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

On 1/26/2018 1:34 PM, 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





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

In article ,
says...

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

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.

On 1/26/18 3:58 PM, Mike Coon wrote:
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.

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
WA6FWi
http:foxsmercantile.com

On 1/26/2018 10:34 AM, 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
That's power control, not temperature control.
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.

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

On 01/26/2018 05:56 PM, MOP CAP wrote:
Maybe a better solution? I have used an electric carving knife for
cutting non ridged foam.

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

--
Cheers, Bev
"If your mechanic claims that he stands behind his brake jobs, keep
looking. You want to find one willing to stand in front of them."

-- B. Ward

On Friday, 26 January 2018 21:58:51 UTC, Mike Coon wrote:

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.

no he doesn't


NT

On Friday, 26 January 2018 22:25:50 UTC, mike wrote:
On 1/26/2018 10:34 AM, 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)

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.

more nonsense.

On Fri, 26 Jan 2018 19:18:51 -0800, The Real Bev wrote:
On 01/26/2018 05:56 PM, MOP CAP wrote:
Maybe a better solution? I have used an electric carving knife for
cutting non ridged foam.

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

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

Jonesy

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

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.

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:
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.

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

On 1/27/2018 8:19 AM, Allodoxaphobia wrote:
On Fri, 26 Jan 2018 19:18:51 -0800, The Real Bev wrote:
On 01/26/2018 05:56 PM, MOP CAP wrote:
Maybe a better solution? I have used an electric carving knife for
cutting non ridged foam.

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

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

Jonesy

After googling IJFW and going to deep I found,
IJFW » Impressionable Joyous Fearless Wise

On 1/26/2018 4:58 PM, Mike Coon wrote:
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 ...

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

Once upon a time on usenet amdx wrote:
On 1/27/2018 8:19 AM, Allodoxaphobia wrote:
On Fri, 26 Jan 2018 19:18:51 -0800, The Real Bev wrote:
On 01/26/2018 05:56 PM, MOP CAP wrote:
Maybe a better solution? I have used an electric carving knife for
cutting non ridged foam.

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

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

Jonesy

After googling IJFW and going to deep I found,
IJFW » Impressionable Joyous Fearless Wise

It Just ****ing Works?

I've never seen the acronym before but I find most acronyms can be
deciphered using context and imagination.
--
Shaun.

"Humans will have advanced a long, long way when religious belief has a cozy
little classification in the DSM*."
David Melville (in r.a.s.f1)
(*Diagnostic and Statistical Manual of Mental Disorders)