Flex Hot Air Welding - Manual

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Flex Membrane International Corp.
2670 Leiscz’s Bridge Road, Suite 400, Leesport, PA 19533 Tel: 610-916-9500 Fax: 610-916-9501
HOT AIR WELDING GUIDELINES
1) Hot Air Welding Equipment
A. Automatic Welding Machine is an electrically powered, self propelled device that utilizes
an electric heating element and forced air to weld the seams in Flex Thermoplastic Single
Ply Membranes.
B. Hand Held Welder is an electrically powered hand held device that utilizes an electric
heating element and forced air to weld the seams in Flex Thermoplastic Single Ply
Membranes.
C. Pressure Roller is a silicon hand roller used for rolling the hot air welded seams.
D. Seam probe is a hand held instrument used for probing the hot air welded seams to insure
the integrity of the welds.
E. Portable generator is required for providing electrical power to the automatic or hand held
welders. A 9500 watt minimum output generator is required to run one automatic and one
held welder.
2) Welding Preparation
A. The surfaces to be welded must be clean and dry. Check the membrane overlaps to
determine whether they have been contaminated with field dirt. If the seam is contaminated,
thoroughly clean the membrane with the recommended cleaner.
B. It is required that all installed membrane seams be hot air welded the same day the
membrane is installed.
3) Automatic Hot Air Welder Operation.
A. Consult the welding machine manufacturer’s recommendations concerning proper
temperature setting and speed control of the equipment. The temperature setting and speed
setting vary with ambient temperature, type of substrate and membrane thickness.
B. A test weld must be performed at the start of each welding session to determine the proper
settings for the machine. As a general guide for welding the Flex PVC and Flex Elvaloy
Membranes the Leister Varimat Automatic Welder suggested starting setting is 1150 ° F at
13’ per minute. The Flex TPO Plus Membrane requires a lower temperature setting 1000°
F at 12’ per minute.
C. Set up the welder and allow it to run for 5 to 10 minutes to warm up.
D. Position the welding unit with the guide handle pointing the same direction the machine
will move along the seam.
E. Lift the overlapping membrane and insert the blower nozzle between the 2 sheets of
membrane. Immediately engage the machine drive to start the machine moving and prevent
over heating or burning the membrane.
F. Guide the machine along the length of the seam keeping the small guide wheel aligned with
edge of the top membrane sheet.
G. When the machine reaches the end of its run, remove the blower nozzle from between the
overlapped membrane and stop the drive mechanism.
H. The portion of the seam at the beginning and end of the run that could not be welded with
the automatic welder must be completed with the hand welder.