Pendulum Welding

9/19/2014

Good plastic welding practice requires three elements; proper temperature setting, consistent welding speed and even pressure on the welding rod. Using these three elements correctly will result in a slightly foam wash like appearance on the both edges of the weld which should result in good weld penetration and strength. The wash should not be brown or black as this indicates overheating

Starting the Weld: Hold the welding rod at the correct angle - 45 degrees for PE, PP for PVC 90 degrees to the base material.

Continuing the Weld: Once the weld has been started the hot air should be fanned from the rod to the base material with approx. two full oscillations per second. Wherever possible the weld should be completed in one continuous run along the groove.

Ending the Weld: Stop all forward motion and direct a quick application of heat directly at the intersection of the rod and the base material. Remove heat maintain downward pressure on the rod for several seconds.

Corner Welds: Always start a weld in a corner, do not weld to a corner. Trim welding rods to a pencil point to allow for staking of start of welds in the corner. Layer each pencil or arrow rod’s end for each corner groove.

Welding seam preparation

Welding area & weld rod must be:

dry, clean, free of oil & grease
free of notches
free of oxidation (to achieve this the joining area is scraped clean just before welding

Note on compressed air usage:

If using compressed air with your hot air tool, ensure that there is a pressure reducer and an oil and water filter before turning the air on

Welding parameters

Material	Welding force (3mm rod)	Welding force (4mm rod)	Hot air temp.	Air flow
PE-HD	10 - 16 N	25 - 35 N	300 - 320°C	40 - 50 l/min
PP	10 - 16 N	25 - 35 N	305 - 315°C	40 - 50 l/min
PVC-U	8 - 12 N	15 - 25 N	330 - 350°C	40 - 50 l/min
PVC-C	15 - 20 N	20 - 25 N	340 - 360°C	40 - 50 l/min
PVC-P	4 - 8 N	7 - 12 N	300 - 370°C	40 - 50 l/min
PMMA	12 - 16 N	20 - 30 N	320 - 370°C	40 - 60 l/min
PVDF	12 - 17 N	25 - 35 N	365 - 385°C	45 - 55 l/min