How do I attach rocks and stones to fiberglass?

When a neighbor's whirlpool brokedown they decided they no longer wanted the tub. they took it up and threw it away. Being into recycling I took the tub and buried it up to the rim in the ground and using all the steps used to put in a pool liner. I have my rocks and have banked the sides so that the tub will work as a pool but now I'm not sure what is the best mortar to use to adhere the rocks to the rim and the upper foot of the tub walls. Please answer as quickly as possible as I want to finish before my family reunion this summer. Thank you.

camb008 years ago
Epoxy is def your best bet and then you can point round the edges (motar in the remaining gaps)
Gorfram8 years ago
Epoxy. Fiberglass is glass fibers embedded in an epoxy matrix.