resistance soldering

i have a cold heat solder iron and some normal solder irons, can i make a bigger homemade cold heat? if i can hom many amps power supply and at what voltage should i use. for the electrodes for it can i just use #12 or 14 solid coper wire?

 

Here's an article on how they work:
http://science.howstuffworks.com/cold-heat.htm

In my opinion, it wouldn't really be practical for someone to try to make a larger one at home.

If you try to use solid copper wire and high current, you will most likely fry whatever components you're trying to solder.

Weller makes, or used to make, soldering "guns" that used high AC current to heat a copper tip. These are not recommended for soldering electronic components, but I knew people who did. I personally would not use one for such purpose.