Basics about soldering and de-soldering  
    In fact there is nothing magic about the task of soldering or de-soldering - it' s first of all experience and training and repeating the training  

  after a specific amount of soldered joints every person will gain a certain level of advanced skills.....

  But it is also true: with bad tools you won't be able to get really reliable
 and good soldering joints !

  You do need good tools and a good working area with good lighting..... you can't expect good results if you don't know at which temperature
  your soldering iron is operating or if you don't have correct light in the area to watch when the tin starts melting and if it's that dark that you 
  can't watch precisely the tip of the soldering iron !


  Besides explaining basics about soldering i also will talk about aiding material and
  a bit about physics......  the picture at the right side is just an example of a working
  area .... but it gives a good idea about the quality of the light that is required in the
  working area.....

  It's also a good idea to place a antistatic protective pad in the area and you also
  should have a antistatic wristband in the area - in case that you work with static
  sensitive devices.....

  I have for example covered the entire area at my workspace with natural cork pad.
  Cork has several positive qualities..... it is antistatic and it also is resistant against
  fire and heat and it's soft and there for also protects against scratches.....


  In later parts of the page you will see several recommended aids that will be added
  sooner or later to the working area.



  One of that aids will be a large magnifying glass. Simple ones are without integrated
  lighting. The enlargement factor should be at least twice but in most cases that
  large workspace magnifying glasses offer a factor of 3,0 to 3,5 enlargement.

  It should have a stabile footing ( really heavy ! ) or it should offer the chance to be
  attached with clamps to the table.  If not you need to use a hand to hold that device
  while the hand should be available for the soldering task !

  The alternate is wearing a kind of magnifying goggles.  It's a matter of taste what kind
  of solution you will prefer..... the first option draws higher cast while the second option
  is cheaper....

   The first option restricts the magnification to limited area at workspace while the

   remaining areas will be viewed in normal size ... the second option affects the entire
   view...... ( maybe difficult for reading papers aside )


   the really expensive solutions of the first option offer integrated lighting of the




The very simple soldering irons are rather cheap and offered in a wide rage beginning at
 20 Watt up to 150 Watt. Those useable for soldering at PCB's are beginning at 25 Watt up
 to maximum of 45 Watt. Stronger soldering irons are not recommended due to the fact
 that often that kind of strong irons cause more damage than satisfying results.

 The biggest disadvantage of that kind of cheap soldering irons do not offer regulation
 of temperature. The best range of temperature for soldering is between 290 degrees
 Celsius and 380 degrees Celsius. Temperatures above that limit do cause serious
 harms to the PCB's and the components !

 This kind of soldering irons often operate at temperatures betweens 450 degrees
 Celsius up to 500 degrees Celsius ! Besides that high temperatures also cause an effect
 at the tip that is called "scale" a special kind of oxydation. This causes the soldering tin
 not to flow correct and the tip losses fast it's material as burned coal.... so the tips must
 be replaced often within short periods..... after a short while you will spend that much
 money for wasted tips ( say about 10 of the tips ) and spoiled soldering tin that the total 
 amount will exceed the amount that you would have spent for a soldering iron with
 temperature regulation !


 In every case a soldering iron should always be placed at a safe deposit stand when not
 used !


 The cheaper soldering irons with regulated temperature use for regulation a simple
 knob with mark pointing to the scale at the front-plate while the better and only a bit
 more expensive stations display the temperature by a digital display. The difference
 is relevant !

 While the simple ones are only once scaled and calibrated at the factory before the
 station is distributed to the reseller or store and then by time and drift that display
 drifts off the expected value by up to 10 % - at the other side the those with digital
 display show the temperature in degrees Celsius that is really present at the tip of
 the soldering iron ! This ensures that the temperature regulation is far more accurate !



 The sponge at the deposit stand of the soldering iron is not just for fun at that place.
 It's for cleaning off the exceeding soldering tin from the tip and keeping the soldering
 tip clean. It's there for a demanded habit to keep care that the sponge is soaked with
 water before you start with a soldering session ad then the amount of water too much
 in the sponge is  wringed out !

