The BAK 40mm wide slot nozzle (BAK article 5107132) push-fits onto the ø32mm outlet of a hot air hand welder. The 40mm x 2mm outlet is the standard seam width for overlap welding TPO and PVC single-ply roofing membranes, and it is the nozzle size BAK ships with RiOn welder kits.
Fits these welding guns
- BAK RiOn Hot Air Welding Gun 230V
- BAK RiOn Digital Heat Gun 230V
- Leister Triac AT Heat Gun
- Leister Triac ST Heat Gun
The 32 mm push-fit outlet is the common size on trade hot air hand welders, and other brands use it too. Check the outlet on your gun if it is not one of the models above.
Where the 40mm works
- Standard overlap seams on TPO and PVC single-ply roofing membranes.
- Long straight runs along field seams, with a silicone pressure roller following the weld.
- Wider overlaps on tarpaulins, liners and geomembrane sheet.
Welding technique: heat the overlap with the nozzle, then press the softened seam with a silicone pressure roller as it cools.
40mm or 20mm?
The BAK Wide Slot Nozzle 20mm (article 5107123) holds a narrow line for flashings, corners, patches and small repairs. Keep both on the kit when a roof has field seams plus detail work.
Good to know
- Nozzle only. A hot air hand welder is required and is sold separately.
- For hot air welding of thermoplastics. It does not suit propane torch-on bitumen work.
- BAK makes perforated and bent 40mm variants under different article numbers. Match the article number 5107132 to your gun manual when you order.
- Weld inside the membrane manufacturer's temperature window and test a weld before production work.