www.TK560.com

[vacunoob]

I've got some left over Nichrome coil and I wanted to make a custom hot knife. I've tried to figure out the mininum amount of wire I would need to use for 120V / 15 or 20 amp but I'm stumped. The specs. on the nichrome is catalog # L22-10C, AWG 22, 360 ohms, & outside diameter .3".

I tested a stretched 6" piece and it popped.

I=V/R ?

Can anyone give me some insight?
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Failure is only possible if you set a time limit.

Flickr: Vacuum Former Pics
Product I vacuum form- Laser Speed Grids

[clonesix]

Welcome to the forum. I am glad you didn't hurt yourself with your first try.

Look here for a hot wire explanation:
http://www.hhhh.org/~joeboy/resources/hotwire_foam_cutter/hotwire_foam_cutter.html


http://www.heatersplus.com/nichrome.htm

[vacunoob]

Thanks for the link and the welcoming. I love this forum!

I hope to learn a little more about the math and science behind determining the correct length of nichrome based on amps and volts.

Could a simple AC adapter work as a power supply?
_________________
Failure is only possible if you set a time limit.

Flickr: Vacuum Former Pics
Product I vacuum form- Laser Speed Grids

[jdougn]

If the hot knife is going to be used to cut ABS there is a concern about the ABS resealing behind the knife. I use a jig saw on slow speed and if the ABS is too hot it will reseal behind the blade.
YMMV, Doug
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DougN - Just in case you're wondering, I got my "rating" legitimately... by posting aimless drivel, useless advice, and pointless questions.

[jegner]

I've seen hot knifes running off a couple of 'D' cell batteries, and I've seen them connected to a model train speed regulator, or even a battery charger! Regulating the power going to the nichrome wire is the trick.

http://www.youtube.com/watch?v=P9IMIoJw61M