Prepping the aluminum armor for paint.
Wash
1:1 distilled water and white vinegar (before and between each sanding grit drying each time with a clean microfiber cloth)
Sanding (I used an orbital 5" sander and discs. I make one pass vertical, one pass horizontal, and then what I call an level'ing pass where I eyeball it to make it all look level and no circular spots)
120 (remove all the nicks and scratches at this stage)
220 (you're just removing the scratches from the 120 as you make finer scratches)
400 (just removing the scratches from the 220 as you make finer scratches)
*Make sure and sand the edges. Edges are where you are most likely to get paint to start peeling. I only sand to 120 on edges because I want the best bite possible and I'm not worried about a super glossy finish on the edges.
Wash
1:1 distilled water and white vinegar
Leave it clean after 400 for your self-etch prime so it gets good bite when you lay down your color. Once you've self-etched primed you're good to leave it as long as you need to. Just follow the directions of your self-etch prime. If you leave it more than 24 hours, some require a light sanding before color.
You want to paint aluminum as quickly as possible. 15-20 minutes max after last sanding pass.
I'll be giving mine another pass tomorrow and then paint. I wanted to get everything to 400 on one day, then go over it again with 400 at the last moment. I'll also re-do the edges with 120. Then I'll be ready to paint.
Here is one side. These were used before I received them, so they had some wear and tear. I'll EDIT later with a pic of the other side after very minimal sanding so you can see how they started (or at least close. I couldn't keep my hands off them for the first few weeks and I did sand some nicks and scratches out prior to this pic).
220
400
The corner is the hardest. I use the orbital,, but I have to come back and hand sand it. It’s not as good, but hopefully the self etch will level it out. It is a self etch filler.