Solder Paste Storage

Discussion in 'General Electronics Chat' started by mwalden824, Jan 26, 2013.

  1. mwalden824

    Thread Starter Member

    Mar 6, 2011
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    Hi. I have a quick question. I bought some solder paste a few months ago, and it did not say anywhere on the package to store it in a freezer or refrigerator, so I didn't. I haven't used or opened it yet, and it has been at room temperature for approximately 3 months. I have just now put it in my freezer. It is a syringe of 63/37.

    I was just wondering do you think it will still be usable? I guess it would depend on the type of solder paste, but I can't find a datasheet or any reference material for this brand that I ordered. I do know now that all pastes eventually go bad and become less effective. But was just wondering and making sure I should store this in the freezer or refrigerator as soon as I buy it in the future correct? Which one would make it last longer? The freezer I assume? Also, do I wait until I open it to store it like this or do I do it immediately?

    I was planning on using it right away, but ran into some problems on my project and other unrelated issues. So it will still be a few weeks before I actually use it.

    I've tried searching everywhere for answers to these particular questions but for some reason I can't find much. Maybe I am just wording my searches wrong.

    Thanks in advance for any help,
    Michael Walden
    Senior Electrical Engineering Student
    University of South Alabama
     
  2. MrChips

    Moderator

    Oct 2, 2009
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    Why would you want to buy solder paste for electronics use?
     
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  3. mwalden824

    Thread Starter Member

    Mar 6, 2011
    51
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    I'm going to be ordering boards soon with very tiny components, I just figured it would be easier to get a stencil laser cut and stencil the paste onto the board and place the components by hand and use a hot air gun to re-flow. I plan on using the smallest components possible so my board will be light weight and small for my project which isn't absolutely necessary, but just something I would like and it would help the design.

    Or do you know of any services that will assemble boards in low quantities for reasonable prices? Or any other method that might be easier or less time consuming or whatever? I would think this wouldn't be that hard or am I wrong?

    Thanks for your help,
    Michael Walden
    Senior Electrical Engineering Student
    University of South Alabama
     
  4. nerdegutta

    Moderator

    Dec 15, 2009
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    Wouldn't these small components blow away?

    I recently got hold of some solderpaste that had expired. I think it was stored in a fridge. I place a little needle head size paste on one side of the pad, place the component, and "tack" it in place with a soldering iron. I don't even have to touch the component. The coppertrack transfer the heat.

    Smallest size, isn't that 04 something...? I'm soldering 0805.
     
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  5. t06afre

    AAC Fanatic!

    May 11, 2009
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    They name it solder paste. But it is not the same as traditional solder paste. It is a homogenous mixture of a solder powder and flux. It is used for SMD soldering.
    @Nerdegutta it is no problem using hot air on SMD. I have done it a lot. After some training it is easy to get it right.
    @Michael Unless you have access to hot air oven. I would not have used a stencil. For the beginner it is easy to smear the paste out during work. And it can be a mess to clean up. So just put paste on one component at a time, then solder it. It is somewhat more easy if you just have to place components and then just whack it in oven
     
    Last edited: Jan 26, 2013
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  6. Markd77

    Senior Member

    Sep 7, 2009
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    Just give it a try. If you happen to have some stripboard around then put a few resistors on. It's useful practice to see how much paste you need and how to heat it.
    I suspect it will be OK.
    I just transfer small blobs of paste to the PCB with a wooden toothpick, place the components with tweezers and then heat the whole board on a hotplate, but obviously that only works for single sided boards.
    On a side note, I believe it's possible to DIY the stencils the same way the professionals do it. You just need to find a source of the thin photosensitive plastic and then it's just the same as UV etching a PCB.
     
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  7. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    Just put a bit down and heat it with the hot air.. If it balls up (play solder soccer) its more than likely just fine to use. Some require a fridge while others do not.
     
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  8. mwalden824

    Thread Starter Member

    Mar 6, 2011
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    Awesome, thanks for everyone's input and advice. Quick question though. What exactly is "traditional solder paste?" I've never heard of it. What is it used for? I guess that was the cause for the confusion in the first few posts, but I just wasn't aware there were different types.
     
  9. MrChips

    Moderator

    Oct 2, 2009
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    Sorry. The solder paste I though you were referring to is the flux paste you dab on the copper plumbing before brazing with a propane torch.
     
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  10. atferrari

    AAC Fanatic!

    Jan 6, 2004
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    Hola t06,

    If it is not taken as derailing this thread (which it is :p) could you describe what you use and how you do it? Thinking of starting with hot air in the near future.
     
  11. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    Copper plumbing pipe and a propane torch? That's how I do all my SMD soldering... ;)
     
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  12. t06afre

    AAC Fanatic!

    May 11, 2009
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    I have used hot air rework stations from Weller. They do not come cheap. For soldering small components up to SO16 I just use a nozzle and spray the component with hot air. The quite cool thing is you that you do not have to take much care about the component alignment. The surface tension in the molten solder. Will adjust the component into a perfect fit on the pad(s)
     
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  13. mwalden824

    Thread Starter Member

    Mar 6, 2011
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    Hey, I have another question. I already asked this earlier in this thread, but no one responded. I probably should have started a new thread.

    Anyway, does anyone know of any good services that will assemble your boards for you? I've searched and found a few but just wanted to know if anyone here has tried any of these services on a small scale. If so, could you recommend a place?

    It would be nice if there is an all-in-one service where you can get your boards made and assembled. I'm sure they exist, but I can't seem to find any. I have found many circuit board small scale services, and a few assembly services, but nothing all in one.

    It's not that I mind assembling the boards myself, but if I wanted quite a few boards it would become a pain. Also, things like large BGA packages for FPGAs, CPLDs, etc. would be very difficult to properly solder I would imagine.

    So if anyone knows of any services like this, please let me know.
     
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