According to jim rozen :
In article , Boris Mohar says...

Yes. Weller tips cycle the mechanical switch in the handle. Metcal tips use
curie point to continuously affect the amount of absorbed RF energy.

The weller tips also use the curie point, but as you say to
affect the switch in the handle.

I work with a *lot* of MOS and otherwise static sensitive devices,
and I've never had one of the weller irons like that cause a problem.
In fact they're my preferred iron, the variable temp weller ones
just don't last more than a year, and I don't like the 'feel'
of the metcal ones.

The handle's just not 'right.'

Hmm ... my own favorite for variable temperature and tiny
workpieces used to be the Edsyn "Loner" -- but those seem to have
vanished from the list of available ones.

Now, I use either of two PACE units -- one is a portable one
which will run from 12 VDC or the AC line, and which contains a tiny DC
vacuum pump for the solder-sucking functions. The other is a dual
station -- one solder sucking, and one for just direct soldering. That
one is rather less portable.

Enjoy,
DoN.
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