View Single Post
  #13   Report Post  
Posted to
N_Cook N_Cook is offline
external usenet poster
Posts: 5,247
Default Nichrome Wire Temperature for Cutting Sofa Cushion Foam?

On 27/01/2018 18:12, Sjouke Burry wrote:
On 27-1-2018 19:03, N_Cook wrote:
On 26/01/2018 18:34, wrote:

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.
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.

You reminded me, I had to add a spring in line with the wire, as the
wire would break when it cooled down.