'legs'), but they speed up work a lot, and thanks to shorter heating time they decrease risk of damaging the component being soldered.
Mine did cost 45PLN (~11EUR/14USD), so twice as much as other bits for this soldering station.

Cylindrical truncated bit - it's a cylindrical bit with its tip truncated at 45 degrees angle - similarly to the miniwave, but without that concave surface. That means that it has similar traits to the miniwave, but is much worse at that because it doesn't have such surface tension of solder like in the previous bit. I personally don't use it. Because of larger mass, so also larger heat capacity it can be useful for soldering bigger components requiring more heat for heating their volume up.
Some people owning a milling machine buy those bits instead of miniwave ones and work it to create the concave surface, to save some money - it is usually done by expense of the bit's durability (the outer surface extending bit's lifetime is destroyed in the process), however from their descriptions they have enough leftover durability for that to be economically sound.


Other bits - there are various bits with very wide tips or other strange shapes fit for soldering different integrated circuits and other specific components. I can't speak precisely about them, because I've never had to use one, but it seems to me that they are a sort of a relic of not so long ago, when hot air soldering stations were much more expensive and less available - today all that can be done faster with a miniwave bit or with the hot air. It could possibly be useful for more mass-producing kind of hand soldering (bit of heater soldering iron heats components being soldered/desoldered a bit faster than hot air).


Angular bits -for many soldering irons there are bits that have a longer shaft bent at 30 or 45 degrees angle. They have working tips with same shapes as above bits. They allow soldering in various places which are hard to access, thus they can be useful in repairing things - when you don't mount components according to size, just those that are needed. They aren't a good replacement for regular bits because being bent they are slightly less comfortable in use, however they can be a good addition. Because of them having a larger volume, thus also the thermal capacity - they may need longer time to be heated up, while at the same time they may allow one to solder thicker parts a bit easier.


Hot air stations nozzles - there are various shapes of those and some overlays fitted for specific kinds of integrated circuit packages (casings), which while using a suction tool attached to the chip allow for easy desoldering or soldering (without the suction holding tool). The standard are nozzles of varying diameters and round cross-section, chosen depending on the size of components being soldered, and on how much space there is around.
Nozzles for the hot air stations usually cost around 20-30PLN (4,9-7,3EUR/6,2-9,4USD), so it's worth to look sometimes just not at the price of hot air station you're buying, but also how many nozzles are there in that price ;)



Summing it up, for most uses in electronics, just 2-3 screwdriver shaped bits will be enough. If you add miniwave bit, and possibly some hot air nozzles to that, it should be enough most of the time for most uses.


In the next post about tools for desoldering and removing components ;)

Next Post: 2.5 Soldering - Basics - What to desolder with? [editing]
Previous Post: 2.3 Soldering - Basics - Accessories
Beginning: 1. Safety rules and hazards in electrics and electronics

2.3 Soldering - Basics - Accessories

4.The stand, sponge and metal cleaner
When you are soldering, from time to time you need to lay down the soldering iron. In order to not melt something, not set something on fire and not burn yourself, it is good to have a stand for your iron.
In soldering stations usually either there is an integral stand or one added to the set which allows you to safely set the iron aside. If you have a separate soldering iron, then it might be a good idea to buy one.
There are many shapes and kinds, but as long as holding part is made of metal and its base is made from something not conducting heat - usually plastic - it doesn't really matter what specific type of stand you choose. It is rather a quite simple construction, most soldering irons have similar shape fitting most stands well ;P
If you do have a soldering station, buying a brand stand for the station might be good, because such stand might fit well to openings in the station for attaching it, but in such cases the stand usually will be already in a set with the station. The cost of a stand is a few PLN/EUR/USD so it isn't a huge expense.

My soldering station - a stand with the iron set on it and in the base of stand there is a metal cleaner/scrubber visible.

In the stand usually there is either a cellulose sponge or a brass cleaner/scrubber. They are on the longer go indispensable while soldering. And improvised solution called a sponge from a supermarket doesn't work well, believe me ;P 
Sponges made of various plastics usually slightly melt leaving hard to clean residue on soldering iron bits while a 'professional' sponge costs just a few złotys/euros/dollars, even with a container/stand for it.

If you really want, you can try with a brass cleaner - scrubber for dish washing. It is quite similar (and a slight bit cheaper) to those sold in electronics stores.
Personally after trying it out, I recommend such metal cleaner - in my opinion it works much better than a sponge. It costs around 5-6PLN (1,4EUR/1,7USD), and with a separate stand for it around 15PLN (3,6EUR/4,6USD).


You use the metal scrubber by quickly dipping the tip in it and pulling it out a few times - lightly scratching off the impurities. You'll have a very clean, shiny bit in a moment.


The use of sponge - it has to always be really damp with water, almost floating in it. It is used by quickly dipping the bit in water and quickly pulling it out - the idea is for the rapid change of temperature to make the impurities crack and fall off, swept later by sweeping the iron on the sponge. You should do it as fast as possible, so that the iron doesn't get cooled down too much, or you'd have to wait for it to heat up again, because trying to solder with cooled down tip will end in a failure or soldering errors caused by not heating components well enough.