 In general that regulated soldering irons have a power class of 50 Watt to 65 Watt.
 This does not matter because the exceeding power won't arrive at the tip..... it is 
 prevented by the regulation ---- the reason is just to ensure that the heating procedure
 is fixed to short periods.

 The better soldering iron stations offer for the soldering iron tips made with use of



 That kind of tips have a nearly endless lifetime...... They can only become damaged
 by mechanical force and not by temperature and they are far more easy to be kept



 The perfect temperature is not a fixed point..... it's a "floating compromise" of different
 factors at a current matching point from the following factors:

  Size of junction
  size of diameter of soldering tin
  specific kind of component

  - the larger the junction the higher the demanded temperature


Average temperature dependent to size of soldering area in square mm :
2  mm 2 4 mm 2 10 mm 2 30 mm 2 50 mm 2 100 mm 2
320 o C 340 o C 360 o C 380 o C 400 o C 420 o C


  - the thicker the diameter of the soldering tin wire the higher the demanded Temperature


Average temperature dependent to diameter Ø of soldering tin in mm:

diameter 0,5 mm

diameter 0,7 mm diameter 1,0 mm diameter 1,5 mm diameter 2,0 mm diameter 2,5 mm

330 o C

340 o C 360 o C 375 o C 390 o C 405 o C



- the more sensitive the component against temperature damage the less higher the
    demanded temperature
    ( in some cases it's even mandatory to use self-fixing tweezers to lead temperature
      away from component that shall be soldered.... )


Average temperature dependent to temperature sensitive device ( datasheet ):
CMOS IC or Diode Standard TTL or
plastic covered capacitors
transistors or
large ceramic resistors
TO-220 Transistors
steel nut
310 o C 340 o C 350 o C 360 o C 430 o C


Just for orientation : The temperature used in general soldering tasks should be above
 340 degrees Celsius but below 375 degrees Celsius. But in some cases it's required to
 exceed that limit below to 310 degrees or up to high limit of 430 degrees Celsius.

One of the major rules is: Keep temparature in that range that the soldering tin gets
   liquid within 2 seconds and the Joint is finished within maximum period of another

   added 5 seconds.


The station displayed here at the right side is a professional tool that also permits performance of enhanced "reflow" jobs like:

adjusting small SMD parts or

extraction of SMD parts from a PCB or

refixing a large scale SMD Chip to a PCB or

clean extraction of sockets from PCB's.


At this point ( page ) i won't treat this topic - but i will add another page related to that topic within next weeks.

But if you intend to only buy once in lifetime a excellent tool and be sure also to handle later advanced tasks

like working with SMD parts it's worth a thought to spend 40 or 50 bucks more for a station that also offers the additional "hot air gun". In this class of tools the temperature displayed and set is regulated by digital control
and measurement at the tip and thereby this tools are very precise and professional. In general this tool stations
also use ceramic soldering tips at the soldering iron.




In general such a "heat bullit" like the soldering gun displayed at the right side in this row is for regular hobbyist a complete wrong decision / investment ! This kind of soldering guns apply far to much heat in the soldering area and damage more the components  by "frying" them - than solve the soldering job !


There are only very few cases where such a tool really is a mandatory option:

- for example if you want to solder steel nuts to a PCB as mounting junctions for transistors in TO-3 case

- or if you make circuits with very high radio or satellite frequencies and want to make a copper case
  operating as "Farady cage" to protect the circuit from emitting high frequencies in surrounding areas
  or receive such signals. 


- or soldering very thick cables ( thicker than 4 square millimeters ! )


At normal PCB's there is no kind of job that should be performed by such a tool !


In general the hobbyist should have the following aids available at the place
where soldering jobs are performed:

- a desoldering vacuum pump

- a solid stand to deposit the soldering iron while doing other tasks between soldering

- some kind of flux addon like soldering grease ( will be treated later in the this page )


- at least 2 or 3 different kinds of soldering tin with different diameters:

 1 roll with 0,5 or 0,7 mm ( for very tiny soldering jobs )
 1 roll with 1,0 or 1,5 mm ( for most soldering jobs )

 1 roll with 2mm or thicker ( for very large soldering jobs )

and if performing high performance / high quality jobs:
 1 roll of soldering tin containing with silver instead of lead


remark: the size of the jobs are related to the size of soldering area and not to amount of soldering joints !

