Hot glue falls into the same category of duct tape and zip ties as a versatile material for fixing anything that needs to be stuck together. [Ed]‘s Bosch glue gun served him well, but after a couple of years the temperature regulation stopped working. Rather than buying a new one, he decided to rip it apart.
With the old temperature regulation circuit cooked, [Ed] looked around for something better on eBay. He came across a cheap PID temperature controller, and the Frankengluegun was born.
A thermocouple, affixed with some kapton tape and thermal paste, was used to measure the temperature of the barrel. Power for the glue gun was routed through the PID controller, which uses PWM to accurately controller the temperature. All the wiring could even be routed through the original cord grips for a clean build.
Quality glue guns with accurate temperature control are quite pricey. This solution can be added on to a glue gun for less than $30, and the final product looks just as good.