I've done a few with my last attempt turning out very well. Here's my first and second time around around.
The slate on the bottom left was my second try, the rest were the first. The first time around I didn't get too picky, just wanted to see if I could do it. The second I put much more time in to it. I'm now in the process of making another box, push button, and a glass slate. Also have plans on trying an owl hooter. My dad has a nice little cabinet shop set up in his garage and that's a big plus. Not sure how I would do the pots for the slates without the use of his wood lathe. Once I get these new ones done I'll post some picks up.
All the wood I use is reclaimed from either pallets or trim scraps from our cabinet shop at work. The box is mahogany. I pulled a ruff cut 2"x4" about 48" from a pallet. Didn't know what I had at first but I knew it was very dense so I kept it. The push button is made from red oak that I also pulled from a pallet. I ripped the boards down to a 1/4" and then run them trough the plainer. Both striking surfaces on the push button are made from black walnut though, it came from an old barn beam. The pan call on the right is just poplar with the slate from old roof tiles. A buddy gave me a box from an old demoed roof slate. There's a mix of gray and black slate in the box. The black works the best but I think the gray would make and excellent kee kee type call, really high pitched. The final slate, on the left, I made the pot out of scrap cedar and the sound board is actually a piece of 26 ga sheet metal. I tried a few wood ones but was looking for a real raspy tone. I found online where someone was using metal for it's raspy quality and as it turns out it works great. The slate is again old black roof slate