How Hot is Hot Glue?

After sustaining a few hot glue burns during the construction of the Disneyland costume, I marveled at how the burns never hurt for very long. The glue temperature was high enough to be painful, but not so high that the burns were serious.

How hot is hot glue? My first measurements came from a non-contact temperature-sensing gun. Unfortunately, the thermo gun wasn't reading the temperature of the hot glue. It must have had something to do with the transparency of the glue.

I switched methods, measuring the glue temp with a digital cooking thermometer.

The behavior of the glue was unusual.

A small pile of glue was only registering as warm, but as I squeezed more and more molten glue out of the gun, the reading kept going up. 150, 160, 170….. 180. Finally it peaked at 190° F.

This was a cheap hot glue gun, the blue one in the photos.

My favorite is this Arrow glue gun. The test indicates that glue from it emerges at only about 175°F.

It should be noted also that the tip of a hot glue gun isn't likely to be as hot as the glue itself. The metal tip reminds me of a soldering iron, which is designed to be hottest at the tip, but this is not true of a glue gun.