:welcome:
Sealing is basically dipping it in boiling water with a coule of passivating chemicals.
Before powder coating it needs to be activated.
Most powder coaters will do it as a matter of course.
A sealed surface can be painted using the proper paints starting with a bare metal primer.
Do not use the single "can be painted over bare metal" paints as they will not adhere properly and in time will fall off in blotches.
POR 15 makes the best alloy paints that actually work. they are expensive and only buy a smal can because once opened will go off so can not be stored for any length of time.
Brushes can not be cleaned so buy a pack of their disposable brushs as well.
It is a complicated process of cleaning , activating, undercoating & top coating but once done properly bullets will in fact bounce off ( glancing shot ).
After that there ar a lot of aero paints , designed for aeroplanes you get from places like Aircraft Spruce. Again bullet proof finishes but because it flys it will cost more.