Homebrew PCBs

Yeah I've done the same- 'cept that my 're-flow- oven is a way crappy
toaster oven that has the poorest temp control right now- I am working
towards correcting that but is on backburner indefinately while I
finish up other projects.,, I've also used my conventional oven a long
while ago- untill I started thinking about the consequences...

 Hey- I wanted to ask DJ,, is your r8c programmer a home built? i am
looking for such a design as I canot afford to buy one at the moment....?

 QFN,, these days I if I am doing a proto with these packages,, (ie,
just did a bunch of MMA7260Q 3 axix accell breakouts), ratherthan
firing up the ol' toaster, I do them by hand- what I try to do is plan
the package footprint (or layout) for that in advance by extending the
pads outwards a bit so as to have something to 'tack' to with the iron
rather than having the pads hidden underneath the package itself.
Typically for a 'flag', I will attach one of the gnd pads to it in the
footprint or layout and secure the flag via the gnd pad (not robust
but works), and also heat up the flag if possible by touching the iron
to the underside on the bottom layer(or opposite PCB layer, that is)-
plan ahead for this and tin the flag nicely or use solder paste-
whichever you use. Liquid flux is very handy to use for these
situations because it will get right under there without problem and
greatly aid in the 'speading' of whatever solder materials are
there....(cut it 1:1 with alcohol to thin it out, dump it into a tiny
syringe and off you go...)

m2c,, cheers, jd

--- In Homebrew_PCBs@yahoogroups.com, DJ Delorie <dj@...> wrote:
>
> 
> "Leon" <leon355@...> writes:
> > How do you solder the QFNs?
> 
> A couple of weeks ago we had a gEDA meeting here, and I reflowed some
> QFNs on my hotplate.  Two power supply boards, two worked!  These were
> 0.5mm too, with a thermal pad.
> 
> http://www.delorie.com/pcb/hotplate/
> 
> Example reflowed board:
> 
> http://www.delorie.com/house/furnace/pcb2/
>