CSLB C-39 Roofing ContractorLow-Slope RoofingEasy
A technician is using a hand-held hot-air welder to seam TPO membrane sheets. What nozzle temperature range is typically used as a starting point before fine-tuning for ambient temperature and travel speed?
- A900-1100°F
- B300-400°F
- C1300-1400°F
- D500-600°F
Show answer & explanationAnswer & explanation
Correct answer: A. 900-1100°F
Hand-held hot-air welders for TPO typically start in the 900-1100°F range, with adjustments made based on ambient temperature, humidity, and travel speed to achieve a proper weld without scorching the membrane.
Why the other options are wrong
- B. This is far too low to melt and fuse the TPO surfaces.
- C. This is excessively high and would scorch or burn through the membrane.
- D. Still too low for effective TPO seam welding.
TPO Hot-Air Welding Temperature
Hot-air welding fuses TPO seams by melting the membrane surfaces so they bond together under roller pressure.
- Typical starting range is 900-1100°F
- Temperature must be adjusted for ambient conditions
- Weld quality is verified with a seam probe test
Memory trick: Nine hundred to eleven hundred, hot enough to bond it.