circuit soldring iron and desolder problems

[Nipuna56]

what is the best watt value that want to have for soldring iron that we use to solder circuit?
And what is the best desoldering method?

 

[tpetar]

I use soldering station with max 40W and with temperature control for up to 450C-500C. For regular soldering I use between 180C-190C. Its immportant to have good temp control at the top (end) of the soldering iron.

Also hot air soldering/dessoldering station is needed, you can start with cheap such as Gordak.

 

[wp100]

Hi,

Depends on what you are soldering - a good quality temp controlled iron is the best, some of the cheap ones can be useless, but if you are using fixed wattage irons then I would suggest a 15 or 18W for pcb type work and 25w+ for heavier wires etc.
Also get a type of iron that has different size bits available and buy couple of different size ones and use according to the work you are doing.

De-Solder pumps are fine for larger heavy duty pcbs but for normal pcbs and smd then Desolder Braid is better , the pumps can easily pull the finer copper tracks off
Braid is available in different widths, I find 2.5mm if fine for general pcb use.

Also get yourself a Flux Dispensing pen, treat the joints to be desoldered with it so the solder melts easier.

 

[Nipuna56]

is 30w soldring iron not suitable for PCB ?
what are the issues that can happen using high wattage iron?
what are the good soldring iron brands?

 

[tpetar]

No my friend wattage dont have nothing with that, temperature is major thing, and wattage is just amount of power for job. My thinking is that around 40W is just ok for most jobs. Also shape of top/end of soldering iron have very important rule in soldering process by transfering heat on proper way.

If you want to solder some bigger surface area (copper) and you have 10W solder iron, you can set what you want temperature but you cant get it, there is no power in iron for that job. If you want to heat up house and you set temp on 50C and you have small and weak heating oven, you cant get it, in other case if oven is proper size and power you will get wanted temp.

I didnt even mention soldering with flux and small power of soldering iron...

:wink:

 

[Nipuna56]

i decided to use goot KS or KX 30w i work iron for my work
i hope work with pic ,transistors , ics etc.
is that good for my work
if any one has a experience with goot KX ,KS please tell me what is the different between these 2 models?
what is the use of Soldering Paste?

 

[tpetar]

Soldering station must have good temperature regulation, digital will be nice. :smile:

Soldering flux is used often and its major thing. Soldering paste is used to degrease some very dirty area before soldering, I used on bigger copper area before soldering, but better use flux.

 

[Nipuna56]

Thanks friend

 

[Nipuna56]

is flux use to clean soldring area?

 

[tpetar]

To overcome oxide film, it becomes necessary in electronic soldering to use materials called fluxes. Fluxes consist of natural or synthetic rosins and sometimes chemical additives called activators.

It is the function of the flux to remove oxides and keep them removed during the soldering operation. This is accomplished by the flux action which is very corrosive at solder melt temperatures and accounts for flux's ability to rapidly remove metal oxides. In its unheated state, however, rosin flux is non-corrosive and non-conductive and thus will not affect the circuitry. It is the fluxing action of removing oxides and carrying them away, as well as preventing the reformation of new oxides that allows the solder to form the desired intermetallic bond.

Flux must melt at a temperature lower than solder so that it can do its job prior to the soldering action. It will volatilize very rapidly, thus it is mandatory that flux be melted to flow onto the work surface and not be simply volatilized by the hot iron tip to provide the full benefit of the fluxing action. There are varieties of fluxes available for many purposes and applications. The most common types include: Rosin - No Clean, Rosin - Mildly Activated and Water Soluble.

When used, liquid flux should be applied in a thin, even coat to those surfaces being joined and prior to the application of heat. Cored wire solder and solder paste should be placed in such a position that the flux can flow and cover the joints as the solder melts. Flux should be applied so that no damage will occur to the surrounding parts and materials.

Flux is also used during desoldering process to spread heat on bigger area. You can watch video examples on youtube portal.

**broken link removed**

https://en.wikipedia.org/wiki/Flux_(metallurgy)

 

[Nipuna56]

what is surface mounting soldering ?
Can " BGA SMD Soldering Paste Flux Grease RMA-223 10cc " use for soldering?
i work with lcd display ,pic , connectors, stepper and dc motors (12v),IR sensors LDR
is above product suit for my work?

 

[RetroTechie]

what is surface mounting soldering ?

Wikipedia / Google broken again? ;-)
Through-hole - "the old way", drill holes, stick wires through, solder onto bottom side (usually) of the board.
Surface mount - the new way, don't drill holes, just solder parts directly onto the board. Easier / faster / cheaper, works especially well with small and lightweight parts.
Both methods can be mixed & matched as needed (and depending on what parts are used).

Optimal is a temperature controlled soldering station of say, 30W at least. But if you go for a simple / cheap fixed-wattage iron, then for

i work with lcd display ,pic , connectors, stepper and dc motors (12v),IR sensors LDR

a 15 or 20W iron will do nicely. 30W is already on the high side for this work. For a fixed-wattage iron, higher wattage translates into higher temperature, and (as they also often come with a thicker tip) a higher heat flow from tip to work area. Very sometimes that's what you need, but most times that just serves to kill components & damage circuit boards quicker (and makes the tip corrode faster, too).

I do virtually all my soldering (SMD and through hole) with a simple but good quality 15W / 230V iron (Weller). The only situation were I run into trouble is metal layers that are both wide and thick. Like thick ground planes, the shielding around a HF circuit, etc. Which is rarely a problem since I rarely need to solder there. :grin: Sometimes I get out a cigarette lighter to pre-heat such an area a little, and presto, also done with my 15W iron.

The point is to get a few different tips for different jobs: a fine tip for fine-pitch SMD IC's, a thicker tip for soldering onto ground planes, thick wires etc.

Additional flux like from a pen or liquid dispenser is only needed in special cases: very corroded board surface / component leads, soldering flat pack IC's using the drag soldering method, etc. The common rosin core solder wire is enough for regular work (I use 0.7mm solder wire, could use 0.4 or 0.5mm since I find myself soldering small SMD parts more often lately).