Achieving a watertight weld on geomembrane material is all about finding the correct balance of parameters: temperature, speed, and pressure. Leister has produced the below chart as a handy starting point for welding with their geomembrane equipment. Be sure to conduct test welds before commencing.

The main difference between a wedge and a hot air welder is the way in which heat is transferred to the material. With a wedge welder, a solid piece of metal—the wedge—is heated and inserted between the two pieces of material. With a hot air welder, air is heated and then delivered between the two pieces of material via a hot air nozzle. 

Why is using the correct tool for the job important? Results. 

​Using a tool that is undersize for the job will give you unsatisfactory welding results. There are two factors at play: power and weight. 

​Keep an eye out when buying used (and even new!) equipment to make sure the nameplate is intact and hasn’t been altered in any way. We’ve helped a few customers deal with serial numbers cut or scratched out of nameplates. The serial number is the easiest way to confirm age and ownership of a Leister tool. Without a serial number, the manufacturer’s warranty is unusable. You could even be purchasing a stolen piece of equipment. Don’t get caught! Check before you buy. 

​Test welds are an important part of welding thermoplastics whether they’re used for roofing, tarps, pools, tunnels, landfills, or tailings ponds. Welds should be tested first thing in the morning and several times throughout the day to ensure that environmental changes are not compromising the strength of your welds. 

​Plastic extrusion welders can generally be divided into two categories: screw-based extruders and non-screw-based extruders.

Learn our top 5 tips for properly caring for your hot air welding tools and minimizing maintenance. 

​Inside every Leister hot air tool is a heating element composed of a ceramic honeycomb supported resistance wire filament (See below). Electric resistance wire heaters work on the principle that when electrical current passes through a conductor heat is generated, and the amount of heat generated is related to the resistance of the conductor. 

Some resistance wire heaters are able to function without airflow because they have been designed in such a way that they will not reach temperatures above their safe operating limits. Examples include: a toaster, some ovens, wrap heaters, some space heaters, etc.
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However, Leister heaters are designed to operate at very high temperatures—most are designed to heat airflows up to 650°C, and some up to 900°C—and as a result require airflow at all times. To reach these high air temperatures, the heating element must be capable of reaching even higher temperatures. Without adequate airflow, the element will heat up unchecked and will exceed safe limits, leading to the destruction of the element. 

While Laser IR Thermometers are an extremely common tool, they are entirely ineffective for measuring the outlet temperature of an air heater. To understand why, we must first understand how this tool works. Laser IR Thermometers measure the surface temperature of an object by measuring the thermal energy emitted by the target. Knowing the amount of thermal energy discharged and the emissivity of an object’s surface, the object's temperature can be determined by the device.

When measuring a heater’s output air temperature, the largest issue with these tools is that they measure surface temperatures. As the heated air is transparent, the measurement will always be the surface temperature of a nozzle or a component of the heater housing; and frequently it will be an exterior surface. These items will always be cooler than the heated air, often by a significantly larger margin than the user would expect. To accurately measure the output temperature of an air heater you must measure air temperature and laser IR thermometers are incapable of doing so.