I used Liquid Glass a polymer sealant, goes on easy, one can did my motorhome with 1/3 left to spare. I did 2 or 3 coats, and it seems to haveheld up well after 7-8 months. Still shines with a quick wash. Cost 18 a can locally at Pep Boys. Their web site has retail locations also- http://www.liquidglass.com/retailers.htm
This website is not affiliated with or endorsed by the Airstream, Inc. or any of its affiliates. Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.