There are a number of systems used by the fabric covered airplane crowd to finish dacron, which includes adhesives, primers, UV protection and topcoats. Have a look at the Aircraft Spruce site. for a cheaper but probably less durable solution, some people just use oil base paint. I covered one with a RV roofing treatment clled "snow cote " or somesuch and finished with marine enamel. If you want lots of advice (and controversy) get on the baidarka mail list, and visit their archives. You'll find lots of folks building skin-on-frame by lots of methods.

Have fun!