Heat gun for me. Went fancy and bought the digital model with 12 settings or so.

Did read once that someone used the burner on their gas stove-top in a pinch. That I don't suggest.

So that brings us to:

Lighter
Candle
Torch
Alcohol Burner
Heat Gun
Toaster Oven

Yeah ditch the lighter and probably the candle idea. Both don't apply clean heat. They leave soot which keeps the powder from adhering properly.