(Soldering) how is he doing this?

Discussion in 'General Electronics Chat' started by wannaBinventor, Aug 24, 2010.

  1. wannaBinventor

    Thread Starter Member

    Apr 8, 2010
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    I kinda suck at soldering. I'm not sure if I have the right equipment (radio shak iron with a kida fat tip, some thin soldering wire, and some flux), but either way I need to figure out how to solder a TSSOP package that I have gotten from microchip. (Free sample of the MRF49XA). I turned to youtube and found this video of some one just dragging an iron across the pins of an SOIC and soldering it perfectly. What do I need to be able to do this with that TSSOP?

    See about 15 seconds to 1 minute on this video. It looks like he just has a felt tip "marker" full of flux and just drags as iron I guess with some solder melted to the tip accross the pins.

    http://www.youtube.com/watch?v=Ql6Vkw5wswU&feature=related

    Any general advice on soldering a TSSOP package?
     
    Last edited: Aug 24, 2010
  2. tom66

    Senior Member

    May 9, 2009
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  3. Wendy

    Moderator

    Mar 24, 2008
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    There is no substitute for practice. He makes it look easy, it isn't.
     
  4. wannaBinventor

    Thread Starter Member

    Apr 8, 2010
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    Thanks for that.

    Looking at other videos, it seems like the reflow method is just too easy not to use. It seems like you just dab the tiniest amount of paste onto each pad, set the component, heat, and bam, components soldered. It seems like it always stays in place on the pad, without having to play games with your soldering iron. I think I've heard people talk about how bad it is for your components, but I just saw a guy on youtube that was talking about doing it for all his components.

    Bill:
    I'd love to practice on something before I mess up all my free samples, lol. I guess I'll just have to get the theory down so maybe of the three transceivers I have I'll only ruin one and have two left to talk to each other, lol.
     
    Last edited: Aug 24, 2010
  5. Wendy

    Moderator

    Mar 24, 2008
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    A fine point temperature controlled tip is critical for the process. The flux is a major help, it will make the solder stick the the metal as shown. It isn't necessary, but it helps.
     
  6. tom66

    Senior Member

    May 9, 2009
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    @Bill: From what I've heard it's not critical to get the finest point except for 0603 components. For TQFP-44, you can solder them down with a relatively fat point. But it *has* to be temperature controlled, or you will overheat your IC.
     
  7. marshallf3

    Well-Known Member

    Jul 26, 2010
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    Yoou might be able to clean up the parts you've already blobbed solder on with some desoldering braid.

    When it comes to surface mount components nothing beats solder paste, even if you're using an iron.

    I'm about out and Mouser doesn't seem to sell the small tubes of it anymore, where are people buying it nowadays?
     
  8. jbeng

    Member

    Sep 10, 2006
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    Digi-Key has it in syringes
     
  9. marshallf3

    Well-Known Member

    Jul 26, 2010
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    Thanks, I've got something to order from Jameco fairly soon so I'll see if they also have it. I have a tendency to let parts orders build up then, unless theres a great price difference, order everything from one just so I only pay one shipping charge.

    Nope, but MCM Electronics does and I've got something I need from them as well.
     
    Last edited: Aug 24, 2010
  10. Markd77

    Senior Member

    Sep 7, 2009
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    Desolder braid is amazing for when you get too much solder in there and it bridges pins. Just put the braid down with the iron on top then the second you feel it melting move the braid and iron away together - perfect joins.
     
  11. marshallf3

    Well-Known Member

    Jul 26, 2010
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    No shop should be without at least one small roll of the medium size.

    I can also attest to the fact that this stuff really works. It's been around for years and is a great low-volume alternative for SMD remork where multi-pin devices are present:

    http://www.chipquikinc.com/
     
  12. Audioguru

    New Member

    Dec 20, 2007
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    A non-temperature controlled soldering iron is usually much too hot so it quickly vapourises the important rosin and the tip is always covered with burnt stuff.
     
  13. wannaBinventor

    Thread Starter Member

    Apr 8, 2010
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    Sounds like good advice on the new iorn. I've sunk more money into this hobby that I would have liked to (I'm the cheapest person you'll ever meet), but it seems like I'm going to have to break down and get a good iron. I actually bought this one from Rshak because I think I read somewhere that its best to have one that's extremely hot. The tip is black btw. It has been that way almost since I started using it.

    With the adjustable iron, do you just set it so its juuuuust hot enough to melt the solder on contact?

    I ordered some braid, paste in a syringe, and my copper boards so I can start printing the circuits with some CAD software and doing the whole toner transfer thing.
    I think I'm going to try the PCB, solder paste, griddle, and hot air gun method first and see what happens.
    Since this will be my first time using this radio transceiver, will there be a good way of knowing if its not working because I've failed to initialize it properly vs. just having cooked the chip to the point of inoperability?
     
  14. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    Man.. I need that Flux.
    When I use my flux, and if I drag my iron, I get jumpers in hard to reach area between pins :eek:.

    Any one knows the part no for those.
     
  15. Audioguru

    New Member

    Dec 20, 2007
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    I have a Weller temperature-controlled soldering iron that is about 44 years old and it still works like new. They still make the same one.
    Its temperature is fixed by the temperature selection of its tip. I use a 700 degrees F tip.

    A cheap soldering iron gets hotter and hotter and hotter and hotter until the tinning on its tip is oxidized and the same with any flux on the item being soldered.
     
  16. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    Drag soldering is done with a special tip that has a conical bowl to allow the solder to sit in. A regular soldering tip will not work like that.
     
  17. marshallf3

    Well-Known Member

    Jul 26, 2010
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    My two main Weller's are about 18 years old and temperature controlled. They are still made and still fairly reasonably priced for what you get. Look up the Weller model WLC100

    Only had to replace one tip during their life and that's because it got badly bent by an associate. I don't know what he was doing, I've used them to pry off shields I was desoldering and the tips are tough as iron - probably because that's what the base metal is. I don't know what they're coated with but it wipes clean with a damp sponge and they make about a dozen different tips for them.
     
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