Homebrew PCBs

David Griffith wrote:
>  
> 
> 
> Does anyone here have any pointers on making a board with a QFN packaged
> device and then hand soldering it? I'm pondering doing something like
> putting a lot of relatively large vias underneath to made a connection
> with the thermal pad on the bottom. At first I thought that I might get
> away with using heat sink grease, but it looks like that thermal pad is
> the only connection for Vss.

The best method I found is to lay the PCB on a electric hotplate until 
it reaches around 120C~150C surface temperature. Use glass cloth under 
the PCB to avoid local hot spots. Then apply a adjustable hot air gun 
directly over the QFN IC will melt the solder quite quickly. Use plenty 
of liquid rosin flux. The hotplate I use is a cheap $30 domestic thing.
Once I was debugging a circuit and removed and re-soldered a 64 pin QFN 
about 5 times using this method.