Solder paste use

Discussion in 'General Electronics Chat' started by Shagas, Oct 23, 2013.

  1. Shagas

    Thread Starter Active Member

    May 13, 2013
    802
    74
    This has been bugging me lately :

    DSC_0108[1].jpg

    The picture is bad quality (and so is the lettering) so I'll write it out:

    **************

    SOLDER PASTE
    for soldering and tinning.

    *red lettering*

    This solder paste is not suitable for the soldering point on Integrated Circuit of high voltage (frequency/power). You are suggested to clean the soldering point y ethyl alcohol after using in order to avoid the possible short situation.

    *************

    - Why is it not suitable for Ic soldering of high voltage/frequency?
    - Why is there is a risk of possible short? I've tested the paste with my DMM set on 20Mohm range and I can get absolutely no conductivity out of it in 'solid' or liquid form whatsoever , so what's the deal?


    Does the paste exhibit capacitive properties at high frequencies/votages?

    It's the paste that looks like engine grease without the colour of engine grease (no solder in it)
     
  2. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    7,386
    1,605
    This "solder paste" is non conductive? WTF is it made of?
     
  3. ronv

    AAC Fanatic!

    Nov 12, 2008
    3,281
    1,232
    I think it is flux - perhaps acid type flux.
     
  4. Shagas

    Thread Starter Active Member

    May 13, 2013
    802
    74
    It's not the kind of paste with solder in it , it's just an acid type flux thing as ronv mentioned. I mentioned that it has no solder in it.Looks like vaseline
     
  5. Shagas

    Thread Starter Active Member

    May 13, 2013
    802
    74
    DSC_0111[1].jpg

    like this
     
  6. DerStrom8

    Well-Known Member

    Feb 20, 2011
    2,428
    1,328
    putting an ohmmeter in solder paste would rarely get you a good conduction. Sodler paste is simply made of tiny particles of lead/tin (solder) mixed in with flux. When the paste is used for soldering, the heat burns away the flux and melts the solder to the pad. I'm not sure if that's what you have though, since usually REAL solder paste is more of a gray-ish color than white. I would suggest it's supposed to be used like glue to stick your components to the board, except that it says it's to be used for soldering and tinning. Try dipping the tip of your soldering iron into it while it's hot and see if it gives you a silvery coating. It's possible the ratio of flux to solder is much higher than the stuff I've seen, so it appears more white? Just pulling thoughts out of thin air here....
     
  7. ronv

    AAC Fanatic!

    Nov 12, 2008
    3,281
    1,232
    :rolleyes:You guys are just to young to know about flux.
     
  8. DerStrom8

    Well-Known Member

    Feb 20, 2011
    2,428
    1,328
    Who doesn't know about flux? :confused:

    I simply haven't heard of plain flux being called "solder paste"
     
  9. ronv

    AAC Fanatic!

    Nov 12, 2008
    3,281
    1,232
    DerStrom8 likes this.
  10. DerStrom8

    Well-Known Member

    Feb 20, 2011
    2,428
    1,328
    Oh, I didn't even think of that implication. I was just surprised that someone that contributed to this thread didn't know what flux was :p

    Makes a lot more sense now though. I generally use the rosin core solder myself, though sometimes I need real flux instead for certain projects.

    Matt
     
  11. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    5,435
    1,305
    It's an old name for soldering flux, from the days before we had actual solder paste.
     
  12. Shagas

    Thread Starter Active Member

    May 13, 2013
    802
    74
    So It seems that I have in front of me an ancient product :)
    Anyone have an explanation as to why the label says that there is a possibility of a short and that it can't be used for high freq/voltages ?
     
  13. DerStrom8

    Well-Known Member

    Feb 20, 2011
    2,428
    1,328
    Heh, I always heard it called "flux", long before modern "solder paste" appeared :p
     
  14. shortbus

    AAC Fanatic!

    Sep 30, 2009
    4,000
    1,512
    Some fluxes, even the ones used for electronics are conductive or semiconductive after use, not like a semiconductor though. Most all production made boards go through a "wash" cycle after being soldered, to remove the flux residue.
     
  15. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    7,386
    1,605
    Excepting those that use "no clean" flux. :cool:
     
  16. Shagas

    Thread Starter Active Member

    May 13, 2013
    802
    74
    Yes that's what I thought initially , that's why I tested the conductance before and after using it (even in molten form) and found none , that's why I made this thread.

    Yeah the best answer is probably : "just... clean the damn thing after you finish soldering "
    but I was just looking for an explanation .
     
  17. RichardO

    Well-Known Member

    May 4, 2013
    1,228
    382
    I would worry that this is an acid based flux suitable for soldering plumbing pipes and ducts but NOT to be used for electronic soldering. Using this kind of flux would be akin to using acid core solder in an electronic circuit.
     
  18. paulktreg

    Distinguished Member

    Jun 2, 2008
    609
    120
    Your DMM measures resistance at a few volts DC. Use a 500V insulation tester and things may be different?
     
  19. Shagas

    Thread Starter Active Member

    May 13, 2013
    802
    74
    I understand , In any case it looks like there is nothing to worry about with 5 volt circuits .
    Still i'll probably be looking into some other form of flux .
     
  20. ronv

    AAC Fanatic!

    Nov 12, 2008
    3,281
    1,232
    I think the problem comes from corrosion which may take quite a while to show up.
     
    Shagas likes this.
Loading...