Homebrew PCBs

I've soldered a couple of qfn's by simply laying a 'sausage' of solder
paste in a line across all the pads, and then reflowing in an old
frying pan on my gas stove, and it worked fine! The sausage would have
been around 0.5mm thick, I tihnk (my paste came in a syringe-type
dispenser). With this amount the solder will happily flow onto the
pads, the part should align itself, and I didnt have any problems with
shorts.

There is some good info on diy reflow soldering here:
http://www.sparkfun.com/commerce/tutorial_info.php?tutorials_id=59
http://www.sparkfun.com/commerce/tutorial_info.php?tutorials_id=58

The quantity of paste is defined by the size of the hole in the
stencil, and the thickness of the stencil. Check the ic manufacturer's
datasheets. Here is a random datasheet from TI for a QFN-48, it
specifies the dimensions of the holes and the thickness of the stencil
(2nd last page):
http://focus.ti.com/lit/ds/symlink/tps65010.pdf


On Fri, Jan 16, 2009 at 11:28 AM, Mark Lerman <mlerman@...> wrote:
> I'm working with some QFN leadless components and I want to make
> solder paste stencils to apply solder paste before putting them in my
> toaster oven reflow solderer. I want to just drill holes in some very
> thin (.008) laminate and align it with 000 screws, then smear solder
> paste over it with a flat blade. Does anyone have any guidelines for
> volume of solder paste for various size ic contacts? Thanks for any
> links or advice!
>
> Mark
>
>