Maplin have a temp. controlled soldering iron in their Xmas bargain list for
?30 - a big discount, don't ask me how I know- for all those in the market
for one. It's fully isolated by transformer with an earth connection at the
rear. Good value !
Geoff.
----- Original Message -----
From: "Tony Duell" <ard_at_p850ug1.demon.co.uk>
To: <cctalk_at_classiccmp.org>
Sent: Thursday, November 13, 2003 11:19 PM
Subject: Re: Cheap pseudo temp. controlled soldering (was: Spending)
> >
> > Regarding temperature controlled soldering irons: if you don't want
> > to, or can't, spend the money on a temperature controlled soldering
> > iron, a light socket and a variety of edison-base incandescent light
> > bulbs in various wattage ratings, to insert as needed, in series with
> > a soldering iron might help. :-)
>
> This trick (or the similar one of using a tirac-based 'dimmer switch' in
> series with the soldering iron) is well-known to UK modelmakers who want
> to solder 'white metal' kits. I am not sure what the US name for 'white
> metal' is, it's a low-melting-point lead alloy...
>
> However, for electronic work, this is nowhere near as good as a real
> temperature controlled iron. Consider the normal 15W iron sold to
> hobbyists. It's designed to run at just above soldering temperatures with
> the bit in free air. Now, if you put a significant 'load' on the bit (say
> an IC pin soldered to a ground plane in a PCB), then the temperature of
> the bit drops. The result, if you're soldering, is a dry joint. If you're
> desoldering, it's a ruined IC, PCB, or both due to the amount of time you
> hold the iron on the joint to melt the solder.
>
> What you need is a higher power iron for this application, but such an
> iron would normally get far too hot.
>
> Now consider the temperature-controller, thermostatic, iron. The one I
> use is something like 50W. When the tip is in free air, the element is
> only swithced on for part of the time, so the mean power is probably
> something like 15W. But if you put the tip on said IC pin on the ground
> plane, then the element is turned on for a greater proportion of the
> time. The mean power goes up as you'd want.
>
> -tony
Received on Fri Nov 14 2003 - 01:41:55 GMT