How to Make a Cardboard Treasure Box
Cut an 8×5×3.5 inch cardboard box and a separate rounded lid. Cardboard, glue, knife, mat.
What You'll Need
- Corrugated cardboard (shipping or moving box)
- PVA craft glue or hot glue
- Craft utility knife
- Self-healing cutting mat
- Metal ruler 12 inch
- HB pencils (pack)
Use a box you already have; buy glue only if you need it.
Default box: 8 inches long × 5 inches wide × 3.5 inches tall (20 × 13 × 9 cm), with a separate rounded lid (2 inch / 5 cm rise). Moving-box or shipping cardboard. Plan 1–2 hours plus dry time. This is the box only — do not buy jewelry to put in it.
Cut on a mat, blade away from your body. Several light passes beat one hard pass. Kids need an adult on the knife.
Mark the pieces
Write the size (8 × 5 × 3.5 inches, lid rise 2 inches) on scrap first, then mark on cardboard:
• Base: 8 × 5
• Front and back: two pieces 8 × 3.5
• Sides: two pieces 5 × 3.5. If the sides sit inside the long walls, shorten the 5 inch edges by twice the cardboard thickness so the outside stays 8 × 5.
• Lid ends: two identical pieces, 5 inches wide, with a 2 inch high arch on top of a 1/2 inch (12 mm) straight skirt.
• Lid wrap: one rectangle 8 inches × the arch length (about 6.5 inches / 16 cm — measure your arch with a string).
Cut the pieces
Cut straight lines with the knife against the metal ruler. Cut the two arches slowly. Dry-fit the five box pieces and the three lid pieces before you glue.
Glue the box
Glue the front and back onto the base, standing them on edge. Glue the sides in. Check square with the ruler. Masking tape on the outside holds corners until the PVA sets.
Peel the tape after the joints stop flexing. Don’t load the box until then.
Build the rounded lid
Glue the lid wrap to the two arched ends so you get a separate shell that sits on the box. If you want a hinge, run a strip of tape along the back wall and the back edge of the lid after the glue dries. Leave the lid empty of beads and costume jewelry — those are not part of the build.
