Why my guitar wire gets very hot ?

[mattduvall]

EASY problem

ok all i know about electronics is what i learned in my high school physics class last year. I need to cut pieces of foam, but a cutter the size i need is very expensive, so i tried to make my own.

So heres my problem, when i connect the circuit, the guitar wire gets very hot, but only for a few seconds, then it is just warm or room temp. when i disconnect it and wait a few minutes it does the same thing. Also i cannot just disconnect it then connect it again, i have to wait a minute or 2. here is a picture of my setup.

Any help is very much appreciated

 

[Externet]

Re: EASY problem

The battery you are using is the wrong power source for the wire; or does not have the watts-hour capability; needs to chemically recover itself for a few minutes after delivering all it can deliver for a few seconds.

A better option could be a less voltage power supply and capable of more current, or Watts. Something like 1 volt at 20 Amperes by guessing. The exact values are to be tried by reaching the needed temperature of the wire and not more.

Measure voltage, current and temperature and make a chart.
If you can only use 12V, connect a 12V light bulb in series and check it the temperature reaches your needs to cut foam. The thickness and lenght of the hot wire has a lot to do with the success. If it is from a guitar, meaning a couple of feet, you must lower the voltage and increase the current capability of the power supply.

 

[keith1200rs]

EASY problem

The other possibility is the wire resistance increases when it gets hot so the current drops. If this is the case then a constant current drive may help, or a simple adjustable drive so you can increase the voltage as the wire heats up.

Keith