Epoxy doesnt stick to cured epoxy either so if you are going to mold it in layer you have to pour it just before it cures.
Meny pages back someone reported from that german forum Peters CNC-Ecke. You can see that everyone that use E/G have a steel frame as reinforcement.
You must register to see pictures. I can post more pictures here if you want.
Some very good topics:
http://5128.rapidforum.com/topic=110773130998
http://5128.rapidforum.com/topic=110772920369
http://5128.rapidforum.com/topic=110773689090
http://5128.rapidforum.com/topic=110773130998