After a week making the inside surfaces glossy and blue, I was back to making sawdust.
I mitred the ends of the panels with my sliding table saw, using a stop block to ensure that they were all the same length. I appreciated the fact that my carefully-painted surfaces were able to just sit on the sliding table and glide past the blade, rather than be pushed across the table and risk scratching them.
To make assembly easier, and for reinforcement, I cut mortises in the mitres with my Domino Joiner.
Using Domino floating tenons, all I had to do was get them started in the mortises, then use a mallet to drive the parts together. Alignment was guaranteed.
The floating tenons are strong, too! I first assembled the sides in pairs.
Then I put the two halves together and clamped the entire assembly with web clamps.
It was really exciting to get to this stage, but the next stage is pretty exciting too – cutting the puzzle pieces!