At the soldering iron there are in general two kinds of soldering tips:


the "pen" , "pencil" or "pin" typ tips similar to the kind of tip displayed at the top of the right sided picture that put the heat at a point



the "flat" kinds of tip that put the heat in a larger area like displayed at the right as lower drawing.

If the user has the option to choose among different variations of tips fitting to his soldering iron best choices will be´2 kinds of pencil-tips one with very tiny tip and one with rather more rounded tip and one flat tip with "width" of the "blade" of about 3 to 4 mm.

If this 2 or 3 kinds of tips are present then he might also try to get a kind of "spade" tip with width of 5mm to 6 mm.

Another valuable aid is the "third hand stand".

While performing a soldering job usually both hands are "occupied":
- one hand with the soldering iron applying the heat to the soldering area

- one hand with the roll of soldering tin that applies the soldering tin to the soldering area.

So it's handy to have a kind of stand that fixes the "work-piece" or the soldering "items" ( like wires )

in "working position" - and if that stand also offers a small magnifying glass to ensure a go view
( slightly enlarged ) to the "working area" - then even the better !

The problem is that most of this kind of "aids" are rather cheap and there for rather "limited"....

They don't have a firm stand.... that might be solved by adding a larger heavy metal plate at the
bottom of the stand with 2K-glue.

The "holding clips" are not that strong to hold larger or more heavy pieces ..... this might be solved by replacing that clamps with stronger versions......


or the other alternate solution is the use of a solid or heavy jaw vise and a separate magnifying glass.


Not specific related to the topic at Applefritter - but still interesting to that guys that make attempt to perform

soldering jobs on own tasks ... In general it's a handicap that soldering jobs "offside" away from the workbench
are quite difficult to handle because there is no plug socket to the powersource.......


In such cases there are 2 solutions:

A soldering iron driven by lighter gas


a soldering iron driven by battery or accumulator.

I'm no fan of the ones running on gas .... they are rather unsafe and expensive and you often have to refill them...

That's the reason i prefer those running on battery.... like the one displayed here at the right. It operates with 4
1,5 Volt AAA-typ batteries and if you use alkaline batteries they have rather good work time ( up to 45 minutes )...

but you can also run them with AAA accumulator-batteries ( NiMg ) and that's a good solution to the environment
because then the solution is rechargeable and a second set of accumulators extends working period.

This enables the experienced user to perform soldering jobs outdoors for example at the car....


Here a basic description how to solve the task of soldering:


First place the tip of the soldering iron at the component that shall be soldered and apply heat to the wire of the component ( that's a kind of "pre-heating" ) and after about half a second holding the soldering tin close to the
soldering item so that it starts melting at the wire or the tip and the flowing down to the soldering joint and flowing
also inside of the "eye" of the soldering joint.


Then after enough soldering tin has been applied to the point take away the roll of soldering tin and then after another half of a second also draw away the soldering tip !

There are several things to pay attention:
Don't put too much soldering tin in the soldering area - but enough that soldering tin also flows inside of the junction hole !
Don't waste too much time at the soldering junction.... just enough to get the soldering tin melting smooth and flowing smooth to the soldering area. Avoid to apply too much heat to the component !

It's a compromise of heat and timing... in case of doubt hotter tip and shorter time is better than less hot tip and extended time ! In later picture I will explain this by displaying bad results and the reason for such bad results.

If you are a true novice to the task of soldering it's a good habit to first gather some exercise at the desk with

some wires before performing attempt to real PCB tasks.


There is a important reason for this kind of exercise: Training at blank wires is not time critical at all - so the novice
has plenty time to collect experience without need of being ruled by time issues! And by collecting experience the user may learn step by step to add speed to his action without taking risk of damaging components or PCB !


The second advantage by this method is that the user may perform experiments by timing and temperature to collect experience and "get the feeling for correct timing" between "pre-heating the soldering area" - "melting and adding the correct amount" of soldering tin without "flooding the soldering area with too much soldering material" and collecting

"the correct feeling at what point of time to drag away the heating source ( the soldering iron )" and waiting for the soldering junction to drop temperature and get hard and reliable contact.

