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Different soldering techniques

Discussion in 'General Electronics Discussion' started by Erling, Oct 2, 2012.

  1. Erling

    Erling

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    Oct 2, 2012
    Hello there.

    My question may be freak, but I'm really interested in answer.

    In my country (I'm from Russia) electronics hobby took roots very long time ago and during Soviet period it was thoroughly supported by government. So there are some traditions (traditional techniques) which were established in last hundred years of electronics hobby in my country.

    The thing is my fellow citizen almost never bring solder directly to the wire by hand (or another detail) while tinning. We usually take some solder with the soldering iron tip (not just tin the tip, but actually load tip with necessary amount of solder) and touch with the tip detail that is to be tinned. Then we slightly move tip along the detail, helping solder to flow. The same thing with PCBs: we usually bring solder to the joint with the tip. This method has obvious advantages:
    - you don't need "helping hand" device;
    - it takes less time as you don't need to heat the detail before applying solder: detail gets warm enough during as you apply solder and move tip along the detail;
    - as you don't need to heat detail before making joint, you have less chances to overheat the detail. That may be not very important while soldering wires, but that gets important if you make point-to-point circuitry, which contains semiconductor elements, which can be overheated easily.

    So, once I decided to watch YouTube and know how you, western guys, make soldering. I was very surprised to see that technique when solder is applied directly to the joint by hand (or with helping device) is a sort of "orthodox" among electronics hobbyists and professionals.
    I've watched about 30 vids about soldering techiques. 28 of them demonstrated "direct applying" technique and only 2 of them taught viewer to bring solder with the tip.

    "Direct applying" example:
    Look at this man (watch from 6:10). Joint he made is awful! He was trying to heat up the wire for more than a minute. I think it's just fail.

    "Loading the tip" example:
    Watch from 2:10. Soldering is instant.

    So my questions are:
    1. Why "direct applying" technique is so popular?
    2. Do you ever bring solder to the joint/wire with the tip? Or you always use "direct applying" technique?

    I'll be grateful for your answers.

    P.S. I've tried "direct applying" technique in my home laboratory and I have to admit it's not bad, but I still don't think it has serious advantages.

    P.P.S. http://cxem.net/beginner/beginner85.php - that's how we usually make soldering. It's in Russian, but I think video is enough. Watch from 16:30.
     
  2. davenn

    davenn Moderator

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    Greetings Erling
    welcome to the forums :)

    Agreed ... he's got the right idea..... but he's moving the tip all over the place and the solder is starting to dry joint .... yup pretty bad outcome

    direct applying is the correct way, thats why its popular, its the way any decent technical school would teach its students, its the only way to garantee a decent joint, but even then as in that video ... when you mess around at the joint too long you can still burn off all the flux and end up with a crappy joint
    It should be completed as soon as possible .... that also stops damage to heat sensitive parts

    never bring the solder to the work on the tip!!!! by the time it gets there all the flux ( rosin) has burnt off and you will almost always end up with a dry joint
    Very Very bad!! :)


    Dave
     
    Last edited: Oct 2, 2012
  3. Erling

    Erling

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    Oct 2, 2012
    Thanks :)

    I guessed the reason is interconnected with flux and it's ability to burn out. But your argument is valid only if we're talking about soldering without using additional flux (if we depend only on flux, placed in core of solder).

    Applying some good flux onto the surface which is to be tinned (or to the PCB pad), we don't depend on core flux anymore. Additional flux won't burn too quickly and bringing solder with the tip becomes quite proper way of soldering.

    Risk of oveheating is not higher than with direct applying technique: bringing flux with tip provides good heating square, detail becomes heated instantly and you don't need to hold tip near detail for too long. Just like at the second vid.
     
  4. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Carrying the solder on the tip is fine (but not optimal) IF you are applying flux to the joints in a separate prior step.

    If the solder has flux inside it, you need it to be applied to the joint, not evaporated by the time it gets there.

    The only exception to the rule is when you have solder on a pad and the device to be soldered is already (freshly) tinned. This method relies on the reflow of solder to complete the joint. It is a method used for tacking down surface mount components (and even then, I'll touch it up again once the other legs are soldered)

    I think you'll find you also get a lot more control applying the solder directly.
     
  5. Erling

    Erling

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    Oct 2, 2012
  6. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    I think you'll find that flux cores in solder are the newer technique :)

    It reduces (but does not entirely eliminate) the need for separate flux.
     
  7. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    I'm sure that many will agree there is a lot of bad advice in that thread.

    I grew up with copper tips too.

    The problem is that copper is slightly soluble in solder. This leads to erosion of the tip. One cure was to add a small amount of copper to the solder.

    The other cure is to coat the tip in something that isn't soluble.

    Part of the process of soldering is to heat the joint with the tip. To get good thermal contact, a little solder melted on the tip will increase the area of contact and dramatically speed the process.

    As you add solder to the joint, it initially melts on the iron, then as the joint heats up it melts directly on the wires (or whatever). This is how it should be.