Uwaga: niektóre niedoświadczone osoby proponują oczyszczanie grotu przy pomocy drobnego papieru ściernego. Jest to kompletne nieporozumienie jeśli mówimy o normalnym czyszczeniu - robiąc to ściera się powierzchnię grotu, która zwykle jest zwykle zrobiona ze stali, żelaza lub innych metali czy stopów mających przedłużać żywotność grotu, jednocześnie odsłaniamy miedziane wnętrze grotu, które przez to znacznie szybciej zostanie zużyte w trakcie lutowania jako że miedź powoli rozpuszcza się w lutowiu w trakcie pracy.
Użycie papieru ściernego jest na prawdę ostatecznością - jeśli grot został przez nieodpowiednie użytkowanie zapieczony tak, że nie da się go już używać bo cyna nie chce do niego przylegać.
Warning: some unexperienced people propose the cleaning of bits with small grit sandpaper (even the quite smooth one like 600 grit). This is a complete misunderstanding if we're speaking of regular cleaning - by doing that, you abrade the surface of the bit, which usually is made of steel, iron or other metals or alloys which are there to make the tip last longer, and we expose the copper core of the bit, which will become used up much faster during soldering as copper slowly dissolves in solder during work.
Using sandpaper is really a last resort measure - when the bit has been by incorrect usage burnt so badly, that it can't be used anymore because tin won't stick to it anymore despite normal cleaning.

Possibly if you make your own bits for transformer soldering iron, you can more often treat it with sandpaper - if we're making them from copper, it'd be quite hard to expose that copper more ;P
In heater soldering irons however, especially with the prices of brand bits, cleaning them with sandpaper except for really extreme cases is simply just a waste because it shortens their lifespan greatly. 


About how to not let the bit to be dirty enough to require such drastic measures I'll write in next posts concerning soldering techniques.


And in the next post more about the soldering bits and their types ;)

Next post: 2.4 Soldering - Basics - Soldering bits/tips
Previous post: 2.2 Soldering - Basics - Tin and rosin
Beginning: 1. Safety rules and hazards in electrics and electronics

2.2 Soldering - Basics - Tin and rosin

Game of Thrones has became very popular lately and in the series there are two books (parts of one tome: Storm of Swords) titled "Steel and snow" and "Blood and gold", thus I decided to name this post "Rosin and tin" aiming with this cheap move to gain the favor of fans of this series (which I myself like a lot) ;>.
That, and the fact that rosin is the most often used flux, while tin is the main component of all the soldering alloys which are being used in electronics - so it's hard to not place them in title ;)

To the topic then.


2. Soldering alloys (solder, tin, soldering filler)

Spools of solder - alloy of tin (60%) and lead (40%) - one of most popular alloys in electronics. Both solders contain flux core. Both weigh 0,1kg. On the left a spool of 0,7mm diameter (~21 gauge) wire - very good for soldering electronics, on the right 3mm diameter (~9 gauge) wire - too thick for use in electronics.

When you already have a soldering iron, you'll need soldering filler that you'll be using to solder components with.
The most common soldering alloy in amateur electronics is tin (Sn) with lead (Pb) alloy in proportion of 63% Sn 37% Pb.

This is an eutectic alloy - in normal language meaning that in a given temperature (for this alloy it's 183 Celsius or 361 Fahrenheit degrees) the alloy changes its state from solid to liquid while melting, and more importantly freezing from liquid to solid without going through a plastic phase.

It is important, as with solders not having this trait, the plastic phase - when solder for a moment is not completely liquid anymore, but it isn't completely solid yet, being soft like clay or putty - gives much bigger possibility of soldering errors caused by moving the component in not fully solid solder.
Other commonly used solder is an alloy of 60% Sn 40% Pb with similar traits to the above.
There also are many similar alloys with 1-3% additions of silver (Ag) and bismuth (Bi).


1st July 2006. an European Union directive came to life under abbreviation RoHS (Restriction of Hazardous Substances). And similar laws in other countries outside EU so it might concern you too (blah, blah, law, law, yada yada - I know ;).

Their aim is among others reducing use (and by this escaping to environment) of such substances as lead, which is harmful and accumulates in organism (so don't eat solder, don't hold it in your mouth, wash hands, don't rub your eyes, don't eat in place where you do the soldering and keep solder away from children; I already wrote more about dangers in electronics in an earlier post). 
Because of this in industrial uses in many countries it is prohibited to use solders containing lead, however its use for amateur purposes is still allowed (at least under RoHS - check your country laws to make sure).
Means that unless you are introducing your products into market by selling them, it is ok - if you plan on selling them, read those regulations to check if exceptions from them apply to you, or you'll need to use lead-free solders.


Lead-free solders are such as those below (tin is majority of the alloy, the % values are for other elements and tin completes all the left volume up to 100%; in parentheses temperatures in Celsius/Fahrenheit degrees):
Sn Ag 3,5% (221/430)
Sn Ag 2,0% (221-226/430-439)
Sn Cu 0,7% (227/440)
Sn Ag 3,5% Bi 3,0% (206-213/403-415)
Sn Bi 7,5% Ag 2,0% (207-212/404-414)
Sn Ag 3,8% Cu 0,7% (217/423)
Sn Ag 2,6% Cu 0,8% Sb 0,5% (216-222/421-432)


As can be easily noticed, the melting temperatures are higher than 183 Celsius (361 Fahrenheit) degrees of the most common tin-lead alloy.
That results in higher risk of damage to the electronic components (which isn't a huge problem with good soldering technique, maybe besides the most sensitive parts and/or equipment that is supposed to last really long and/or in a hard environment) and faster wear of the soldering tools parts (mainly the heater) and their tips.

