When I went to send this artwork, and its companion pieces to the people who commissioned it, the shippers deemed the work too delicate to ship, and insure. After much exploration, and discussions with helpful local framers and builders, at the art materials store, and the lumber yard, this is the solution that I arrived at. I built up the inner shell from 7 layers of foam core, cut and glued as a nest for the artwork, which is pretty sturdy in itself, on a base of illustration board. I will lay a piece of foam core over the top, and then a final piece of plywood will be screwed on top. The sides are pine furring, with L brackets. I think that this will be very sturdy. I have learned a lot about how roughly packages are treated, and how much thought and care must go into shipping. May there be blessings in our handiwork, and traveling mercies as well!