I could never grasp that myself. A water heater's burner is not much larger than a stove burner, and much smaller than most oven burners, yet that water heater, and furnaces need to be vented
It was explained to me a while ago that stoves are manually operated, water heaters kick on automatically at random times.
Different powder coats do melt at various temps, think the most heat resistant (after initial set) is the thermoset type as it actually changes it's composition during the original bake. The other type (thermoplastic?) essentialy just melts together with no chemical changes in it's makeup, so the melt temp remains the same at all times.
There are a LOT of easily applied ceramic coatings available for home application, satisfaction depends a great deal on prep.
I experimented with lots of different high temp paints over the years (motorcycles primarily) and have been satisfied with a couple.
But the best thing I've found to make any of them last (and it looks good alone) for cycle headers is not intended as a 'paint', it's simply phosphoric acid that's sold in auto stores as a rust stop treatment. Simply clean the metal, lightly scuff it and spray with the rust-stop. Rust will turn to a very hard black oxide that simply will not burn off. Headers here have just over four years on the rust-stop, and still look good.
Picasa Web Albums - ken - bike
Don't mind the seat, it was a quick slap together so I could ride while I built a new one.
If you use a ceramic paint and the part is small enough, bake it in the oven before use, most ceramic paints are VERY soft before they cure, relying on the heat from use to cure it will often result in uncured areas because of uneven heating
I built an oven out of drywall and old stove elements to cure larger parts