The sealer of choice is Permacoat™ 62. This product is specifically designed for aluminum and delivers excellent results. It requires proper preparation of the surface before it is sprayed on. This method gives the satin finish that appears similar to a wet surface. It is a thin and delicate coating. If you scrub aggressively or use a squeegee to dry, it can remove the finish. The finish requires little maintenance. Washing once or twice a year unless you get muddy is all that is required. If the Permacoat 62 does come off prematurely you can successfully patch that area with a rag dipped into the product. Expect the Permacoat 62 to last 4 - 6 years and that you will pay $600 each time if you have it done professionally. I highly recommend professional application. Surface preparation is the key to success. Permacoat has been applied to coaches that were brand new and those that are old. If it was applied new and re-applied during its life the Avion looks like it is brand new. Older trailers will have effective results also. Expect the finished product to look as good as when you clean and wax.