How can I make my slant six exhaust manifold look great?

The VHT "ceramic" in white outlasted a header pipe I had. It goes on then is kinda chalky when you touch it (even dry) until you bake it in a BBQ or just run it for about 30 minutes at idle. Itll set up like pottery glaze and the only way I got it off the pipe was to grind it off. Fun fact: iron taken from a moon ore sample has not rusted on 40+ years and there is a cast iron pillar in Delhi, India that is 1500 years old that has not rusted yet.