    If the iron sticks to the joint, ot the solder fails to melt on the joint, it's an indication you need a higher powered iron (or a hotter one)
     
  8. Erling

    Erling

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    Oct 2, 2012
    So, as I see, direct applying technique is generally based on protecting core flux from evaporating. Very well, after all it's a matter of habit. As I said, bringing solder with a tip is some kind of tradition. Indeed, in USSR was no flux-core solder. Solder was shaped in rods about 8mm dia, so we had no variants except loading tip with solder. Pure rosin was used as flux. But nowadays we have flux-cored thin solder and very different fluxes. I use flux-cored solder and modern flux, but nevertheless I consider bringing solder with a tip as a quite proper way of soldering.



    By the way, some western guys would agree with my method:

    http://cs.trains.com/mrr/f/88/p/99471/1158695.aspx#1158695 Read 2nd post :)
     
  9. Erling

    Erling

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    Oct 2, 2012
    So, as I can see, direct applying technique is generally interconnected with protecting core flux from evaporation. Very well.

    After all, soldering technique is a matter of habit. As I said, bringing solder with a tip is a some sort of tradition in my country, and I know why. Mostly in USSR was no flux-core solder. Solder was shaped in rods about 8mm dia, so we had no variants except loading tip with solder. Pure rosin was used as flux. But nowadays we have flux-cored thin solder and very different fluxes.
    I use flux-cored solder and modern separate flux, but nevertheless I consider bringing solder with a tip as a quite proper way of soldering.

    Thanks, I understand that :) I have plated tips too. But I still use copper tip. Why? Maybe I find it aesthetic :)
    I file my tip once a month and have no problems with that. Also I have about 2 metres of copper wire for replacement tips and that will be enough for all my life and for 3 generations after me.
     
  10. Erling

    Erling

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    Oct 2, 2012
    Agreed. I use that when I use your direct applying technique.
     
  11. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    I'm not entirely certain that I would get my soldering advice from a model train forum.

    Sure, if I was soldering together the chassis of a model train, or something like that, then I would defer to their advice. But for electronics advice... not so much.

    One of the things I have been formally trained for is soldering. And one of the BIG NO-NO's is carrying the solder to the joint on the tip.

    You will find that most modern tips are not designed for holding solder, and those which are, are used for special purposes.
     
  12. Erling

    Erling

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    Oct 2, 2012
    I don't think it's important. For example, many of may friends, RC-hobbyists and airsoft players, are good in electronics.

    I see. That's why I said that direct applying is "orthodox" or canonical for western school.

    As for me, I use both techniques, but bringing solder with the tip is more regular way. Using additional flux almost eliminates risk of "dry joint".

    I found it out when I was becoming acquainted with plated tips. But in 50% times properly tinned tip held solder well. Anyway, that's not a problem for me. As I said, I feel fine with a copper tip.
     
  13. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    It's not just canonical. There is a reason. If you can't see it, it's no our problem.

    There's really no point in coming here to ask questions if you're already the expert.
     
  14. Erling

    Erling

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    Oct 2, 2012
    I really didn't want to be intrusive.

    I just guessed that using direct applying technique is interconnected with evaporation of flux and wanted to become sure.

    After that, I just wanted to discuss advantages and disadvantages of different techniques.

    As we were discussing soldering techniques, you've agreed that bringing solder with the tip can be fine way if additional flux is used. After that you mentioned, that direct applying gives more control and is "newer technique". In return I said that loading tip is more rapid way of soldering, no helping device is needed and additional flux neutralizes main meaning of direct applying of solder - quick evaporation of flux. After that you didn't say why else direct applying is more reasonable.

    And that was OK, because that was the purpose of topic - to discuss advantages and disadvantages. Thank you for your opinion.
     
  15. KJ6EAD

    KJ6EAD

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    Aug 13, 2011
    I'll point out two other advantages to the modern method. First; by heating the materials to be joined before applying the bulk of the solder (a small amount is carried on the tip to form a thermal bridge), better wetting is achieved and second; the quantity of solder used to form the joint can be controlled.

    How and Why to Solder Correctly:



    Quality Standards:

    http://www.ipc.org/TOC/IPC-A-610D.pdf
     
    Last edited: Oct 2, 2012
  16. Erling

    Erling

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    Oct 2, 2012
    I'm going to disagree with you. When I bring solder to the detail with tip, solder immidiately starts to flow. Thermal bridge is provided automatically, detail gets hot very quickly and wetting is excellent. And additional flux makes wetting just perfect.

    One can load tip with necessary minimum of solder. It's just a matter of experience.
     
  17. KJ6EAD

    KJ6EAD

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    I knew you would and yet I bravely posted nevertheless. ;)
     
  18. davenn

    davenn Moderator

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    As steve said you already have your way to do it even tho its not the best

    and its pretty obvious that you are not really interested in changing to a much better way
    you are very set in your own ways ....
    so be it, thats not our problem ;)
    ... there's no point discussing something when you appear that you are unwilling to listen to good advice and many years of experience

    All We all here can do is wish you best of luck with you soldering and just hope that not too many of your joints are dry ;)

    cheers
    Dave
     
    Last edited: Oct 3, 2012
  19. BobK

    BobK

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    Yeah, like what would be the point of a dry joint?

    Bob
     
  20. davenn

    davenn Moderator

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    awww Bob,

    dont you like that nice look of crystalline solder ? ;)


    D
     
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