Expanding foam 3d background

Hello all,

I just had some general questions about DIY foam backgrounds. I'm creating a background on some plywood for a PVC enclosure. I was wondering what your opinions were for the spray foam I used, and the concrete/grout that I use as well. Is there anything I need to steer away from that is toxic to BP's?? I will appreciate any advice, thank you!

I wouldn't use plywood, it's too heavy. You could use styrofoam sheet, if you dont want to do it directly onto the pvc. The expanding foam to use is Great Stuff. And I use GE silicone to spread over the foam then cover with coco fiber, but if you want a concrete / rock look then I'd recommend following this guys method. This is the best looking rock background I've ever seen:

(Click the first link in the post, but the pictures are messed up, so I linked this one so you could see)
https://www.dendroboard.com/forum/me...#/topics/69174

He uses underlayment cement.