I did a little better taking photos this time. You can see the HS in the paint booth ready to be painted. Then the green primer is the wash or etch primer. It is just one thin coat. The wash primer makes a mechanical bond with the aluminuum and sets up to make chemical bonds with the primer and paint. Chemical bonds are far stronger than mechanical bonds. So the wash primer is put on thin and must be overcoated within 8 hours so its chemcial surface doesn't oxidize.