Heat fusion (sometimes called heat welding, butt welding or simply fusion) is a welding process used to join two different pieces of a thermoplastic. This process involves heating both pieces simultaneously and pressing them together. The two pieces then cool together and form a permanent bond. When done properly, the two pieces become indistinguishable from each other. Dissimilar plastics can result in improper bonding.

The Model FW-5A is equipped with a precision air regulator which enables the process controller output to the heatgun heater element control circuit only if an adequate air source is connected. The process controller is equipped with a digital display which shows the real time temperature of the heated air flowing out from the heatgun element.


The desired air temperature can be programmed into the controller and can be changed as welding conditions vary. The control box is equipped with two separate switches, where the HEAT switch will not work unless the MAIN POWER switch is enabled. Note that the MAIN POWER switch is also an overcurrent protection device.