I buy the board already cut to that size and back it with a piece of foam that fits the back. Some of the screws and longer than the board is deep and I find it easier to do it this way rather than find shorter screws or file off the screws. I keep it all together with felt and staple gun.
The verdict is he liked it! Henry was very sad that it is no longer at our house since he loved playing with the phone. He had many conversations on it. My brother-in-law was going to come up with a way to hang it so the kids don't keep knocking it over.
I'm currently working on a few other projects so hopefully there will be another Tada! soon.
