Sculpture Resin Needed

I have interests in building outdoor sculptures. I had worked with ester/epoxy resins that do a good job. I am hoping for a natural source resin, preferably for this intended use. I understand there are exterior coatings that will boost the water repellency. I would hope to acquire enough resin (and coating) for a few smaller test sections. With future interests in a producing a five square meter sculpture barring a useable resin. I will combine wood for increased rigidity, hemp or kenaf/jute for fiber substance. Similar to glass/fiber composites of today. Thanks for any help.