Originally Posted by lsbrodsky
I was told it is Sikaflex, a one part polyurethane adhesive, sealant. You cab find it at boating places like West Marine.
There are six different compounds each bearing the Sikaflex name. Three of them are primers, and one is a two-component system. One is only available in white (but cures to a light gray color, subject to yellowing as it ages).
The one you want is probably Sikaflex 15LM. It's also available in colors, so you can get Sikaflex 15LM in Aluminum Gray as well as in Black and other colors (but avoid lighter colors; they tend to yellow as they age). No primer required for non-porous surfaces. Here's a link to the product data: