[Elecraft] Magnetic soldering iron

[Tom Hammond]

Hi Ron:

>I'm building a K1, my first significant electronic project, using a 
>borrowed Weller WTCPT soldering station.  When I started trying to solder 
>a ground wire to the first of the crystal cans on the 2 band filter board, 
>I noticed the wire mysteriously moving as I approached it with the 
>soldering iron.  Further investigation revealed that the iron is 
>magnetized!  This isn't normal is it?  What should I do?

Normal? Well, it IS 'normal' for those using the WTCPT... this iron, and a 
couple similar Weller models use a ferro-magnet as the temperature sensing 
device in the tip. Then the tip is cool, the magnet exerts more 'pull' on a 
set of contacts in the base of the handle, pulling the contacts together 
and applying heat to the tip. Once the tip's up to temp, the magnetism 
'releases' a bit and the contacts open until the tip again requires heat. 
You can hear (and ofttimes feel) the contacts opening and closing as 
they're pulled closed and then allowed to open. As a result, there's a 
magnet pretty close to your work any time you're using the WTCPT.

The wire you used (probably a clipped capacitor lead, if I recall) was 
obviously tinned (possibly copper-plated) steel, rather than straight 
copper wire. When the tip of the iron got close to the wire, it was pulled 
out of position by the magnet. The answer is to run a magnet over your wire 
clippings and select those which DO NOT respond to the magnet... they're 
copper.

73,

Tom Hammond    N0SS