"Cold heat" soldering?

[John Foust]

I'd seen the commercials for this instant-on battery-powered
soldering iron and wondered if I should add it to my tool box.

I saw this FAQ on Thinkgeek:

http://www.thinkgeek.com/files/FAQ040504.pdf

which made me think twice:

Q: What kind of soldering projects is this tool recommended for?
A: Based on the specifications mentioned above, we recommend this 
tool for most electrical projects (such as wires 18-24 AWG), small 
jewelry repair, and larger electronic projects. We do not recommend 
it for soldering of large metallic components that require a lot 
of heat transfer or for soldering sensitive electronic components 
that may be damaged by fast-rising temperatures or high electrical 
current. (Momentary high-amperage current will be created during 
active soldering.)

Q: What is the spark I see sometimes during soldering?
A: The spark (arc) is caused by the passing of electrical current from 
one half of the tip to the other. Although in testing the tool’s spark 
did 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.

- John