bill wrote:
Long time ago, pop mechanics ran an article
about making your own soldering iron by
using the carbon rod from a C cell battery
(carbon zinc cell)

http://www.coldheat.com/

They have a three-minute QVC commercial for it. It's obvious that it's
running current through the object to be soldered; they show the little
red "power" light going on and off as they touch and un-touch a solder
pad on a circuit board.

Like the Radio Shack butane unit, the device is $20 and tips are $10.
They have three different tips shown. Takes 4 AA batteries.

"This tool is appropriate for most electrical projects with wires between
18-24 gauge, small jewelry repair, and electronic projects."

"We do not recommend it for soldering of large metallic components that
require a lot of heat transfer, such as heavy gauge wire. Also be aware
that high temperatures will be created during active soldering; please
consult your component's datasheet for any special precautions needed."

"What is the spark I see sometimes during soldering?
"The spark (arc) is caused [sic] electrical current passes from one half
of the tip to the other. Although the tool's spark should not damage
any electrical or electronic components, we recommend caution when
soldering sensitive components. Also, ensure that the tool is not used
in flammable or explosive environments, such such as near gas or
gasoline fumes."

One thought that occurs to me is that it looks like a DYNAMITE tool for
desoldering with a suction device, since it appears that solder doesn't
stick to the tip it ships with. Can't speak for the other tips; they
look more metallic and are not demonstrated on the site. They recommend
wick for desoldering, but those of us not of that religion might have
an alternative.

--
"Kerry arrived in-country with a strong anti-Vietnam War bias and a self-serving
determination to build a foundation for his political future."
-- Rear Admiral Roy Hoffmann, USN (Ret.), May 4, 2004