As you can see next to some alloys there is a range of temperatures, that means that they go through a plastic phase, which as I mentioned increases risk of soldering errors.
In addition a bane of the lead-free soldering are so called tin whiskers - a problem because of which lead was introduced to soldering alloys over half century ago in the first place. With longtime usage of electronics in some soldered joints made with lead-free solder tiny needle-like structures form, which can short the circuit and in result cause a failure or destruction of the device.

Tin whiskers spontaneously forming on lead-free solder. Source: Wikipedia

Another problem is that most of the lead-free soldered joints don't shine nicely unlike lead alloy ones. As much as aesthetic aspect is not that important, it is very important that it influences the difficulty of checking the soldered joint for errors - with leaded solder, when it doesn't shine nicely, it is almost certain that it should be corrected because it either was not heated high enough or was overheated (and all flux was burnt). Lead-free solder is always matte so there is no hint like that.


Generally speaking, besides ecologic aspect, lead-free solder sucks ;P

Of course electronics companies are making efforts to discover a lead-free solder that would have as good traits as the leaded one - none did attain that goal yet though.
Even if you really like 'green' technology, I'd recommend you to start your adventure with electronics from the leaded solder - at least until you learn to solder correctly each time.
Because as I mentioned it's much easier to notice your soldering errors with the leaded solder than with the lead-free ones.
Later you can carry on to use lead-free ones if you will want to.


Forms of solder.
Most commonly known and recognized is the solder in shape of a wire.
We are mainly interested in 0,6-1mm diameters (~18-23 gauge). I personally use mainly 0,7mm (~21 gauge). It is good for through-hole components (with too thin wire you'd need to feed too big length to achieve good joint, because you'll overheat the solder and components) as well as for SMD (too thick won't let you tin tiny pads - places for soldering electronic components to them - on a circuit board and components' leads).
There are components for which smaller diameter (so higher gauge) solder wire is better - modern integrated circuits with very thin legs, but until now I didn't have need to solder them and it certainly isn't a topic for beginners, more like a specialized use.

Solder spools are usually sold in set lengths (1,5m; 3m etc.) or by a set weight (0,1kg; 0,2kg; 0,5kg) - a spool weighing 0,1kg (as in picture) is really enough for the start, later during work you'll learn how much of it you're using and how much you actually need to buy.
You can also buy solder in a vial - the wire is coiled and packed into a cylindrical container - it's supposed to be quite comfortable in use, I haven't checked myself as it costs a bit more than regular wire spool, which seems good enough for me.

You should check if given solder contains a flux (usually rosin) core (or cores). It should be written on its label.Tin without a flux (especially those thick triangle cross-section shaped rods of solder for soldering pipes and gutters) practically is useless for electronics. Why? About fluxes in next point below. Anyway, soldering with solder without flux will be uncomfortable, tedious and you'll end up using additional flux anyway.

There are various solder pastes (also called solder creams) - they are made mainly from ground solder and flux - they're good for soldering surface mount components, similarly to BGA balls which are applied through special sieves fitted for specific integrated circuits' pads and lands on the circuit boards for them.
It is comfortable and may speed up your work, but isn't indispensable - tinning such small pads is also possible and quite comfortable with a soldering iron with 'miniwave' (or 'microwave' - don't mistake with microwaves as electromagnetic waves, it has nothing in common with them, and anyway it's easier to find them in internet under 'miniwave' name, because otherwise there is lots of pesky microwave ovens in the results ;P ). More about soldering bits in further posts. 


In general regular solder wire with rosin core and additional flux will let you do almost everything.


A spool of 0,1kg solder wire 0,7mm costs around 30-35PLN (~8EUR/10USD), but it should be enough for quite long if you don't do mass production ;)

I personally also own a spool of 0,1kg of 3mm (9 gauge) solder, but I don't use it for strictly electronic purposes - it can be useful for tinning wires and quick tinning soldering iron tips.


3. Flux

Fluxes I use: 1. Rosin - almost new, used just once, 2. Rosin dissolved in alcohol in a syringe with a needle for comfortable application to soldered/desoldered places, 3. Aspirin for use in crisis situations with very dirty components giving me a headache, 4. Brushes for quickly smearing the rosin solution over larger surfaces and for washing impurities off with alcohol.

Fluxes are substances which help in soldering by chemically cleaning (reducing - deoxidizing) connected metals thanks to general reaction which can be shown as:

metal oxide + acid ==> metal + salt (which usually doesn't harm us) + water (which evaporates)


Flux is the third and last piece, next to solder and soldering iron, indispensable in soldering. It's indispensable because on the surface of components being soldered there is always thinner or thicker layer of oxidized metals they're made from - especially easily forming on copper surfaces from which copper circuits on circuit boards and various cables and wires are made.

