Soldering never really works

Discussion in 'General Electronics Chat' started by hjtjtjjjj, Dec 29, 2013.

  1. hjtjtjjjj

    Thread Starter New Member

    Dec 29, 2013
    3
    0
    Hey guys,

    I hope i'm posting this in the right forum, if not i'd like to apologize.

    Recently i bought a cheap soldering iron and have been trying to solder some stuff together (my current goal is to solder a pin header to a router board) however i can't seem to get it to work at all, the solder just won't melt.

    According to some tutorials i'm supposed to cover the tip of the soldering iron with tin before getting started. Even after giving the soldering iron 10-15 minutes to heat up the solder still needs about 15 seconds to melt when applied directly on the soldering iron. Once the first bit has melted it will cut through the rest like butter. It does not cover the tip though and just forms a "ball" together with the other solder. Here is a picture:

    [​IMG]


    The soldering iron i bought draws ~25 watts and i'm using Sn 99.3% Cu 0.7% lead-free solder.

    Can anyone give me advice on what i'm doing wrong?

    Thanks in advance
     
  2. bob800

    Member

    Dec 10, 2011
    48
    3
    First of all the lead-free solder has a significantly higher melting point than ordinary 60/40 Sn/Pb solder, which is probably causing the slow melting. Can you use regular solder? If not, I'd suggest getting a higher quality (preferably temperature-controlled) soldering iron which could get hotter than the one you own.

    Also the fact that the solder doesn't stick to the tip suggests that the tip isn't clean. From the picture it appears that way--when you heat the iron up for the first time, you are supposed to cover or "tin" the tip with solder to act as a protective coating.

    The solder you are using is "rosin core" electronics solder, correct?
     
  3. hjtjtjjjj

    Thread Starter New Member

    Dec 29, 2013
    3
    0
    Thanks for your reply.

    I'll try to buy 60/40 solder tomorrow.

    Is there any special way to clean it or will it work with just generic soap+water?

    It appears to be solid:

    [​IMG]

    This is the solder that came for free with the soldering iron so it's probably the cheapest crap they could find.
     
  4. Markd77

    Senior Member

    Sep 7, 2009
    2,803
    594
    If it's solid solder then that explains the problem. Without flux the solder won't flow properly or bond well to surfaces. You can use very fine wet and dry paper to clean the tip if it needs it, some tips have a metal coating over a different metal core so you don't want to wear through it.
     
  5. kubeek

    AAC Fanatic!

    Sep 20, 2005
    4,669
    804
    Just get a pack of rosin flux and try doing it again. For cleaning the tip, I usually just dip the heated iron into the rosin flux, then coat it with a bit of solder, repeat if necessary and then get rid of the excess solder using the wet sponge or brass filings type cleaner, or even a stack of newspaper will work, but might damage the tip over time.
     
  6. bob800

    Member

    Dec 10, 2011
    48
    3
    Actually if it came with the iron it probably is rosin-core solder. As far as I can tell, you can't simply look at a cross-section of the solder to determine whether or not it contains rosin--a cross section of my solder looks solid also, though it is actually "rosin core".
     
  7. crutschow

    Expert

    Mar 14, 2008
    12,981
    3,221
    Having some rosin flux is always good for soldering as well as tinning the iron, even if you have rosin core solder. It allows you to coat the tip/wire/pins with a thin coating of flux prior to soldering. That will allow the solder to readily flow and wet the surfaces and minimize the chance of overheating and damaging whatever you are soldering. Generally you then have to hold the tip only for a second or two against the joint, just until the solder flows and completely covers the joint.
     
    djsfantasi likes this.
  8. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
    2,793
    829
    While heating up the iron for the first time, it will develop oxides that make it difficult for the solder to coat it. I usually use a bit of flux at this time to reclean the tip. Also, if you apply the solder before the tip has had a chance to heat up sufficiently just shake off the solder ball, wipe the tip clean and try again a few seconds later.
     
  9. t06afre

    AAC Fanatic!

    May 11, 2009
    5,939
    1,222
    So you can not solder anything together? It could be the solder tip. The solder that you got with the iron. Should (most probably) be solder made for electronic solder work.
     
  10. sirch2

    Well-Known Member

    Jan 21, 2013
    1,008
    351
    If the solder smokes when melted it is most likely flux cored. Wiping the tip of the iron on a damp cloth or sponge and then immediately getting some flux/solder on it usually works for me.
     
