We recently got a question about what to use as a power supply (read below for why this could be a deadly mistake):
“My question is what if I were to use a digital soldering iron as my supply. If I were to use the wire from the supply to the cutting wire I could control the temp depending on what type of foam and the length of wire (or gauge). This is my idea and I’m not sure whether it is a good one or not. What do you think?”
Here’s our answer:
After some thought Bob actually recommends NOT using the soldering iron as a power supply.
While the soldering iron may work, the output on it is probably AC power, not DC power.
** And AC POWER CAN BE DEADLY! **
It’s unlikely that the soldering iron’s output is deadly, but why risk it?
From Bob: “I would be very cautious about using a power source that involves alternating current… AC is much more dangerous than direct current like you get from a battery charger or large model
train power pack.”
So why not use a battery charger like this one from Amazon.com:
With this, Bob uses a block of wood with screws in either end, like
this (sorry for the crude diagram here!):
|| || <-- screws
| | <-- wood
One screw gets the positive (+) alligator clip from the charger, the other screw gets the negative (-) alligator clip from the charger.
Then treat the screws like terminals of a battery. One wire with alligator clips attaches from the positive screw to one end of your cutting wire. A second wire with alligator clips on each end attaches
from the negative screw to the opposite end of your cutting wire — with enough space between the two for the block of foam you’re cutting.
Be very careful, because this makes the wire rather hot — you should wait pretty much until the last second before you attach the second alligator clip to your cutting wire, and as soon as the wire is out of the foam you should disconnect at least one of the alligator clips from the cutting wire.
There is a full demonstration of this in the video we sell.