Solder paste reflow without stencil?

Discussion in 'General Electronics Chat' started by Razor Concepts, Jun 9, 2010.

  1. Razor Concepts

    Thread Starter Senior Member

    Oct 7, 2008
    Is it feasible to do reflow with hand-applied solder paste instead of a stencil? I want to solder a adxl335 package accelerometer (no pins, just pads on bottom like QFN). It may not be ideal, but it would work good enough, right? Thanks.
  2. SgtWookie


    Jul 17, 2007
    Sure. Use a syringe with solder paste in it. You can order them online. I think they have a shelf life of about 6 months.
  3. achilez

    New Member

    Mar 23, 2010
    I'm not sure a stencil has any inherent advantages over using a syringe/dispenser type except when the number of pads that need solder is large, and there is a need to get things done quickly.

    I'm inclined to think that, for a small-pitched package like yours, a stencil might smear the paste, and that doing it manually would be more accurate (unless your hands are shaking from too much caffeine!).

    BUT I don't have any evidence to back this up, so please, those of you with layout experience, correct me if this is wrong.
  4. Tobias

    Active Member

    May 19, 2008
    I have alot more luck with a syringe than the stencils. On a PCB board with around 20 components, a few of them small pitch, I could do the syringe faster and with better results. I had problems with the solder not sticking to some pads and smearing on others. I am sure with more practice it would have gotten better yet I really took to the syringe route quickly.

    I keep my solder syringe in the freezer. Its atleast a year old and works great.