The next picture displays one side of a perfect junction and at your desk you should be able to view a same result at both sides of the wire junction like this picture ! And you should at least have made 10 such Junctions without mistake to be sure that your result is not a "lucky punch" but rather more a result from collected experience !

In the following picture below you see the "model" of a bicycle....
Of course it's just a "gimmick" - but at this point it expands the demand to your abilities, because it demands higher skills and  advanced recognition to your timing still without taking risk to damage real components....


You can't expand the time of applying heat that much like in earlier exercises.... otherwise you take risk of weakening other soldered junctions that you have soldered previously......


you collect experience with use of the "third hand aid" or positioning items previously ahead of the soldering task
- but avoid to add to much pressure to the items that shall be soldered and avoid dislocating the items and by that 
expanding the gap between the items.

You must learn to keep items that shall be soldered together as close as possible together and thereby minimizing the gap and reducing the required amount of soldering tin to the soldering area to minimum amount possible.


For this kind of "Gimmicks" you should use 1,0 mm thick copper wire and later also try the use of 0,5 mm thick copper wire. As "Gimmicks" you might try a model of a car or aeroplane or a boat depending to the item that gives you most fun....

 While performing this task of soldering wire models it's a good idea also to exercise "bad habits" like exceeding the time of soldering too much....
Watch how the characteristics of the soldering tin change if you remain too long period at the soldering area or how the time shortens down with change of this characteristics by higher temperature !

The reason is that inside of the soldering tin there is a tiny core with additives that permit the soldering tin
to melt smooth and run in smooth fluid condition and then the soldering tin gets "sticky" and looses it's
ability to flow smooth
.... it starts to stick at the soldering tip and starts to "glue like chewing gum" and looses it's ability to flow instantly...... get the feeling for the soldering material you use and the correct timing and avoid in later exercises to exceed your timing and avoid that your soldering tin gets "sticky" !

If you stay later too long period or have wrong temperature the soldering tin won't flow into the PCB hole
and it won't flow smooth in the soldering area. Collect experience to recognize such state "by sight" and

learn to avoid this "state" otherwise you take risk to 2 kinds of damage: you might harm the components
by exposing them too much time to the heat of the soldering iron and the "bonding" of the items will turn bad....
  and besides this effects at aged PCB's you take risk that traces may loose contact to the PCB and tear off !

You must be aware that "bonding" ( glue attachment ) between PCB and the copperlayer was not that
good like nowadays... the adhesive power between PCB and copper layer of early PCB's isn't that strong.

That's also a reason that you must learn to keep each soldering task within it's optimum of timeframe. That's also the reason to also perform some exercise soldering at damaged new PCB's from the

recycling yard before you start attempts to solder at old PCB's !  

Besides some drawings that display common mistakes made while soldering.

















But far better than drawings such mistakes may be recognized by viewing the following pictures and comparing them to the view of correct soldering jobs !



In next step you may perform step ahead from PCB with simple large PCB traces and PCB holes at single sided or double sided PCB's towards PCB's with far thinner traces and smaller soldering joints.

It's a step ahead shortening time of soldering and speeding up your task ! Every step ahead in this row of exercises forces you to speed up your tasks and keeping your soldering time long enough to get the soldering tin flowing correct in the soldering area and then "leave the place of action" as soon as possible without taking risk to produce so called "cold soldering junction". It's slowly training your abilities by collecting experience and by that also acquire the ability to judge the correct timing by instinctively "feeling the individual need" of each specific junction.


This is a view to a classic so called "cold soldering junction" where the soldering tin did not get correct connection with the trace
due to the fact that the soldering time was too short or the temperature was too low !

And this PCB display various mistakes ... among also the mistake of "frying" the PCB and thereby damaging the trace resulting to the fact that the trace went off the PCB and needed to be replaced by wire...... the change in the color of the PCB is typical indicator of such BBQ-parties ! Ad besides it's also rather sure that the related components have been damaged too by the BBQ !

