Homebrew PCBs

Most of the professional glue is heat cure and won't dry in the air.
So if you don't already have an oven set up to do SMT and a wave
solder machine with a chip wave, the glue won't do you any better.

In general, even if you are doing a 2 sided board, the cohesion of the
molten solder between the part and the board is enough to hold
virtually all parts on the bottom of the board from coming off during
re-flow.  Just don't knock the board while the solder is still molten!
Otherwise you'll be picking up parts for weeks.

If you are having problem with chips falling off on the bottom side of
your board when you re-flow the second side, I'd understand the need
for a small drop of glue.  But in general, only if you are wave
soldering the bottom side do you need to glue the parts on.

On Thu, Jul 30, 2009 at 9:30 AM, Stefan Trethan<stefan_trethan@...> wrote:
> Generally speaking, SMD components only really need to be glued down
> for wave soldering.
>
> I recommend that you look into using solder paste and a reflow process
> (hotplate, ofen, hot air), you will find it superior and faster than
> manual soldering with an iron, and the components will usually align
> very well.
>
> If you still want to glue them down, maybe you can find professional
> SMD glue, sometimes small quantities are sold in a syringe. I've seen
> it on Ebay shipping worldwide from china if there is no local source.
>
> Which leads to the next suggestion, buy or build a pneumatic
> dispenser. With this (and a suitable blunt needle on the syringe) you
> can make very nice consistent glue dots on your board, it is also very
> fast. You can use the same system to dispense solder paste.
>
> ST

-- 
Erik L. Knise
Pacific Shipping Company
Seattle, WA