Fluxes usually fulfill three functions:
- they remove oxides and other impurities, like fat residue from touching, or other impurities from storing components for longer time,
- they prevent oxides from forming during soldering (cutting physically the access of air),
- they make solder liquefying easier and make solder flow better - reducing its surface tension, thanks to which solder can much more easily flow in between surfaces being connected, drew in by the capillary action into small spaces, forming much better connection between soldered components wetting them well and creating a strong connection by diffusion (I wrote about that in post 2.0 ;).

While soldering of new components onto a new circuit board with fresh tin with flux core may be easy, you'll instantly learn to prize owning a stock of good flux when you start using older components e.g. from desoldering from old, not needed boards, coated with dust, dirt, greases, oxides or damaged by acid from spilled electrolytic capacitor and so on ;)
That's why I recommend starting not from soldering, but from desoldering - that teaches quite quickly a healthy habit called 'never too much rosin'. ;)

Rosin (aka colophony).

Unarguably most well known, most popular and most easily available flux, and if you for example play a violin or dance in ballet it could have other uses too ;P

Rosin is made from resin - mainly from pine. It is made after distilling turpentine from it. Rosin is a brittle yellowish-brown substance resembling a bit an amber (it's resin after all too). It easily melts in the temperatures used in soldering. It's quite flammable, so if it gets overheated on components/board/soldering tip, it'll burn leaving brownish-black residue.One uses it by quickly dipping the iron's tip into the rosin can (it usually is sold in metal cans similar to one shoe paste may be sold in), and next moving quickly a bit of molten rosin to the place we want to coat. Speed is quite important, because we don't want to burn it.

Rosin is one of 'no-clean' type fluxes, which means that it isn't necessary to wash the excess off from the soldered components and the board, thanks to the fact that abietic acid - its active substance - after cooling down stays locked inside rosin's structure, thanks to which it doesn't corrode the components and printed circuit.
Unlike many other fluxes rosin (and other 'no-clean' fluxes) create a protective layer which prevents corrosion of unprotected metal parts.
One of uses of rosin is dissolving it in 95% alcohol and 'painting' freshly etched circuit boards with it, especially if a protective layer of special paint (so called soldermask), which is supposed to protect the copper circuits, isn't made. Thanks to this procedure not only copper circuits are protected from atmospheric and humidity influences which would cause immediate oxidization, but also it is much easier to solder on such board thanks to the traits of rosin.


Rosin is easily soluble in organic solvents e.g. acetone, alcohols (among the ethyl alcohol), petrol and many others. It doesn't dissolve in water.


Thanks to that by putting solid rosin into a jar and pouring inside alcohol (I recommend using 95% pure ethyl alcohol thanks to which one can get a solution without any additional impurities, but as it costs around 15-18PLN (~4EUR/5USD) per 200ml some would rather use colorless stained alcohol which is a bit less pure, but costs around 6-7PLN (1,5EUR/2USD) per 500ml). It's worth to make as saturated solution as possible, after some amount (I won't give exact proportions as it depends on kind of used alcohol and rosin) adding just a bit of alcohol from time to time until the rosin gets dissolved completely, and no more - thanks to this you'll have more rosin in the same volume, so we will have to apply less afterwards. In addition to that a syringe with a needle is useful for precise application (you can buy it in a pharmacy for a few cents) and a brush for coating larger surfaces.


Such application of rosin is much more comfortable than moving solid rosin with iron tip - especially for tiny components.
Warning: you shouldn't use salicylic alcohol for that - the result of leaving it on the board will be forming of salicylic acid, which can digest the circuits and components, while normal ('edible') pure ethyl alcohol evaporates completely very quickly in room temperature, leaving no residue - only residue left will be whitish-yellow rosin residue.
Yes salicylic acid, popular aspirin is a flux too, very strong one, sometimes useful in extreme cases - you put the components to be soldered on a pill and heat them with soldering iron. Don't lean over it, don't breath in, the fumes are highly caustic.

Warning! As I mentioned in the post regarding safety, while molten rosin may smell quite nice similar to resin, you should not inhale it, the products of burning it (and exactly that are the fumes rising from it), contain cyclic carbon compounds which are carcinogenic.
You should always solder in a well ventilated room, if you can, also having a fan - even a simplest fan placed by your side, so that it'll push the fumes to the side, away from you.
The solder itself doesn't evaporate in such temperatures - if you can see a smoke rising from heated solder - you're burning the flux from wire core. The tin itself (or more like the lead in the alloy) isn't harmful until you eat it, put it in your eye, or any other place where mucous membranes are. So don't hold it in your mouth.


In addition to that rosin while heated may sizzle and splash around. So wear protective goggles during work.

In case of burning the rosin on a board/components being soldered it is necessary to wash the burnt residue, because it consists of carbon compounds, which conduct electricity, so they can short the circuit and cause a failure or even destruction of the circuit board and electronic components.
Wash it off with one of solvents mentioned above (again - not salicylic alcohol!).
I use 95% pure ethyl alcohol.

Sticky hands, tabletops and other tools (yes, rosin just like normal resin is sticky, especially if applied in a thin layer, just like after dissolving in alcohol) you can clean off with same alcohol or petrol (which has the the downside of leaving a smell which not everyone may like, unlike the alcohol which will evaporate very quickly without leaving a smell).
Washing hands with alcohol/petrol too often dries out the skin, so I don't recommend it, and if it would happen it's good to use some anointing (fat based) hand cream (hey, that we work with electrics/electronics, doesn't mean we have to look like untidy, dirty rednecks - no offense to clean and tidy people living in rural areas ;).

