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Yesterday I soldered quite some things, but I'm still a beginner.

I noticed that sometimes it happened that sometimes I use to much solder. When trying to remove it, I heat the pin with solder so it melts, and when pulling back to clean the tip to remove the excessive solder, I notice that the remaining solder on the pin just after I remove the solder tip 'grows' and leaves some kind of circle/ball-form, as if there is some air inside it. I don't think this is very good (also the result looks like a ball.

I think this is because the flux is gone after the first try.

I tried solder wick but don't get very good results with it. Would adding flux with a flux pin help? (I ordered it, but haven't received it yet).

Of course the 'real' solution is to not use too much solder (I use already 0.5). But maybe there are better tips how to 'fix' pins with too much solder.

My soldering iron: Soldering iron

My solder: solder; size: 0.5 mm

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    \$\begingroup\$ Practise , practise & practise ... \$\endgroup\$
    – Solar Mike
    Commented Sep 25, 2017 at 9:14
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    \$\begingroup\$ Flux should help. Some solder wicks work better than others. We use the Solder Wick from Chemtronics (the original?) and that works quite well. Note that there are different sizes and they behave a bit different. \$\endgroup\$
    – Arsenal
    Commented Sep 25, 2017 at 9:14
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    \$\begingroup\$ Indeed practise! I suggest to practice what you want to do on an discarded PCB, that way you get an idea of what works and what does not. Soldering skills are mostly experience based in my experience ;-) \$\endgroup\$
    – Bimpelrekkie
    Commented Sep 25, 2017 at 9:18
  • \$\begingroup\$ @Bimpelrekkie compared to the first STM32 I soldered I think I did a little bit better... but some pins look quite bad. \$\endgroup\$
    – Michel Keijzers
    Commented Sep 25, 2017 at 9:22
  • \$\begingroup\$ Scrape the wires clean of tarnish. \$\endgroup\$
    – analogsystemsrf
    Commented Sep 26, 2017 at 6:39

3 Answers 3

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As others have said, practice makes perfect. There are lots of videos on the web but unfortunately they don't all offer great advice. This series is great, John Gammell is a master. It would help if you told us what kind of iron/station you have and which lead alloy you are using.

You can do a lot of research (here's a good summary). Keep in mind that soldering is as much an art form as it is a science. People will argue up and down on which solder and flux to use like their lives depended on it. Ultimately, everyone develops their skills and finds their own preferences.

However, you can't go wrong with a Sn63/Pb37 solder with No Clean (NC) flux at a diameter of 0.020". Look for Kester, AIM or MG Chemicals for their solder line up. Order whatever is most convenient. Just stick with name brands and don't use cheap stuff ordered from the bargain bin in China.

Here are some things to consider:

  • Make sure your iron is powerful enough for the type of soldering you do. Large point-to-point soldering has different requirements for SMD or small TH. Ideally you have a temperature controlled station.
  • Make sure you have an appropriately sized and shaped tip for the work you are doing.
  • Make sure your tip is properly cleaned and not oxidized. Smother it in solder and then clean it in an wire-mesh waterless cleaner like this one
  • Make sure you apply flux generously. Flux is your friend :>).
  • If you have a station, set the temperature to ~360C. If you are dealing with large ground planes, you will either need a larger tip or a slightly higher temperature. Consider preheating the board first.
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  • \$\begingroup\$ Thanks for your detailed answer ... I checked some videos but not the one you suggested (I will do). To be honest, I'm using cheap China stuff, mostly because for me it's just a hobby project, and if something is not good, I try again (if I would have to buy all components genuinely it would cost me like $1000 probably). Especially since I lack electronic knowledge so I try a lot (and learn, which is most important for me). I use now 0.05 ... I thought that was already thin, and I think I use like 0,5 cm (0,2") per 'pin' ... but it's hard to guess. \$\endgroup\$
    – Michel Keijzers
    Commented Sep 25, 2017 at 13:35
  • \$\begingroup\$ My soldering iron is also cheap (60W, temperature controlled but without any station, thus directly connected to mains). I put it normally on 350 degrees (for pin headers). I had some bigger (non round tips) but yesterday I used a round tip and seems to work well (for me). For cleaning I had a yellow 'cloth' specifically for soldering, but now I have a 'bowl' with brass parts which is much easier to clean. To be honest, I thought adding flux was not needed ... it's already inside the solder right? Or should I use anyway flux? (I ordered a flux pen, but hasn't arrived yet). \$\endgroup\$
    – Michel Keijzers
    Commented Sep 25, 2017 at 13:35
  • \$\begingroup\$ And I don't need big parts to be soldered, just pin headers, and later resistors/ICs etc to a (small) PCB. But that will take half year (so far I'm only breadboarding but I sometimes need components or microcontrollers which have no pin headers attached. \$\endgroup\$
    – Michel Keijzers
    Commented Sep 25, 2017 at 13:37
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    \$\begingroup\$ Don't use the wet sponge for cleaning, the brass mesh is much better for your tip. As for flux, yes the solder has flux in it, at least in theory. If you are using cheap solder, it may not. Even if you're just a hobbyist, I would get some good solder at some point. Like I said, flux is your friend. \$\endgroup\$
    – Minho
    Commented Sep 25, 2017 at 13:42
  • \$\begingroup\$ Ok thanks for the flux tip ... when I get it I will use it additionally ... I just checked for 0.02" solder but that cost like 30-40 euro, but I will check later for alternative/compromises. \$\endgroup\$
    – Michel Keijzers
    Commented Sep 25, 2017 at 13:46
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Put some solder on the wick before trying to desolder something. It'll work much better that way. Flux is also a go-to tool for desoldering.

