There are many options. I have used polyester resin before and it is very smelly and you want to be careful where you buy it from. I bought some from a home center and it was old and the catalyst did not kick off the resin all the way and it stayed sticky, never getting quite hard. Ended up sanding off and redoing[:@] Same goes for epoxy, make sure it's fresh. Here is a link for another tecnique
http://www.youtube.com/watch?v=1rcKyCMDBJE
This guy is quite the scale builder and he posts on here alot. He did a heck of a job on this Hellcat
http://www.rcuniverse.com/forum/m_25..._1/key_/tm.htm