The cost of rosin is around 7PLN (1,5EUR/2USD) for 35g per container which will last quite long. The cost of alcohol I already mentioned above, and the 200ml should last a longer while too.

Other fluxes.

There are many various fluxes, among them more aggressive ones used in harder cases and for soldering more difficult materials than our components - usually those are various acids, the more difficult soldering, the higher the temperatures and the more resistant metals - the more aggressive, caustic the fluxes.

Some tin alloys for lead-free soldering also require more aggressive fluxes.
Next reason why lead-free alloys are bad ;)

Many other fluxes require washing them off with proper solvent. Unless they are, like rosin of the 'no-clean' type, which will always be mentioned on the label as it is important for the producer - he can sell 'no-clean' fluxes for higher price.


Various flux pastes are comfortable in applying onto a board, there are various liquid and spray fluxes and such - if you'll need, you'll certainly find something comfortable for the use you plan on.


In normal electronic uses with leaded soldering they're not required. If you have a problem with using rosin and its solution - go ahead and search for more precise info in internet - usually it's quite easy to find. I don't have much experience with them, as until now rosin and alcohol were good enough for me ;)


It's worth to repeat it - there's never too much flux, usually adding flux solves a large part of problems one can have in the beginning with soldering.

That would be all concerning solders and fluxes.
In the next part I'm writing about additional items for soldering iron which aren't as indispensable, but can certainly make your life easier, speed the work up and make your tools' life longer, and then in the next post will move on to the soldering bits/tips for irons, so I invite you to the further reading, and as always in case of any questions or comments - I invite to writing comments ;)

Next part: 2.3 Soldering - Basics - Accessories
Previous part: 2.1. Soldering - Basics - Which soldering tool?
Beginning: 1. Safety rules and hazards in electrics and electronics

2.1. Soldering - Basics - Which soldering tool?

What will you need?

In the beginning a few tools. They cost me around 400PLN (around 95EUR or 120USD), majority of which is the cost of soldering station.
I'll describe different types of soldering irons, guns and stations, and in next posts I'll continue the topic with some indispensable and other useful but not always necessary items, trying to give you as much information as possible and allow you for choice of cheaper or better options.
Unfortunately - with soldering gear - especially soldering irons/stations quality very often goes together with price ;)

1. What is a soldering iron?
In a quite obvious way - the most important piece of whole puzzle, indispensable in one or other form for soldering. It heats up solder (e.g. tin alloy) so that it is possible to connect pieces being soldered with the solder, or so that it is possible to pull out a component we want to replace or save for later use (e.g. from a circuit board which is broken and which we don't want to repair).

However there are many kinds of tools used for soldering on the market, of countless brands. In addition to that even experienced people working with electronics argue which are best to be used. Some say that transformer soldering gun is great for electronics, others that on the contrary, only heater soldering iron is good.
The truth is, that if someone uses one kind very well and doesn't know how to use the other - in fact it is much better for him to stay with one he likes more - it works best for him. I will show you my own opinion, trying at the same time to shed some light on the topic, in a possibly objective way.


a) Transformer soldering gun

Transformer soldering gun TopTools brand (meaning one of those cheap, low-grade ones) 100W and 3 replacement tips (the leftmost flattened one is for cutting plastics). Despite colors, do not mistake it with Optimus Prime - this is not the same kind of transformer (as far as I know!).

The name comes from its main part - transformer - thanks to which the current from mains is changed into much higher current which by flowing through a wire heats it up. That wire (or rather its part sticking outside) is at the same time the tip (or bit) - the working piece of the soldering gun which melts the solder.

Soldering guns are popular because of their high power (60-120W is a standard), thanks to which they heat up very fast - in a matter of seconds. They cool down quite fast too, which is good e.g. while soldering inside a car or in other place where it is hard to safely put away a hot soldering tool.
Newer ones usually have a small lamp illuminating the place being soldered, and often power switches with a few power levels.
Their drawback is lack of exact temperature control of their tip - people experienced in their use can 'click' the soldering gun so that the temperature is kept in optimal range during longer soldering, that however requires a lot of experience in working with the soldering gun.

Most of people working with electronics don't recommend transformer soldering guns because of that, especially to beginners - it's too easy to overheat electronic components and destroy them, too easy to burn the circuit board, too easy to let the tip cool down too much in an inappropriate moment causing soldering errors if you don't have a lot of experience in using the soldering gun.
Because of their main piece - the transformer - the soldering guns are heavy. They are many times heavier than heater soldering irons. And even quite comfortable pistol grip doesn't help when you work for a longer time - your hand will simply start hurting.

Additionally, high current flow causes emission of strong electromagnetic field around the tip. That means that small metallic components may get attached to the tip, which sometimes may be useful, usually isn't though. Moreover, some more complicated electronic components may be susceptible to strong electromagnetic fields and may get damaged.

I personally don't recommend a transformer soldering gun for electronics.

Indeed, it is good to have one, even the cheapest one in stock, because it is useful if you want to solder thicker wires or you want to solder a radiator to circuit board (some radiators have legs allowing soldering them to boards) - then with large heat capacity of soldered components, the high power will be very useful allowing to heat them up properly. Besides that, as I already mentioned, they can be comfortable in use in places where it is hard to put away safely a hot soldering tool.

