Homebrew PCBs

Hello group.

I was wondering if anyone here has attempted home reflow 
(toaster/hotplate) soldering of a fine pitch device on a non-
soldermasked board? All comments appreciated.

regards,
Art

Works fine.
For some very fine pitch components it is even recommended to go
without mask between pins.

The only difficulty is traces between pads, you may get shorts between
them and pins sometimes which you have to clear manually after reflow.
But most of the time even that works without problem.
Another thing to watch out for is component self-alignment. When the
solder is molten the component "swims" on it aligning itself to the
position with lowest surface tension (usually centered). If you attach
traces or ground planes in unlucky spots the position with lowest
surface tension might be shifted misaligning your component. This can
however be avoided easily by connecting traces to the ends of pads
rather than the sides.

ST

On Nov 12, 2007 8:55 AM, art_lammoglia <art_lammoglia@...> wrote:
> Hello group.
>
> I was wondering if anyone here has attempted home reflow
> (toaster/hotplate) soldering of a fine pitch device on a non-
> soldermasked board? All comments appreciated.
>
> regards,
> Art
>
>
>
> Be sure to visit the group home and check for new Links, Files, and Photos:
> http://groups.yahoo.com/group/Homebrew_PCBs
> Yahoo! Groups Links
>
>
>
>
>

"art_lammoglia" <art_lammoglia@...> writes:
> I was wondering if anyone here has attempted home reflow
> (toaster/hotplate) soldering of a fine pitch device on a non-
> soldermasked board? All comments appreciated.

I do 0.5mm pitch without mask on a hotplate.  At that fine a pitch,
the mask doesn't really help much anyway.  Just use some solder wick
if there are any shorts.

I've also done some tiny QFN parts that way, but I don't recall the
pitch (they were for a friend).

Even on boards I've done through fab houses, the pins are often too
close together to put mask between them anyway.

Getting the right amount of paste on the pads is somewhat important,
and if you can ensure the paste doesn't bridge the pads, it helps keep
the solder from bridging.  I use a sharpened toothpick between pads to
wipe out any bridging paste..