Homebrew PCBs

Thanks everyone for the feedback.
I am ordering the Zeph paste and the Chipquick one and some thick flux paste
too.
Both companies have good videos and info.
My goal is to develop a foolproof procedure since we have to rework over 100
12 layer PCBs each with six 208 pin 0.5mm spacing ICs for a customer.
Stencils are not practical on a populated board so that  is why I am looking
for a controlled amount of solder paste dispensing.

Henry: What are you using for the laser cut stencil material?
Bertho


-----Original Message-----
From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
On Behalf Of Henry Liu
Sent: Monday, May 09, 2011 23:04
To: Homebrew_PCBs@yahoogroups.com
Subject: Re: [Homebrew_PCBs] Re: Controlled solder paste dispensing

Using Zeph paste and a 25 gauge plastic syringe + hot air gun , I can solder
a 128 pin .5mm pitch QFP in under 10 seconds (including the pasting time)
with no bridging.

I cannot usually solder .4mm pitch devices without some bridging.  However,
I just use kester flux in a syringe and a wide soldering iron and drag it
across the pins and this moves 99% of bridges as long as I made my pcb pads
big enough.
Syringes have no cleanup.

I have a laser cutter and it's pretty effortless for me to make a stencil
but I don't use it unless I need to make more than 2 boards because the
cleanup time is more than my syringe time.