My requirement was to bend a piece of acrylic plastic 24 inch long by 0.093 inch thick. My first attempt I used the 32 AWG wire, it got warm ~200 degrees F. So I did some math (29.5 Ohms at 1.84 AMPs would require 54 volts to get to 1200 degrees). If I did the math first, it would have told me that the 22 AWG wire that is 24 inches long and has 1.31 Ohms per foot would be ~2.62 Ohms. I could have saved a few more dollars and purchased just the 22 AWG wire (and if I knew the melting point of the plastic was 1100 deg F). See page 3 on the PDF for details about temperature by AWG.
Nichrome_Wire_Heating_Element_Design_Basics.pdf (339.71 kb)
I did not purchase a regulator to control the current. Ohms laws shows adjusting the voltage also changes the current (AMPs) for a fixed resistance. Instead I purchased a PSW that had a voltage adjustment resistor. This allowed me to use fewer component with the same result.
24V 15A Dc Universal Regulated Switching Power Supply
Oh yea, the calculator: OHMs LAW Calculator
My final project information:
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22 AWG Nichrome Wire
- 27.5 inches long (2.29 feet @ ~3.0)
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3.9 Ohms overall (includes 18 AWG connection wire resistance)
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5.59 Amps
- 21.8 volts
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Bending temperature 1100 degrees F