Clean clean clean in my opinion. Not hard to do and doesn’t take up too much time to do it right. You can see how I did my exhaust pipes which most people will never see. I used a 40 grit disk on a grinder mainly because it was fast and easy. 80 grit is what I originally planned but didn’t have a disc on hand. Used a respirator as well. Aluminized coating is bad on the lungs. I wasn’t too worried about sanding scratches and I wanted to see how well this product filled the scratches. I used a quality wax and grease remover and let it gas off for an hour. Similar to when I paint cars.
Needless to say I’m very impressed overall. This stuff is VERY high build. As said before, one coat is all you need. I look forward to trying out their clear-coats on buffed aluminum. Apparently they have one that only requires Dawn dish soap for prep after polishing.
One more thing. I’ll order a 4oz tester for when I clear coat my trim pieces. I can’t see paying 3-4K to have all my trim, grills and sail panel brite dipped. I think this is a great alternative.
You should look online and see how they are painting rifles, handguns and knives. Impressive. If it can handle explosions from a high powered rifle it’s gotta be tough