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    \$\begingroup\$ Or put a little bit of solder on the iron tip \$\endgroup\$
    – Andrejs Gasilovs
    Commented Sep 25, 2017 at 9:27
  • \$\begingroup\$ Thanks ... I ordered a flux pen, hope to use it next time. \$\endgroup\$
    – Michel Keijzers
    Commented Sep 25, 2017 at 19:40
  • \$\begingroup\$ @GAttuso If you put solder on the tip, it'll end up on the wick, which is the idea to start with. \$\endgroup\$
    – Barleyman
    Commented Sep 26, 2017 at 9:08
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Minho's answer sums up everything so perfectly, but here are my two cents. :)

I am so aware of the "ball" that you are talking about! I have had the opportunity to solder and de-solder a number of circuits thus trying different tools and products. But like everyone so rightly said, practice is the ultimate answer.

Minho pointed out how properly shaped and clean tip is important and I completely second that. I too clean the tip with brass wire mesh cleaner with rosin flux reservoir something like this, every time I go onto the next pin.

To fix the excess solder, I use de-soldering wicks like these. I place the wick over the point I want to fix, place the solder iron on top of the wick (after cleaning the tip with the cleaner I mentioned) and remove it when I see the solder is absorbed in the wick. (I know you did mentioned that you used wick, but having a clean wick and clean soldering tip is essential).

If I have to remove a stubborn component out of the PCB, I'd have a plier holding it from one side and moving the component a bit by simultaneously placing the solder iron on it from the other side, till it dis-engages with the solder around that point. Again, be cautious as to not exceed the time the iron is heating the component. Place the iron between the component and surface.

Also, I have used clear flux solder wire which I found to be good.

I hope this helps!

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  • \$\begingroup\$ THis really helps ... I only clean like every 5 pins in the brass wire mesh, I should do it much more often than. Also, what do you mean with 'rosin flux reservoir' ? Is that the container that contains the brass mesh? Or is some fluid involved? (I just scratch the tip against the mesh several times). I have also similar (but cheap) wick ... I will try again and use a bit of solder on it like Minho said. I got better results with the wick when desoldering bigger components. \$\endgroup\$
    – Michel Keijzers
    Commented Sep 25, 2017 at 14:56
  • \$\begingroup\$ I also used the plier technique ... I salvaged an old CRT tv some time ago, some components broke because of the heat but I could salvage most components (it was more to practice than to usefuly use the salvaged items). But with my pin headers I try to be more careful, especially to the components they are attached to. \$\endgroup\$
    – Michel Keijzers
    Commented Sep 25, 2017 at 14:56
  • \$\begingroup\$ So the brass mesh is sitting on top of this paste-like flux. This flux cleans out all the black oxidized material from the tip and leaves you with a metallic shiny tip (with absolutely no residue), with which you should be ideally starting the soldering a new point. This is a newbie talking about their soldering experience, so I don't know how long we should continue with this lol. \$\endgroup\$
    – AmyM
    Commented Sep 25, 2017 at 15:03
  • \$\begingroup\$ Pin headers were the worst, I did sacrifice a lot of them, I always ended up cutting them because they would refuse to come out of my PCB. \$\endgroup\$
    – AmyM
    Commented Sep 25, 2017 at 15:05
  • \$\begingroup\$ My brash mesh container only has the brash mesh, no paste-like flux ... I must buy that too I guess. My tips are not that shiny anymore, unless I use new ones. For the desoldering I ruined two completely, maybe I should post it as a separate question. \$\endgroup\$
    – Michel Keijzers
    Commented Sep 25, 2017 at 15:41

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