ya do you have ready access to cheap fiberglass? if all you want is a standard size flood tray, seems like a lot to go through! I have seen someone build a DIY coliseum out of fiberglass. He was extremely talented, and it turned out awesome, i wish i still had the link. But he didnt seem to think it would affect the plants.
Standard fiberglass resin should be plenty safe for plants. In fact, I think Botanicare tables are fiberglass (the 7" deep ones; I think the thinner 4" high ones are ABS plastic).
It's PVC plasticizers (a chemical that makes PVC soft and pliable) that is the off-gassing culprit, meaning that you generally don't have to worry with "hard" plastics.
well the botanicare trays are not deep enough. i need atleast 10" deep. what im doing is a sog DWC project where im using a pvc manifold with 1" round air stones under each plant 50-70 plants per tray. right now im just doing some test runs with those 27 gallon totes you get from lowes.
i want to give the roots enough room to grow without them getting tangled together incase i need to move some around. 8 plants per tote Using 2" net cups filled with the clay balls in the totes for now.