Bryris

Thinned out expoxy does work well and I have used it on several of my models models.  Use 70% to 90% isoproply (rubbing alchol) from the drug store for thinning.  I'm not sure of the mix ratio (depends on the epoxy) so just add a little at a time until you get something with the consistancy of paint.  Thinning adds to the dry time so plan to leave it over night.   

Another option is to by a clear dope (airplane paint) from the hobby shop.  Typically available in clear or colors.  Read the lable to make sure it is fuel proof.   If you by the colored dope it can be used to cover small damaged areas that crop up after some flying.