Re: [uCsimm] Soldering, was: RTL Port, actually RTAI.

From: Egil Kvaleberg (
Date: Wed Jan 19 2000 - 07:21:54 EST

On Wed, 19 Jan 2000, you wrote:

> For the actual soldering, I put the soldering iron onto the pads, touching
> the pins from the side:
> |-------
> soldering========= ,--| chip body
> iron ========= / |-------
> ========= pin /
> =========----------'
> ---------------------------- pad
> and then sliding the soldering iron slowly along the pins. It makes
> a small noise when arriving at a new pin and then you see on top of
> the pin a small shiny convex surface coming up. That's the time
> to move to the next pin.

Agreed, this is definitely the better technique. You might need to add
some floating flux from time to time.

Another piece of equipment that is really of essence, IMHO, is a stereo
microscope. There are perfectly OK ones available at approx $200 a piece,
they are more than good enough. Avoid anything that hasn't got built in
illumination, it can be wortwhile to invest extra in dual fiber type

The only real problems with these inexpensive units is that the maximum
board size is limited due to the shallow reach of the base.

Nikon, Zeiss or Bausch&Lomb units are nice, of course, but definetely OTT
for occasional use.

Do not get carried away wrt. to magnification, somewhere between 10X and
20X is OK.

Another common misunderstanding: You don't need a tiny iron to do SMT.
What you do need is a very tiny tip, 0.4mm across for QFP and 0204, 0.8mm
across for coarser work. They get blunt after a while, so be prepared to
change them frequently. Temperature control is essential, of course.

Having used a long range of various fancy "SMT irons" in my time, my
conclusion is that the good old Weller 50W unit is my preferred tool.


Email:  Voice: +47 22523641, 92022780 Fax: +47 22525899
Mail:  Egil Kvaleberg, Husebybakken 14A, 0379 Oslo, Norway

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