Flex Hot Air Welding - Manual (Page 2)

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I. Test welds should be performed at the start of each welding session. Weld 2 sample pieces
of the membrane together. Allow the membrane to cool to ambient temperature. Cut a test
sample across the width of the seam at least 1” wide and longer than the width of the seam.
Pull the welded seam sample apart and examine the width of the delamination from the
reinforcing fabric. The width of the weld should be no less than 1.5” indicating a proper
hot air welded seam.
4. Hand Welder Operation
A. The hand welder is generally utilized for flashing details and field seams less than 10’ in
length.
B. Consult the welding machine manufacturer’s recommendations concerning proper
temperature setting for the equipment. The temperature setting will vary with
ambient temperature, type of substrate and membrane thickness.
C. As a general guide for welding the Flex PVC and Flex Elvaloy Membranes the Leister Triac
Hand Welder suggested starting setting is # 7. The Flex TPO Plus Membrane requires a
lower temperature setting #6.
D. Start the welder and allow it run for a few minutes to warm up.
E. Insert the nozzle of the welder between the 2 sheets of membrane holding the welder in one
hand and the silicon roller in the opposite hand.
F. Slide the welder along the seam while simultaneously applying pressure rolling with hand
welder to the outside edge of the seam.
G. The roller must be placed flat against the membrane to be welded. Do not turn the roller on
edge when welding the membrane.
5. Seam Probing
A. All welded seams must be probed with the seam probe to determine the quality and
integrity of the weld.
B. Allow the hot air welded seam to cool to ambient temperature before beginning the probing
process.
C. Apply pressure and pull the point of the seam probe along the edge of the seam.
D. The tool will not penetrate the edge of a properly welded seam.
E. Repair any voids discovered by cleaning and re-welding the seam.
F. After the repair cools probe the area to confirm the proper weld.
6. Defects and Repairs
A. Voids are repaired by cleaning the two sections of membrane and inserting the nozzle of the
hand welder into the void. Apply pressure with the silicon roller and roll the top surface
towards the outer edge to cause the membrane to fuse together.
B. Wrinkles in the seam, burn marks or overheated areas, and any area where adhesive
contaminated the seam must have a patch installed over the defective area.
C. When installing a patch the area to receive the patch must be thoroughly cleaned.
D. The patch is to be made from the reinforced plain backed membrane.
E. The patch should be sized to extend past all edges of the defective area a minimum of 2”
with all corners rounded.
F. The patch is hot air welded to the existing membrane.