The fact that it is very easy to make additional simple tips for them is also an useful trait - you just need to take a piece of copper wire of diameter proper for that soldering gun, cut it and bend into a proper shape. That means that used up tips (about how they get used up I'll write in next parts) are easily replaced with cheap, even if less durable, equivalents. Thanks to that you can also make a bit suitable for your needs - for example bending it so that it fits to the legs of integrated circuit or other component you are desoldering - so that you can heat them all up at the same time.

It is good to have one of those in stock - for special tasks ;)

I own a transformer soldering gun bought in a construction supplies market for about 20PLN (~5EUR/6USD).
It works well for my uses (even though I bought it slightly damaged - it's good to inspect well the tools you buy in such places).


b) Heater soldering iron

Heater soldering iron. I'm cheating a bit - it's a soldering iron of my soldering station, but standalone soldering irons are different from those connected to soldering stations in that they have their power supply plugged directly into a socket, or are themselves plugged directly into 230V or 130V (depending on country) mains, while in soldering stations the iron is plugged into the station (which acts as power supply).

The most popular ones are with a straight grip (as in above photo), you could also stumble upon ones with pistol grips like in transformer soldering guns though.

Their main piece is a resistive heater which heats up when the current from the mains socket or (more often) power supply flows through it and the heat is conducted to the tip.
If we speak about the simplest heater irons, this is pretty much their whole construction - however they aren't best for electronics - they don't have adjustable tip temperature. I don't recommend buying in supermarkets or construction supplies shops etc. those cheapest versions even though their prices are tempting.
Better soldering irons have a temperature regulation. Easiest way of regulating it is a simple potentiometer which allows a skilled user to adjust the temperature - however this isn't the solution that is easiest in use because you need to have enough experience to feel how to adjust the power well to the size of piece being soldered, to achieve the required temperature.
Soldering stations are better, equipped with more precise temperature regulation - with a temperature sensor in the soldering iron - but about those in a moment.

The advantage of soldering irons is that they're very light in comparison to soldering guns, so in a longer run, much more comfortable in use.
Temperature regulation allows them to keep much more stable tip temperature, thanks to which it's easier to avoid soldering errors.

They have lower power (often 15-60W), which isn't a drawback though, because in electronic uses we don't need so high power with most components, and for ones that could need it, we can turn the temperature up or use cheap transformer soldering gun we have in stock ;)
Another advantage is lack of the strong electromagnetic field.
Additionally the fact of using power supplies in most soldering irons means that we don't hold in our hands something something connected to dangerous 230V or 130V mains, and that the iron's power cable isn't under such voltage - which is important in case of some malfunction or accidentally burning the power cable with soldering tip.
Safety first - you can buy new fuses, new soldering tools, but you probably can't get a new life.
Unless you're a cat. And have 9 of them.

Their drawback are usually more expensive soldering bits (especially for brand, more expensive and better soldering irons and stations). In addition it is much harder to make one yourself, so instead you need to tinker a lot or just buy new ones dedicated for various uses.
Other drawback is longer heat up period, however usually reaching working temperature doesn't take much over minute - two, so after turning it on you can take care of getting everything else you'll need ready, and the soldering iron will manage to reach needed temperature in that time.

There are much bigger versions, with much higher power reaching 400-500W and a large bit which gives them high thermal inertia, but they don't have use in electronics - they're used for soldering plates, pipes and such, so we won't concern ourselves with them here.


c) Soldering station. 

Soldering station that I'm using. On the left the station itself with buttons visible - for changing temperature and other additional settings as well as a display showing temperature set and if the soldering tip is currently in set temperatures range or is it being currently heated. On the right soldering iron on the stand (with metal cleaner under it).

As a matter of fact it's a power supply to which a heater soldering iron most commonly is plugged in, but often not only. Its most important parts - and the cause of stations existence is that they (besides cheap chinese ones which only have potentiometer regulation) have heat sensors in soldering irons (thermocouples etc.) and electronic circuits adjusting and stabilizing the temperature.

Thanks to that we can set temperature we want and the electronics will take care of it so that it doesn't drop too low during soldering, nor rise too much. We reduce risk of not heating well enough as well as of overheating the solder and components being soldered as long as we use proper soldering technique - about which later.

More advanced stations have alarms - visual and/or sound - informing about decreasing tip temperature below set level, which may happen while soldering components with high heat capacity (large wires, radiators). There also are stations with vacuum pumps - thanks to which their soldering irons can use special tips removing the tin during desoldering.

Decent station without additional bells and whistles, and just with a heater soldering iron (mainly Xytronic brand - chinese, but quite good one, from the middle shelf unlike other chinese brands) start at around 180-200PLN (43-47EUR/54-60USD).
Do not buy cheaper stations or you'll have to pay twice, unless you plan on soldering only a few components once per month. And if you're really, really tempted, always check what opinions does given equipment have in internet - you probably won't want to buy it anymore.
Good brands (probably best known Weller for example) start at about 1000PLN (240EUR/300USD) or somewhere around that.
Of course it's always worth to read what its users write about given model to make sure that you are really buying what you need.

Me, as I was going for more economic option, but at the same time I didn't want to buy something I'll want to change to something better in a short while, I've bought LF-369D from Xytronic - medium shelf, for about 190PLN (45EUR/56USD) if my memory serves well.