A special case is the use of the so called "soldering needle"..... That a mini-
ature soldering iron for use with 12 Volt and it's size is comparable to a normal pencil !

It's "heating power" is limited to average 10 Watt to 15 Watt. But that's far enough to heat up the very tiny tip to 360 degrees Celsius to 380 degrees Celsius !

Just to get an impression: at old PCB's the traces had a width of 2 mm to 2,5 mm. In modern PCB's the traces at so called "Very High Compressed Devices" in SMD- technology are only with widths of 0,17 mm !

The next picture in the following row displays such a device and such a device can only be soldered either by a reflow device ( see such a station with "hot air gun" at upper part of the page ) or by use of such a "soldering needle" !

In such tasks it a
lso is mandatory that while performing such a task a "oversize" magnifying glass is used !

This is a soldering job really only for very experienced users !
Here we start about the topic
of de-soldering !

The user might face the need of desoldering components by different reasons....
just some examples:
- a ancients PCB contains some obsolete components that not not obtainable any more ( even not from
   resellers at recycling yards )
- the PCB contains a component that has been made as unique individual part

- the part is still intact in a damaged PCB and the part was unfortunately very very expensive.....

In such cases the user is lucky if that components are located in a socket....

but according to Murphy's law all parts that you need are soldered and that parts you don't need are placed in sockets.....


You can split this kind of tasks in two basic methods:


de-soldering by use of vacuum pump or similar tool

de-soldering by use of aids like solder wick ( see picture at right side ...)

and a third alternate attempt to extract parts not by removing the soldering tin but instead just heating it
till it becomes ´liquid and the pull out the part ( by use of a "hot air gun" ) .... but this does not only demand a advanced set of tools but also very experienced knowledge about use of heat....

( it's so delicate to use this method because it bears the risk of damaging the part..... )


solder wick is sold with different widths   ....

That solder wick is a kind of braided copper material that has been dunked in a fluid that speeds up the soldering tin to get very liquid. After that aiding stuff got dry that wick gats cut in lengths of 2 to 5 meter and winded in small supply case.

When it gets heated it supports the tin to get very liquid and sucks that soldering tin in the wick. The process of sucking the tin results from a power called "capillary pressure".  There is one trouble with that wick: You never know which period of time that wick has been stored on the shelf in the store......

and the wick looses by time it's ability to aid the tin getting liquid....


In such cases it's a good idea to apply by yourself some Kolophonium or other soldering aid like soldering grease to the wick. Few pictures below there is a picture of a common used soldering aid spray. I usually use that to add a short spray shot of it to the wick and it then immediately again recovers it's ability to support the tin getting liquid and supporting the wick to suck away the soldering tin from the cleaning area.


The explanation of the task itself is rather short and simple:

Heat the soldering wick on top of the soldering tin that is to be removed ( and use at slightly higher temperature than usually by soldering ) till the soldering tin gets fluid and gets sucked by the soldering wick. When soldering wick is full with soldering tin slowly drag the clean soldering wick below the soldering tip towards the "cleaning area" till the complete amount of the soldering tin is removed.


Note: As explained above the soldering wick is sold in different widths and the larger the amount of soldering tin is that is to be removed the larger width of soldering wick should be choosen for that task.


This is a kind of task that also is very dependent to experience - so it's a very good idea to collect some experience at a "exercising board" at the beginning to get experience of requested heat and timing and the speed that you may drag soldering wick across the cleaning area.


And bear in mind: On long term this is a rather expensive method of de-soldering. The method using the vacuum pump is cheaper and nearly same effective.... the wick method should only be used if the vacuum method is not handy due to the missing ability to get access to the opposite side of the soldering joint
( for example below a component or socket ).


The very moment you can access at the component side also the soldering joint it's the far better method

and choice to use the vacuum pump.

There are several videos available at youtube that display the methods and I place here several links to that videos to see the task in real movements:
displays use of the soldering wick

displays how to desolder with a de soldering vacuum pump


and at :

you may watch the advanced de-soldering a TQFP-IC with a hot air station
- in such cases it's sometimes recomended to "cleanup the site" from remaining soldering tin with soldering wick to end up with really clean area !

another general explanation at:


or at:


and finally at:




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