It is looking good!

Bill is 100% right patience is the key with using Spray foam for the background. I have found that if you are wanting to make it thick in places it is best to spray a thin layer and let it cure for 24 hours then spray another layer and let it cure.

Another thing to keep in mind with using silicone as the adhesive for your background covering is that you really only get 1 shot at covering the background good. The silicone will not stick to itself when you try to apply additional coats. It may look good, but it WILL peal away and start falling off over time. I hate to suggest it, but I would suggest you count this first run at the background as a test and maybe start over. Now that you know how the foam expands and what to expect. You will get a much more durable end product this next time.

Another thing to think about is what is going to hold your Background in place once it is in the tank? With it being built out of the tank you really need something to hold it in place so it doesn't fall over randomly and potentially hurt your frogs. I built part of the background for my current build out of the tank, but once the pieces were fit into the tank I used more spray foam to basically glue them into place.

Here is a link to my thread incase you want to see what I ended up doing.

http://www.frogforum.net/vivarium-te...d-journal.html

I will be following your build along with you and can't wait to see how your vision comes together! Builds are so much fun!! (and addicting lol)