Better, more expensive and advanced soldering stations often have also either in standard or as an additional option to be connected to them many additional devices:


- Hot Air soldering gun/iron.

This is a tool allowing directing a hot air flow (a few hundred Celsius degrees, up to around 800 Fahrenheit possibly) onto components being soldered/desoldered. Often it is a part of more expensive soldering stations, it also is available as separate hot air soldering station without soldering iron.

It should not be mistaken with heat guns used for stripping paint, dry out wood, shrink plastic packagings etc. which usually use much higher temperatures - using a heat gun on electronic components by people trying to save some money on equipment usually ends tragically for those components and printed circuit board. I've seen opinions that it can be done - but you can also solder with a piece of thick nail put into flame of gas oven until it's heated enough to melt tin (actually that's how first soldering irons worked).
Unfortunately, with tools for electronics, very often price means quality.

Hot air stations make work much easier with components other than through-hole ones. Soldering and (especially) desoldering of SMD (Surface Mount Device - more about electronic components and their casings will be in an article about them) is much easier using hot air. It is indispensable in soldering some components which, depending on casing, may not have any 'legs' at all, nor other leads which can be soldered from outside, only leads underneath - those can't be soldered in home conditions otherwise than with hot air (industrially soldering furnaces are used). Similarly it may be impossible to dismount various integrated circuits, even through-hole or SMD, without damage, when they are glued to the circuit board, which sometimes makes it impossible to dismount them without hot air.

Usually such stations have an option to adjust temperature and airflow strength, which with skillful use solves problem of blowing other components away during soldering, which is a problem unskilled users sometimes stumble upon. There are also available overlay pieces allowing precise heating of given component without big influence on surroundings.

For beginner or person who doesn't plan to work in nearest future with components other than through-hole ones - it isn't a compulsory tool.
If you think of electronics seriously though, sooner or later you will need a hot air station - so don't duplicate my mistake and buy a decent station with both heater soldering iron and hot air. Usually such set is slightly cheaper than buying two soldering stations separately, and at the same time takes a bit less space on the table.


- Soldering tweezers.

Soldering tweezers. Source: Wikipedia

In essence it's a tool consisting of two small heater soldering irons connected with a hinge with a spring. In use one catches the component (usually SMD) from two sides by the both leads and solder by both of them is heated simultaneously.For some stations you can buy such tweezers fitting their power supply sockets normally used by soldering iron or hot air gun.
They are supposed to be useful in soldering and desoldering SMD components.
I've never used them myself, but it seems to me (and such opinions I mainly read in internet), that it doesn't give you anything which you can't achieve similarly easily with soldering iron or hot air. Maybe it's a bit more comfortable for desoldering SMD, but I doubt it's enough to invest in it. Unless it is in a set you want to buy anyway.


- Heater/hot plate.
This is a surface connected to soldering station (or standalone) heating up to given temperature - usually around 150 Celsius (300 Fahrenheit) degrees.
It's purpose is preheating circuit board from below, while we'll be soldering/desoldering it using hot air from above.
It helps to avoid mechanic strain connected with uneven heating, especially dangerous for large integrated circuits which can be damaged during mounting/dismounting without a heater.

Many people instead of buying dedicated heaters for electronics, which aren't very cheap (200-400PLN here, making it ~48-96EUR/60-120USD) they use e.g. electric grills (costing around a quarter of that), which also have heated plates which heat up to set temperatures - which can't be adjusted so precisely for electronic purposes though, so it might be worth either to check what temperature it may achieve and sustain, or use an equipment checked already by others (it's easy to find in internet). Or make a temperature control circuit for it - which requires a bit of effort (isn't that hard though).

It is rather an additional piece - not required for beginning electronic.


- Soldering pot.
Just as the name suggests - it is a small 'pot' with a heater heating it up to solder melting temperature. In electronics it is moderately useful. It can be a standard part or can be bought as additional piece for some soldering stations, or as a separate device.
Its main use for us is ability of tinning (more about it later) very quickly many wires or other components, even very thick ones in a short time.
The cost depending on size (and brand) is around 80PLN (19EUR/24USD) and higher. I can't recommend anything specific because I don't use it - for tinning larger pieces a transformer soldering gun is enough for me as I neither do it for the living nor I need to tin a lot of components in a short time.
It probably isn't needed for a beginning electronic - unless you know that you'll be tinning large amounts of cables. If yes, then it will definitely make your life easier.


- Servicing power supply.
Some stations also have power outlets, usually with 5V, 12V, 24V and mass/grounding or with just a few of those.
It can be useful if you drive with such equipment to customers and/or don't have separate power supply allowing to test various circuits without wasting time seeking for various external power supplies you'll need.  

I doubt it is very useful for a beginning electronic (especially that very probably as one of first more serious projects you'll be making your own servicing power supply made from some old computer power supply or something similar). So if there is that functionality - it's cool, but I wouldn't choose a station specifically because of ability to use it as power supply unless you want to use it for driving to work in terrain. Or if you don't want to play with making your own cheaper power supply from computer power supply.


