Homebrew PCBs

----- Original Message ----- 
From: "Andrew" <andrewm1973@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Saturday, August 18, 2007 1:58 AM
Subject: [Homebrew_PCBs] Re: 0.5mm pitch breakout board?


>> Leon wrote:
>> I've done one or two single-sided QFN boards for
>> accelerometers, I find it best to make one at a
>> time.
>
> Leon,
>
> How do you hold your boards one at a time ?

I don't use an etching tank, just a small plastic container in a larger one 
with some very hot water in it. I agitate by rocking the etchant container 
continuously - 5 mins with fresh FeCl3. I've got a bubble etching tank, but 
I don't like it much.

>
> The one I am using for a current project is a
> QFN28-4 that has a 0.45mm lead pitch.  I have
> droped down to 6-8 thou tracks which seems to
> be my etching limit with CuCl.

That would be more difficult.

How do you solder the QFNs? I use drag soldering, but I have got a very 
sharp point cartridge for my Metcal which might be better.

Leon
--
Leon Heller
Amateur radio call-sign G1HSM
Yaesu FT-817ND and FT-857D transceivers
Suzuki SV1000S motorcycle
leon355@...
http://www.geocities.com/leon_heller