Hi,
You can check out the "how to" on my site. There is a picture of my finished tank in the post right after this one.
When I built my tank I didn't use any fixative to hold the wood terraces in place. I think that if you are housing box turtles in the tank that they would quickly dig up and demolish anything held together without a type of glue. Who knows, it may work!
One thing I worry about is the filtration system if you try to do something naturalistic. Turtles poop A LOT and they LOVE to "go" in the water. Having a simple water dish, or even a shallow litter box full of water is not as decorative, but its a heck of a lot easier to clean! I have 2 russians and a Bell's hingeback. They live in an outside enclosure in the summer, and a large, plastic bottom rabbit cage in the winter. They are MESSY little buggers, but really cute. (The russians are 16 and 10 years old, the Bell's is a WC, unknown age).

Just my 2 cents...
Good Luck,
Kelly
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Kelly Affonce
DeKeaff Exotics
www.dekeaffexotics.com