Hot Gas Welding of Thermoplastics

Hot gas welding is analogous to oxy-fuel welding for metals but operates at much lower temperatures and uses hot gas instead of an open flame. The process requires a handheld or automated heat gun, pressure rollers, and a filler rod made of the same or a very similar plastic as the workpiece to ensure material compatibility. The temperature of the hot gas is critical and must be carefully controlled based on the specific thermoplastic being welded, typically ranging from 200°C to 300°C (400-575°F). Proper technique involves maintaining a consistent angle and distance for the heat gun and applying steady pressure to the filler rod to force it into the joint. Surface preparation, such as cleaning and beveling the edges of the joint, is essential for achieving a strong weld. The technique is versatile and portable, making it suitable for both in-shop fabrication and on-site repairs. It is commonly used for materials like polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), and acrylonitrile butadiene styrene (ABS).