Hi There:

We've also used Vulkem for sealing our windows, etc. The product does come in a gray color and is cheaper from a source other than an RV dealer. There are quite a few Vulkem products. The best for the job is Vulkem 116 as per the Airstream factory tech. I called the company who manufactures Vulkem (Tremco Incorporated - Mameco Division - 800-321-6412) and asked for local distributors in our area.  The real trick (as with all sealants) is in keeping a small bead to complete a neat job. I used a large syringe (one that is used in injecting seasoning into meats) without using the needle. It made a nice bead and I must say looks pretty professional for a real amateur.

Good luck,

Ann
'76 31 ft. Sovereign