: Zar should be available at pretty much any hardware store or home center.

: There are some other things to consider here, though. Zar doesn't really
: stick to nylon, wasn't designed as a marine coating, and isn't flexible.
: It will crack, and get abraded pretty easily.

Zar is much more durable and flexible than you make it sound. While it will scratch, it takes some effort to do any real damage. Additionally, I've never seen it crack. It sounds to me like you may be putting it on too thick. Three coats will seal the fabric well and 5 will make it smooth. Any more than that and you're simply adding unnecessary weight and making the coating less flexible.