  11. tubeguy

    Well-Known Member

    Nov 3, 2012
    1,157
    197
    Make sure the the tip setscrew is tight.
     
  12. trader007

    Active Member

    Feb 27, 2010
    222
    19
    wow, honestly i think OP needs to watch a youtube video, or 3. I am sure there are good guides on basic soldering out there.

    But for cliffnotes-

    1) let iron heat up, and use a wet towel to clean the tip. The steam it creates will blast off any contaminates. Your tip should always be shiny and looking like-new. If it looks dirty, then it is dirty and it won't work.

    2) use flux on your work. If you dont, it will almost never work. Dont worry if you have flux core or solid solder, even if you have flux core you still need to add your own flux prior to soldering. Flux is essential, it not only cleans but it allows heat to flow better.

    3) Tin your work before working. Tinning means to melt a little solder to your work before you try connecting the pieces. It's not ideal in EVERY situation, but it usually makes things much much easier.
     
  13. KJ6EAD

    Senior Member

    Apr 30, 2011
    1,425
    363
  14. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    5,435
    1,305
    Buy a better soldering iron! That tip type on yours is terrible and will never work that well.

    You can get a handheld 40W iron with a proper screw-on Hakko style tip AND internal electronic temperature regulation for about $25. I have one in my carry bag for field work.
     
  15. DerStrom8

    Well-Known Member

    Feb 20, 2011
    2,428
    1,328
    I suggest buying a new tip for your iron (if it's replaceable--ALWAYS buy irons with replaceable tips) and starting over again. The idea is to "tin" the tip AS it's heating up. And as others have mentioned, you'd be better off not using lead-free solder. I use 60/40 lead-tin rosin-core solder, and I highly recommend it. For most soldering jobs you want to use some very fine solder (IIRC I use 0.032 inch, but I'd recommend smaller). If you don't tin the tip of your iron when it's brand new, it'll oxidize and you'll never be able to tin it. That's why I suggested you buy a new tip. I have a very cheap ($7) 15W iron from RadioShack, and it still works great, since I tinned it at the start of the very first use.

    Hope this helps!
    Regards,
    Matt
     
  16. t06afre

    AAC Fanatic!

    May 11, 2009
    5,939
    1,222
    No it has nothing to do with this. It is the alloy that they have used to plate the raw copper in the tip. That has most to say then it comes to soldering tips and their lifetime. The cheap ones use some sort of alloy that oxidize then used. And after a short while they may become impossible to solder with (non-wettability). You can fix this by filing down(use fine grade sand paper) the plating on the tip area that comes in contact with the solder. File it down to you se bare coper. But by doing so the flux in the solder will attack the tip aggressively. And the copper will also oxidize much faster in the heat. So the tip has to be refurbished quite often. Use ONLY this trick on cheap iron tips. It must also be said that the change from a Lead bearing solder alloy to Lead Free has a negative effect on the solder tip lifetime
     
    Last edited: Dec 30, 2013
  17. DerStrom8

    Well-Known Member

    Feb 20, 2011
    2,428
    1,328
    Regardless of what iron you use, you still need to tin the tip. That's a fact. If you don't tin it the first time you use it, it will oxidize and prevent heat transfer. Sure, you can file it down again, but that causes fissures in the tip that you can't really tin, causing them to oxidize and significantly shorten the life span of the iron tip. Copper oxidizes just as the plating does, so it's very important you tin it the first time you use it. And once again, I DO NOT recommend filing it down.
     
  18. Metalmann

    Active Member

    Dec 8, 2012
    700
    223
    "And once again, I DO NOT recommend filing it down."



    Not on the newer types; but it's fine for the older, single wattage, irons.;)

    As the old tip gets rounded off, grinding it on a fine wheel, is what needs to be done on those oldies.

    Some of my old irons have one metal throughout, so reshaping it on a grinding wheel made it like new again.

    Then re-tin immediately.
     
    DerStrom8 likes this.
  19. trader007

    Active Member

    Feb 27, 2010
    222
    19
  20. DerStrom8

    Well-Known Member

    Feb 20, 2011
    2,428
    1,328
    You have a good point there, about the age mattering. I was judging by one of the OP's first photos, in which it appears he's using a newer iron. That is why I was saying not to file it down--they will burn out very quickly if you do that.

    As for the older ones, you can grind them down slightly as long as the wheel is very fine, otherwise you'll still get fissures and it'll burn out just like the newer ones would.
     
Loading...