Heat sealing irons aren’t very accurate when it comes to their temperature settings, and there’s significant variation among them (even between irons of the same model). When heat sealing the DIY Packraft fabrics, you’ll want to set your iron so the surface temperature is approximately 200° C, or 400° F – but don’t trust the numbers on the dial. (You also can’t trust infrared thermometers on some irons because their surfaces are too small or too reflective.)
My Coverite Black Baron iron works best with the dial set close to its highest temperature, but not quite all the way up. When I use a Coverite Pocket Thermometer (pictured below) to check the iron’s surface temperature, it reads about 196° Celsius, or 388° Fahrenheit. Of course, I’m not sure how accurate the pocket thermometer is either, or if each one is calibrated the same, so your results may vary.
The best way to set the iron’s temperature is by trial and error, as described on the Proper Heat Sealing Technique page.
The inexpensive Coverite Pocket Thermometer
The Pocket Thermometer sits on the iron’s surface.
The Pocket Thermometer is a simple metal coil that expands when heated.