The sail on the dimetrodon is made from three layers. The outside spines are maple which sandwich a walnut core.
The spines and core were machined on the CNC router to be precise, then glued together on the bench using aliphatic resin (yellow wood glue).
Wood glue creates a bond that is stronger than the wood fibers.
The sail sides and middle were sanded to 600 grit, essentially polishing the wood fibers, before being glued. The jaw of the beast is attached to the sail, and the entire work is driven up and down by a cam wheel attached to the rear axle.