Build a hard slab box

Hard slab construction is like carpentry with clay. The slabs need to be stiff (leather-hard) so they hold their shape during assembly.

Steps

1. Roll four walls and one base slab (~6 mm thick)
2. Let them firm to stiff leather hard (holds shape, doesn't bend easily)
3. Score, slip, and assemble into a box with clean 90° joins
4. Reinforce every interior corner with a thin coil pressed into the seam

Quality check

• All corners are 90° (use a square or the edge of a book)
• No gaps visible at any join
• Interior coil reinforcement is smoothed flush
• The box sits flat without rocking