Dimmer

If air is moving or a fan is blown over it, the temperature will be reduced
If the wire is coiled, the smaller the coils and closer together they are, the hotter it will get and can get as much as twice as hot.
If the wire is in contact with another material or sandwiched between materials or wrapped around something, the temperature will be different.
- If the material does not conduct heat well such as glass, ceramic, or other insulations the temperature wire temperature will be hotter and may continue to increase in temperature until it melts at some spot and breaks.
- If it is in contact with metal, first of all it will short out so that the exposed part of the wire if any will get much hotter and probably melt in a spot and break. If the material is insulated with a very thin insulating material and then metal, it will be cooler because heat will be drawn away faster.

When cutting foam, the wire will initially be close to the temperature indicated in the calculator but as soon as it starts cutting foam, it will cool down to a lower temperature and then stabilize there. So it will cut faster at the beginning and then slow down. A sawing action would cut faster because the hotter wire in the air would be constantly being moved down into the foam and the cooler part of the wire will exit the foam and heat up again.

I recommend 800F as a minimum temperature for a reasonable rate to cut foam and a maximum of about 1100F. 600F will work but will be slow.

To bend plastic up to 1/8", you need to have at least 20 gauge nichrome at least at 1200F when in a 3/4X1/2 aluminum channel to reflect the heat up to the plastic.

The temperatures are plus or minus 5%.

You cannot measure the temperature of a wire directly with anything.

An infrared heat gun requires a larger area than the wire so will read the background temperature as well as the wire temperature and so will ALWAYS read LOW.
An attached thermal device such as a thermocouple will change the heat transfer characteristics at the spot and so will not give an accurate temperature. For thermocouples to work, the item attached to must have a large mass in relation to the mass of the thermocouple. With a wire, there will be more surface area and so read cooler unless there is a significant amount of material used to attach it such as potting material or adhesive in which case it would insulate it and the temperature would read high. Either way it will not be accurate.
The only way to determine the temperature is to calculate it based on the current flowing through it and the gauge and for a specific configuration as described in the first bullet above.

To select one of the two calculators below, click on the picture. Note the pictures are NOT the working calculators.

Two calculators are available. The first one shown (left) is the latest and is done in html which means that it will work on all devices--desktops, laptops, tablets, and cell phones. On mobile devices you will need to manually expand it to the size of your screen. For the resistance wire gauge, you need an integer. A coming update currently in work will allow decimal gauges and lengths and ohms per length also in metric values and hopefully eventually will resize to full screen automatically for mobile devices. You can either input the desired temperature and calculate volts or input volts and calculate temperature. You can also pick the alloy type: Nichrome 60, Nichrome 80, Rene or Kanthal. You can also if desired enter the gauge and length of wire going between the supply and the resistance wire to see how much voltage and temperature drop it will cause.

The second one shown is the original one created as a flash movie which was popular a few years ago but is currently being phased out. Flash is not supported on any mobile device but with some effort might be possible with certain browsers and plug-ins. It was built with sliders because most people have a hard time understanding how the wire gauge, wire length, voltage, and temperature interact. You could move the sliders and see how larger gauge wire required less volts and more amps for the same temperature, how a longer wire decreased the temperature, how the temperature is only dependent on the amps for a given gauge wire and so on.

By default flash is now disabled and you have to manually enable it and depending on the browser, sometime in 2020 it will no longer be able to be used on any browser. For now to allow flash on chrome click here, for Firefox click here, for internet explorer click here, for safari click here, for opera click here.

The top of the screen with the calculator gives additional operation instructions and other information. Note the lower left corner has ranges that can be changed so you can use a wider range of values with the sliders