[1000mp] Using a 25W soldering iron

[Uwe Fleischer]

Hi Dick (and others of course),


You wrote:

> I am afraid to put too much heat to the board. I am using a 25 watt
> soldering iron.  Appreciate help from anyone who has done this mod.


This statement shows a possible source of problems which seems to be very
spread amongst hams. I've often seen hams who use a very low power soldering
iron, because they are afraid, that the board and the electronic components
may get too hot if they would use one with more power. Indeed, just the
opposite is the case. 

We clearly have to distinct between temperature and power. The power of the
soldering iron indicates how much temperature per time the soldering iron
can "deliver" to something that we tip on with the soldering iron. If the
power of the soldering iron is low and we tip on a large ground area, or a
soldering pad with a lot of long copper tracks connected to it, more heat
per time flows into that heat-conducting structure than the soldering iron
is able to produce. Thus the temperature of the soldering iron decreases and
we have to wait until the heat-conducting structure (copper-tracks and
electronic components) has reached almost the same temperature as the
soldering iron. At this point, the temperature of the soldering iron tip
SLOWLY increases again, until the tin is melting. This is the safest way to
let your electronic components face the hell of temperature-death.

In the beginning of my professional career, I've repaired far over a
thousand computers and peripheral equipment. It was the time, where one was
still measuring and scope-ing on the boards to find out the malfunctioning
IC and if you had a problem e.g. on the address- or data-bus, you sometimes
had to change a lot of ICs until you found out the bad one :-(

So I can claim, that if I would have got one US$ for each pin of an
electronic component, that I have soldered, I could stop working and live a
beautiful life as a professional ham. Since these days I always use a
soldering iron with at least 60W. And if a soldering iron has a temperature
adjustment, I adjust it most times fully clockwise or at least to 400°C.
Thus, most of the soldering work does not take longer than 1 or max. 2
seconds per pin. Some times 3 or 4 seconds, if you have to solder one end of
a coil with a thicker wire to a ground plane.

If you ask me, a 25W soldering iron is totally unsuitable for the work, we
hams usually do.


73 de Uwe, DL8UF