Hi
Make sure the grill is well prepared, give it a good rub down with a grey scotch pad getting in all the corners, spray it with a plastisiser which you can by in aerolsol, then you can prime straight onto it once dry, give the primer a light rub down with 5-600 grit paper and the top coat should look good
I would etch prime the handles once they are flatted before applying the primer
It's all about the prep work, as you don't want the paint flaking off
Good luck