- IR, laser
I add it here pretty much as a curiosity, because it is an advanced and expensive equipment most electronics dream about, used mostly in industrial and/or precise and very specific fields (military, medical, space and other ones where very important equipment depends on it).
There are heaters using infrared radiation to heat circuit boards up, having similar functionality as regular hot plates/resistance heaters, but heat in a much better controlled, precise and in general better way ;P
There are laser soldering tools which heat solder with a beam of 5-30W laser (no, you can't make it from a laser pointer or a DVD laser diode), which allows for incredibly precise soldering.


d) Gas/propane soldering iron.

Propane soldering iron. Source: Wikipedia

It is a soldering iron working on the same principle as a heater soldering iron - usually also has same straight grip shape and similar tips.
What heats up the tip however is not electricity but burning gas. Usually it is regular propane gas you can buy in cans for refilling lighters (similar to spray cans, it's an expense in range around 15PLN - 3,5EUR/4,5USD per can).

It has in essence same functionality as a heater soldering iron, its major bonus however, and it's sense of existence in fact, is ability to carry it around - it's light and doesn't need mains socket to which you'd need to plug it in, at worst reloading it each 20min-1h (depending on model) with gas from the can.
Most such soldering irons have an ability to solder with tips heated with the flame, option to take off the tip and solder as with a burner (useful e.g. for soldering plates and other large pieces), and option of putting on it special nozzles for soldering with hot air - giving very big versatility to this portable device.
It isn't a first need equipment, but it is a very interesting alternative, especially if you plan on servicing in terrain, where not always is an access to mains to use electric equipment and/or you don't like walking/driving around with a lot of gear on you.

Similarly to heater soldering irons there are larger and more powerful versions for soldering gutters and large plates - which are eliminating soldering irons from that use exactly because of their portability, because they can be fed from portable propane cylinders, which may be important in places where it is hard to access mains.

That would be all about soldering tools. If I've missed something, you have any questions or just want to say what you think about this text - please write a comment ;)


In next part about fluxes - including best known rosin, and about types of solder - mainly about best known, tin alloys. They are just as indispensable as soldering tools above, so if you're interesting in it - keep reading ;)

Next part: 2.2 Soldering - Basics - Tin and rosin
Previous part: 2.0. Soldering - Basics - What is soldering?
Beginning: 1. Safety rules and hazards in electrics and electronics

2.0. Soldering - Basics - What is soldering?

In a few words of introduction, as this article has grown beyond my most optimistic expectations, for clarity and better readability I'm dividing it into a few posts - in the end of each post there will be links to last, next and first (this) page.

Soldering is a process, method of joining permanently metal objects with help of filler metal (called solder) - other metal or metals alloy heated above its melting temperature, lower than melting temperature of metals being connected. In electric and electronics uses usually those are alloys in which major part is tin (Sn), hence they often are commonly simply referred to as 'tin'.

During soldering, besides normal so called wetting - meaning very good adhesion and filling small cracks and fissures - of surfaces being soldered, there is a process of diffusion of solder into soldered surfaces - atoms of solder flow into structure of soldered surface and atoms from soldered surface partially flow into the solder.

Thanks to that very good mechanical strength, good electric and thermal conductivity are achieved.

Joint 'glued' with solder with too low temperature used vs a correctly soldered joint.

It is important that both soldered pieces and solder connecting them reach the temperature of melting of the solder - not fulfilling this requirement causes one of most common soldering errors - cold solder joint.

Simple adhesion or 'gluing' pieces together without diffusion results in a much weaker connection - mechanical, electric and thermal, which is one of soldering errors being effect of surfaces not being heated well enough. I'll write more about soldering errors in next part about soldering techniques and frequent errors. 

This method is different from welding in that the filler metal used is the only element joining surfaces being soldered, while in welding temperature is high enough to also melt edges of welded pieces to connect them stronger (at the same time in obvious way partially damaging welded surfaces).

This article mainly refers to soldering in electronics, partially in general in electrics, only with mention of other areas.
So if you want to solder stained glass, pipes or gutters - of course I invite you to read further, maybe you'll learn something interesting, however not having any experience with soldering gutters, pipes or stained glass I can't vouch for this knowledge being useful for you in what you're interested in. I am confident that there are many pages in the internet dedicated to other uses of this technique - the topic of this blog however probably doesn't include them ;)

How to begin?
Soldering is a fundamental skill which you need to obtain to be able to deal with electronics (and electrics).
As with most skills - there are some tools you need to have to be able to perform it.
Knowledge of some rules, theory is needed to not stumble around blindly and to not make simplest and at the same time most common errors which cause a failure and in effect often discourage in the very beginning.
And at last training is needed, without which everything will be just dry and moderately interesting theory. And even knowing theory very well, without practice in the beginning you probably won't be soldering ideally until you get your hand used to doing it - you won't be accustomed to it, you won't learn your own techniques and reflexes which will perform best just for you.
Thanks to all that theory however you will know where to begin from, you'll avoid some blisters and worse damage, you'll avoid destroyed electronic elements and burnt circuit boards, you'll avoid destroyed soldering iron tips thanks to which you'll avoid a lot of nerves, so if you consider avoiding those problems a worthy enterprise - I invite you to read further, as I'll carry on to the topic now ;)

Next part: 2.1. Soldering - Basics - Which soldering tool?
Previous part (and beginning): 1. Safety rules and hazards in electrics and electronics