The temperature is regulated via a rather elegant (I think)
implementation in the iron. At the base of each tip, there's a slug
of a ferromagnetic material. The properties of this slug are
controlled during manufacture, so that it will change from a magnetic
to a nonmagnetic state at a specific temperature (e.g. 700 F).

Inside the shaft of the iron there is a switch with a magnet on the
end. When the tip is below its transition temperature, the magnet is
attracted to the ferromagnetic slug on the back of the tip, the switch
is pulled forwards, the contacts close, and current flows through the
iron's heating coils. When the tip reaches its desired temperature
the ferromagnetic slug becomes non-magnetic, the magnet in the shaft
"loses its grip", the switch is pulled backwards by a spring, the
contacts open, and the current to the heating coil is interrupted.
You can hear (and feel) a gentle "thick" when the magnet switch pops
back and forth.

I've heard this sort of Iron referred to as a "Curie Point" Iron. Is this
the same thing?

Bob Stephens

In article ,
Bob Stephens wrote:

I've heard this sort of Iron referred to as a "Curie Point" Iron. Is this
the same thing?

Probably so. A material's Curie point (or temperature) is the
temperature at which, when heated, the material ceases to be able to
support/retain a magnetic field, and any existing magnetic field is
randomized.

Heating a permanent magnet above its Curie temperature demagnetizes it.

The slugs used in the Weller tips have Curie temperatures of 600, 700,
or 800 degrees F (plus or minus a bit, I imagine).

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

In article ,
Bob Stephens wrote:

I've heard this sort of Iron referred to as a "Curie Point" Iron. Is this
the same thing?

Probably so. A material's Curie point (or temperature) is the
temperature at which, when heated, the material ceases to be able to
support/retain a magnetic field, and any existing magnetic field is
randomized.

Heating a permanent magnet above its Curie temperature demagnetizes it.

The slugs used in the Weller tips have Curie temperatures of 600, 700,
or 800 degrees F (plus or minus a bit, I imagine).

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!