[TriEmbed] Solder paste dispenser

[Brian]

On 9/25/18 8:19 AM, alex--- via TriEmbed wrote:
> - brute force; cheap but wears out your hand

I'm guessing you mean the small syringe style of dispenser, like what 
Chip-Quik comes in?

If you find operating the plunger to be too fatiguing at room 
temperature, try immersing the dispenser (properly sealed, of course) in 
a hot water bath for 10 minutes or so.  Flux viscosity drops rapidly as 
temperature increases.

I definitely recommend going the stencil route if you're placing more 
than a few parts.  Steel stencils aren't that expensive these days; OSH 
Stencils (https://ohsstencils.com) offers stainless steel stencils in a 
variety of thicknesses for less than $2/sq-in.  There's really no need 
for an alignment jig; all you need is a flat surface and some blue (or 
green) painter's tape.  Tape the PCB to the surface, align the stencil 
by hand, and tape it down along one edge (so you have a hinge, 
essentially).  If the stencil is larger than the PCB, tape waste PCBs 
around it to provide a level surface for the stencil (OSH includes 
laser-cut L-shaped acrylic frame pieces in every order for just this 
purpose).  Also, a little misalignment won't kill you, especially if 
your board has a proper solder mask; the solder will strongly prefer the 
unmasked copper, and minor misalignments will clean themselves up just 
through surface tension.  You might have to do a little clean-up with 
some braid and a soldering iron, but you were gonna do that anyway, 
right? :o)

Happy reflowing!

-Brian