For anyone interested in spraying or rolling their hail damaged or dented aluminum roof, I highly recommend U-Pol Raptor tintable bed liner kits. Each kit comes with four bottles of bed liner (that screw directly into a shutz gun), a tin of liquid hardener and instructions. The base paint (for tinting) is extra but a required step as the bedliner won't harden properly without it. While spraying is definitely the way to go with this stuff, I wouldn't hesitate to roll it on either. It's super easy to work with and dead simple to get consistent results. Just know that the overspray will get EVERYWHERE, so cover your garage floor and anything else you'd rather not have sprayed. Being that the roof had been through several serious hail storms and what appeared to be the results of a few canoe trips, I also used a gallon of generic "Gold" body filler. Note that regular body filler isn't advised as it lacks the ability to bond well with bare aluminum. I removed the plastic corners and top trim then used a wire wheel to rough up the surface prior to wiping it down with acetone. I then applied a skim coat of body filler which was then cross sanded using a sanding block and 40 grit automotive sandpaper to smooth things out quickly. Basically, I spread out a skim coat of body filler, then sanded and reapplied where required. After the second layer of body filler had hardened, I sanded again and wiped it with final wipe. Then I shot the bare metal with self etching primer and regular automotive primer for everything else. I then cross sanded the whole surface with 80 grit paper, an orbital detail sander and my trusty sanding block. This stuff likes a rough surface to adhere to, so there's no need to make sure everything is perfectly smooth. Just so long as the surface is level, you're pretty much good to go. The primer really shows where the imperfections are and makes it easier to get them sanded down or filled and sanded prior to the paint being applied. That said, the bed liner covers a multitude of sins, so small imperfections, scratches and pinholes caused by air bubbles won't even be noticeable. For this project, I used one can of self-etching metal primer and three cans of regular automotive primer and sprayed the entire surface of the roof prior to spraying the bed liner. Once I'd levelled out the roof and filled the dents, I gave it another wipedown with "final wipe" and set up to spray. I used two of the tintable kits sprayed at 60 psi through a "Shutz" gun. This allowed me to spray two coats of bed liner on both the top and sides. The autobody paint supplier I bought the kits from poured eight 75-80ml bottles of white base paint to make mixing consistently a cinch. BTW, the paint vapors from this stuff will rock your world but they're nothing a $20 mask can't take care of. The manufacturer says each kit covers 100 square feet, so each coat will take a full kit. After having done this, I'd highly recommend THREE coats, (or three kits) just to ensure consistent coverage and to allow for touchups. Spraying one coat will take about an hour and that's the potable time for each bottle of Raptor before it starts to harden in the bottle. When you're done spraying, be sure to clean the shutz gun with gun wash or acetone after each coat as it takes about an hour to "flash" before you can give it another coat. You can remove tape 15 minutes after you've sprayed your 2nd (final) coat. I finished spraying the second coat at 10:30 am, removed the tape/paper and let it sit. While we loaded it and the truck for the weekend. I started putting the butyl tape, roof trim and plastic corners back on at 6:00 and had it hooked up and ready to go at 8:30pm. We didn't slide the bag awning into the rail until we arrived at the CG and thankfully, we didn't see any rain until our trip home, so things had more than enough time to cure over the weekend. The manufacturer says you can "deliver" after eight hours and that it's fully cured in 5-7 days. I can tell you personally, that after 2 days, it's pretty tough. I like this stuff and I'd do it again in a heartbeat. While two coats is adequate, three would be the way to go.