DIYbanter - View Single Post - Nichrome Wire Temperature for Cutting Sofa Cushion Foam?

Sjouke Burry[_2_]

On 27-1-2018 19:03, N_Cook wrote:
On 26/01/2018 18:34, wrote:
Hi,

I recently bought 18 gauge Nichrome wire for the purpose of cutting a
Sofa cushion foam in half (split the cushion foam, in effect make the
cushion half as thick). Length of wire I will heat is 3 feet (cushion is
almost 2 feet wide)

I have what I need to adjust the current from 1 to 12 amps. Also,
I have a chart for amps relating to temperature. Example: Apx. 6.5 amps for
600 degrees F. for 18 gauge Nichrome wire.

The only information I was unable to find was the recommended
temperature for cutting foam with this type of wire.

Thank You in advance, John

If you want to keep the wire taught , for a good straight cut, you have
to compensate the expansion of the wire.
I used a large hacksaw frame, adding an insulating ceramic bead at the
fixed and and using the screw adjuster for blade tension, to tension the
resistance wire. I think I just unwound a high power wire-wound resitor,
value and supply requirement unremembered, but I probably used a variac
supplying a step down high current transformer

We used a small wheel on one end of the wire, and had a weight
attached to the wire. Produced a nice constant tension.
A variac transformer to supply controllable heat.
The setup was also used to bend plastic sheet.