A heat gun's temperature selector regulates resistive element output in watts. It does not measure, control, or indicate the temperature of the surface being stripped. Air temperature decays with distance, spreads with nozzle geometry, and interacts unpredictably with substrate color, texture, and ambient airflow.
The IR thermometer in our kits detects thermal radiation in the 8-14 µm band, converting it to surface temperature with ±1.5°C accuracy at typical working distances. It reads emissivity-adjusted surface temperature, not air temperature. This is what matters: the temperature the wood fibers, metal oxide layer, or plastic polymer actually experiences.
Hold the thermometer 15-30 cm from the surface at 90 degrees. Measure immediately after the heat gun passes, within 2 seconds, before conduction and convection dissipate the heat. Record peak readings across several passes to establish your working envelope for that substrate and ambient condition.
Dark, oxidized metal reads higher than shiny bare steel at the same actual temperature due to emissivity differences. Rough wood reads closer to true temperature than glossy varnish. The thermometer's default 0.95 emissivity setting works for most restoration substrates. For polished aluminum panels, expect a 10-15°C reading offset; trust your pass timing and physical response over the absolute number.