Attached are examples of the heating element and thermistor I have and need to use.
That cartridge heating element looks like its designed for insertion into a metal block. Blowing air over the isolated element is not optimal. I would drill a hole in an led star heat sink (or some other high surface area piece) for placement the element.
I would like to know what I need additionally to do the temperature controlling of the heating element.
You will need a way to switch the 12v. Logic level MOSFET or relay.