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Oxyides on solder's and soldering iron's ?

Discussion in 'General Electronics Chat' started by DarthVolta, Sep 20, 2019.

  1. DarthVolta

    Thread Starter Member

    Jan 27, 2015
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    I get annoyed at all the solder that goes to waste keeping the tip clean, and extra flux needed. And I'm wondering if some one tried soldering in a oxygen free box, like a radiation 'hot box' full of just nitrogen. Or sealed machines, etc. Did any factories try such things ?

    I would like to see difference. How would it effect common flux too I wonder?
     
  2. jpanhalt

    Expert

    Jan 18, 2008
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    It would probably help. Inert atmospheres are used in some commercial brazing operations. I have used such chambers (glove boxes) quite a bit. Have you considered:

    1) Added cost of glove box
    2) Added cost for purified gases
    3) Inherent clumsiness for hand work
    4) Mechanical manipulators add even more cost
    5) You will still need flux

    For automated assembly solder paste is used extensively. Even some hobbyists use it now.
     
    shortbus likes this.
  3. shortbus

    Expert

    Sep 30, 2009
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    Don't forget the flux is mainly for removing the oxides on the work being soldered, so doing it in an atmosphere box it would still need flux.

    But I have a bigger question, how much solder are you using to wet and clean the soldering iron tip, that it would be a waste? Are you wiping the iron tip on a damp cloth or paper to clean it? After doing that you only need enough solder to tin or "wet" the tip, you don't add enough to make a puddle of solder on the work bench.
     
  4. nsaspook

    Expert

    Aug 27, 2009
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  5. dl324

    AAC Fanatic!

    Mar 30, 2015
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    How much solder are you using for tip cleaning? In 40 years, I haven't gone through more than a pound or two of solder and what I use to tin the tip of my iron is insignificant.

    Flux for tip cleaning? The flux in cored solder is usually sufficient. I bought a quart 2o years ago and I've probably used less than an ounce.
     
    shortbus likes this.
  6. Audioguru

    Expert

    Dec 20, 2007
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    I suspect that you are using a cheap (Chinese?) soldering iron and solder.
    A cheap iron has no temperature control or uses a simple "light dimmer circuit" so that you can turn it up or down. Then when sitting it gets hotter and hotter and hotter and hotter and incinerates the rosin and produces oxides. Lots of smoke.

    My Weller soldering iron is at least 52 years old and the same one is still made today. It heats quickly then senses its tip temperature and controls it well. The tip lasts for many years. Each solder joint made with Western Name-brand rosin-core solder takes about 1 second.
    No smoke.
     
    narkeleptk likes this.
  7. SLK001

    Senior Member

    Nov 29, 2011
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    Our plant used to reflow all our electronic boards in a nitrogen atmosphere. The solder joints that emerged were the best looking that I have seen.
     
  8. Sensacell

    Moderator

    Jun 19, 2012
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    Here's my 2 cents.

    1) Tight control of temperature is really important

    2) Solder is dirt cheap

    3) Flux is simple, cheap and works great
     
  9. shortbus

    Expert

    Sep 30, 2009
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    They didn't use a wave flux bath too?
     
  10. dl324

    AAC Fanatic!

    Mar 30, 2015
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    I don't think $25-30 per pound is dirt cheap. I liked it better when it was $7 for a one pound spool.

    I got a good price on a couple dozen spools on eBay awhile back, so I'm set for life.
     
  11. SLK001

    Senior Member

    Nov 29, 2011
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    No. The flux was in the paste that was screened on the boards.
     
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  12. shortbus

    Expert

    Sep 30, 2009
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    So then the atmosphere was just to make the joint's look better not to remove the oxides from the board and component leads?
     
  13. jpanhalt

    Expert

    Jan 18, 2008
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    I think that is right. I visited a shop once that oven brazed gears to hubs. It used an inert atmosphere as I mentioned in my post. The atmosphere per se does nothing to remove oxides, but it prevents more oxides from forming at the elevated temperature. Of course, brazing temps are a lot higher.

    Now, what if you used 20% CO2 in argon (MiG gas) or added a bit (5%) of hydrogen? I don't know what would happen and really don't care from the standpoint of the amount of soldering I will do in my remaining life.

    As I and others have pointed out, the cost of a hobbyist's solder is negligible compared to the cost and inconvenience of using a "glove box." Since the TS was wondering about reducing the amount of solder used in cleaning his soldering iron, what has not been discussed is whether the iron would still need to be cleaned of excess flux and retained oxide, even if hand soldering were done in a glove box. My untested opinion is that the iron would sill need to be cleaned.
     
  14. SLK001

    Senior Member

    Nov 29, 2011
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    That's what the flux does. You don't need an oxidizing environment to burn off the oxides if you use flux. Not only did the joints look better, but the board's reliability was much better.
     
  15. jpanhalt

    Expert

    Jan 18, 2008
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    Are you suggesting that one can use an oxidizing environment (e.g., air) and more heat instead of flux?
     
  16. shortbus

    Expert

    Sep 30, 2009
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    Not trying to be argumentative but to understand a new concept. Just never heard of using a shielding gas atmosphere to soft solder. Braze or silver solder yes, but not the soft solder.
     
  17. SLK001

    Senior Member

    Nov 29, 2011
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    I'm not an expert in soldering technology, but there probably is a temp where the oxides are removed. However, being an oxidizing environment, more oxides (and probably harder to remove) are being formed. You also have the problem that the substrate material is highly temperature sensitive and it could have burned to ashes long before the oxides are removed. The heated flux removes the oxides from the board and the nitrogen environment prevents new oxides from forming.

    With fine pitch devices, you want to prevent the solder from forming the oxides that it normally does when molten - the nitrogen does just that. When molten under nitrogen, the solder would stay bright and shiny for as long as the nitrogen was present. To better understand this problem, try to solder a component on a PCB using flux-less solder only (no flux). The solder will melt just fine, but the oxides that immediately form under higher temps will prevent the solder from free-flowing, or properly wetting all the components. Beginning solderers know this phenomenon well.
     
    shortbus likes this.
  18. shortbus

    Expert

    Sep 30, 2009
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    Thanks for the further explanation.
     
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