View Full Version : Need Help! power supply for 2mm hot wire

08-11-2011, 03:58 AM
i Just stuck with 2mm gauge nicrome wire, i want to make some turning table arch shaper. but i dont know how to heat my 2mm nicrome wire.
anyone here can help me?

I have a 24 volt 20 Ampere power supply, i use it with 1mm nicrome wire, and it can produce a good heat for the wire.

than i try it with 2mm nic wire. the wire just warm.
what is the problem.

do i have to make a new power supply?

or i can modified my 24volt 20 amp power supply, that can heat up my 2mm nicrom wire?

is there anyone have try this? :confused:Help me please

08-12-2011, 10:38 AM

Quick answer to the power supply is yes you need an supply with more voltage.
As wire length or Diameter increase more voltage is needed to push enough amps to heat the wire to the cutting temperature.

I suggest to make or buy an adjustable supply of minimum of 50 or 60 volts. Commercial supplies of this size are very expensive.

I use an home made supply of aproximate 8 amps 50 volts, controled by a light dimmer, to control the voltage to the wire. My bow is 54 in. long with .014" Rene wire and it takes about 28 volts maintain 1.2 to 1.5 amps cutting temp.


08-12-2011, 12:13 PM
I used an AC arc welder with adjustable choke.
If it puts out too much power, put a 1 bar radiator in series with the mains input side.

08-15-2011, 04:06 AM
Thanks for the answer


Sounds so dangerous..hahaha


you mean that i just have to increase the voltage not the current?

08-15-2011, 04:11 AM
If it is wired in through a junction box, with a supply plug, and an outlet plug and even a switch, ensuring the earth wires are all connected, just don't put the radiator where it will set fire to something.(flame2)
For years we choose not to put our fingers in radiators for obvious reasons.
You can do anything the wrong way, if you choose.
At least some questions have been asked.:rolleyes:

The output of the welder is isolated from the mains. so where is the problem? Well the hot wire could be dangerous.
You will get 40vAC on the high current terminal, or 80vAC on the 'special' terminal.

08-15-2011, 06:22 PM


you mean that i just have to increase the voltage not the current?

20 amps. is enough for the wire. You need the voltage to push the amps. You have double the wire size so you need to double the voltage or more to be able to push enough amps. to bring the wire to cutting temp.

You will find that different foams take different heats on the wire. At present I only use the white beaded foam for making wing cores for my RC. planes and it only takes between 1.2 to 1.5 amps. to get a good smooth surface.

I use DC voltage instead of AC for I intend to use a 4 axis cnc machine in the future and use GMFC software with controler with auto heat control. http://gm.cnc.free.fr/en/index.html
I have everything except I havn't built the machine yet.


08-15-2011, 07:20 PM

Here are some pics. of my supply. All load test are using 54" bow with Rene Wire.

Hope this helps you.

09-05-2011, 11:04 AM

I've had good results with a light dimmer switch connected to the input of a car 12V battery charger. Most have an ammeter on them and I adjust it to between 1.5 to 2.0 amps. You can see my results at RC SuperVC10 build (http://www.rckeith.co.uk/vc10/vc10build.html) about half way down the page. Wasn't using CNC then but I'm in the process of building one. I cut both white foam and XPS. I foudn XPS need about 2.0 amps and white foam was a bit less.

hope that helps