I'm making a hot wire cutter for polystyrene foam. Thw cutting wire will be
Nichrome.

Does anyonw know of a formula that will give me the means to calculate
possible voltage and amperage combinations to put through it (so I don't
melt the wire)?

I know that a 9v 1A setup will work, but I would like to know what others
could be used.

The point at which the wire will melt is called fusing current. This page
provides fusing current for different copper wire sizes:
http://www.interfacebus.com/Referenc...AWG_Sizes.html

The heat generated by the wire is; current (squared) x resistance. The
resistance per 1000 feet is also provided on the page link.

This sounds dangerous

"suryah" wrote in message
...
I'm making a hot wire cutter for polystyrene foam. Thw cutting wire will
be
Nichrome.

Does anyonw know of a formula that will give me the means to calculate
possible voltage and amperage combinations to put through it (so I don't
melt the wire)?

I know that a 9v 1A setup will work, but I would like to know what others
could be used.

On Mon, 21 Feb 2005 07:01:01 +0000, suryah wrote:

I'm making a hot wire cutter for polystyrene foam. Thw cutting wire will be
Nichrome.

Does anyonw know of a formula that will give me the means to calculate
possible voltage and amperage combinations to put through it (so I don't
melt the wire)?

I know that a 9v 1A setup will work, but I would like to know what others
could be used.

For styrofoam, just get a decent bread knife. An X-acto, or even a razor
blade, is good for small pieces.

Don't try to cut styrofoam with a hot wire. If it gets anywhere near
hot enough to "cut" the foam, it melts it and you get a globby mess.

Or, dip the wire in glue and drag it through sand, and make a little saw
out of it.

Good Luck!
Rich

Thanks for the link. It's not dangerous. I know that the stated setup works.
It's just that other PSU's are more easily obtainable, and I wondered which
would work and which would not.

Hot wire cutters are often used in trade and by hobbyists - particularly
model railroaders. Woodland Scenics sells them - but I'm not going to pay
their prices!