PREP: Since the existing paint was so worn and thin anyway, I went ahead and stripped the trailer down to bare aluminum using an extra fine wire brush on my drill (I experimented with this first and the brush left less scratch marks than 100 grit sandpaper, and it buffed back to smooth with rubbing compound). I worked in sections and it took about two full 8-hour days to get her clean. Afterwards we washed the trailer with soap and water, then wiped it down with denatured alcohol.

STRIPES: Next we buffed where the 1" exposed aluminum stripes will be with a 4" buffing disk on the drill and No. 7 Rubbing compound (both from Ace). The rubbing compound worked really well and got the aluminum to a mirror shine in most places (we will go back after all is said-and-done with Mother's polish and get the stripes as shiny as we can). There were a few areas on the high-side of the curved aluminum ribs where the aluminum was just plain worn out/baked, but it still shined up, just not as much. The compound left some black residue 1/4-1/2" above and below the stripes but I went back and cleaned it off with mineral spirits and another wipe-down with alcohol. Either the residue or using mineral spirits to clean it apparently presented a problem with the primer, which I'll explain later. We masked off the stripes with the green "3-day" painter's tape.

PRIMER: I struggled with this a little...I know to use a self-etching primer on aluminum, but Rustoleum makes a water based "aluminum and galvanized metal" primer that states you can use oil-based enamel over it. You just need to wait at least 16 hours before painting with oil-based paint. I researched this as best I could, and the always helpful paint kid at the big-box hardware store swore that it works, too. And at 8 buck a quart for the Rustoleum versus $109 a gallon for the self-etching primer, my cheap instincts kicked in and I gave it a try. I used 3 quarts total thinned 10% for two coats. It went on super-smooth and with no problems whatsoever. I lightly sanded between coats and prior to painting. We also wiped the trailer down again with denatured alcohol before painting.

PAINTING: We decided to paint the blue trim first, since it was smaller in area and I felt we could plastic it off afterwards a lot easier than the rest of the trailer. We used a high-gloss rustoleum oil-based enamel tinted to the blue we wanted. We sprayed the trim, sanded/alcohol/waited, applied the second coat, sanded/alcohol/waited, and finished the third coat. The next day we put plastic over the blue trim, securing the plastic with the cheaper white masking tape, making sure to leave about 1/8"-1/4" of green tape exposed. As I was wiping down the trailer with alcohol I noticed some very small blistering right below the stripes/masking tape. I scratched it with my fingernail and it peeled right off...to about 1/4"-1/2" below the stripe. I mean it literally pealed like a kid's sticker book collection...all along the stripes, but no further up or down than where the rubbing compound residue was. I feared that the latex primer was a mistake, but as I peeled and then scraped it really hard with a paint scraper, the scraper literally stopped right where the black residue from the rubbing compound used to be. As I got into it, I realized that the primer directly above and below the stripes had not adhered to the aluminum AT ALL. Everywhere else the paint and primer is as hard as a rock and will not scratch off, even with sandpaper or a metal scraper. So I figure I didn't clean the rubbing compound residue enough, or the mineral spirits I used to clean the residue blocked the latex primer from bonding with the aluminum (or both)? Any ideas on this?

SO, we peeled and scraped both sides of the tape, sanded the good primer down at the edges so there are no paint lines, wiped down the trailer with w/alcohol and sprayed the main field color (an almond white industrial automotive paint with an accelerator/hardener for extra gloss, and thinned with naphtha for spraying), three coats. It went on perfectly and with no issues, and It's not peeling or blistering now.

We've re-covered the white part in plastic and I just finished peeling/scraping/sanding the blue trim and plan to re-prime tomorrow and re-paint the trim on Tuesday. Although this setback cost us about five days, all is not lost, though, since we didn't really love the blue that we originally chose and even though the blue enamel was a high gloss, we just didn't get the gloss that an auto paint would give us. So we are going with a lighter blue and I'll be adding a hardener/accelerator, which adds gloss.

As far as the Rustoleum aluminum primer, it seems to have worked really well everywhere but at the stripes. I guess only time will tell though.

Another lesson learned and one more thing that will make us appreciate our project...and an excuse to have a few extra beers along the way.