Re: gEDA-user: Surface mounted circuits in hobby projects

[Chris Albertson <albertson.chris@xxxxxxxxx>]

On Thu, Apr 2, 2009 at 2:13 PM, Steven Michalske <smichalske@xxxxxxxxx> wrote:


> I was soldering DE9 shells with a 15 Watt radio shack special.
> This caused me to deform most of the plastic that the pins were held
> with.
> My dad saw the results and told me that i needed a bigger iron.
> He got out the 250 Watt soldering gun and soldered each pin with out
> melting the plastic.
>
> It's because the 15 Watt iron took too long to impart enough heat to
> melt the solder, but could deliver enough heat over time to melt the
> plastic.

The "normal" way surface mount parts are soldered  is in an oven.  First solder
paste is applied to the parts of the PCB the have no solder mask. Then a machine
places each part into the paste.  The paste is sticky and holds the
part in place
then the entire board, parts ,soldr paste and all is placed in an oven
and heated
until the solder melts.  The parts are designed to withstand this kind
of treatment

It can be done this way at home.  Many people have modified toaster ovens,
some times with micro-controllers and temperature sensors.   You can buy solder
paste in a syringe.

That said I use a temperature control iron with a fine poiint conical
tip.  .01 pitch leads are easy, smaller ones take more effort.  But
what abot ball grid arrays or other parts with no access to all the
leads.   I'm seriously thinking about building a reflow oven.


-- 
=====
Chris Albertson
Redondo Beach, California


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