I had no idea that you can buy smaller sheets of acrylic at Lowes! Such a helpful tip! I picked up four of these 30x36" sheets for about $20 each and then I got started on the artwork with my girls.
I found this butterfly book at an antique book store (it can be found here too).
It has about 50 color plates of butterfly sketches that I referenced to draw random butterflies on two sheets of lilac colored art paper that I cut to be just a few inches shorter than the acrylic sheets.
I outlined the sketches in black sharpie and let the girls color them in however they wanted. My two older girls used acrylic paint and Evie went with markers.
After they finished coloring in the butterflies, I mounted the paper to the back acrylic sheet with double-sided tape and then marked where I wanted my screws to go. Then I heated an extra large nail with a long match until it was hot enough to melt the acrylic. This is a much easier way to make holes in the acrylic than screwing with a drill. Acrylic is pretty brittle and can break in the drilling process, but the hot nail is easy and pretty painless!
Then all you do is thread the holes with a 1/2" long machine screw and a nut to sandwich the two boards together.
You can use picture hanging wire wrapped around the screw underneath the nut to hang your new frame.
The wire will show a little on the side middle screws, but it's not really noticeable.
I love how this project turned out and the girls really loved working on it with me! :)