The lid and the bottom are 4 mm solid. The sides were mitred on the table saw then fine tuned on my shooting board. There is no biscuit or loose tongue to strengthen the joint as I new I was going to mould through it so instead I will add mitre keys to maintain strength. The inside was taped before glue up so any glue would not stick so final clean up should be quick and easy. I recon a couple more hours and I should be finished.
Keep you posted on progress.