Nichrome Wire Temperature for Cutting Sofa Cushion Foam?

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

Reply to
jaugustine
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Why not just keep cranking until you get the desired results?

Reply to
Tom Biasi

Not a very helpful contribution, sadly, but that chart relates to wire in free air (presumably). As soon as you put it in contact with the foam it will cool down and not cut. You really need something that is thermostatically maintained and more like a knife with some thermal inertia.

And the temperature you need depends on the foam composition, which you have not told us!

Mike.

Reply to
Mike Coon

Or, you can do like every other hot wire cutter. It's too hot in free air, but cools down to just right once it makes contact with the foam.

--
"I am a river to my people." 
Jeff-1.0 
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Reply to
Fox's Mercantile

You really don't have options other than try it and crank up the power until it works at the chosen, fixed, constant feed rate.

You're gonna have to juggle a lot of variables to make this work. Second most important issue will be the jig that keeps the wire and the cushion from flopping around while you're trying to cut it.

Most important thing is ventilation. Some of that stuff is extremely toxic.

Reply to
mike

Maybe a better solution? I have used an electric carving knife for cutting non ridged foam. CP

Reply to
MOP CAP

My upholstering friend uses an electric knife to carve foam. When she was tailoring, the insides of her garments looked like outsides!

--
Cheers, Bev 
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Reply to
The Real Bev

no he doesn't

NT

Reply to
tabbypurr

more nonsense.

Reply to
tabbypurr

+1 I've done it a few times and IJFW.

Jonesy

Reply to
Allodoxaphobia

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

Reply to
N_Cook

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.

Reply to
Sjouke Burry

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

Reply to
N_Cook

After googling IJFW and going to deep I found,

Reply to
amdx

Exactly. You can use the wire itself as the sensor - its resistance varies with its temperature. So you just need a little circuit to maintain a constant wire resistance. Adjustable, of course to get the temperature that you need. I'm not enough of a circuit designer to tell you how to do it, but I'm sure that someone over at S.E.D. would enjoy the challenge.

Bob

Reply to
Bob Engelhardt

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