3D-printable pour moulds with a vertically split sleeve. Unscrew the two seams and open the halves to release the cast. The base forms the inside; the open top becomes the foot.
Fine concrete works too: switch the material to get concrete mix weights, checks and casting steps.
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Jesmonite–
Mix by weight–
Mould footprint–
Print heights–base · sleeve
Base and two sleeve-half STLs, plus settings and assembly instructions. Exported at full smoothness.
One numbered STL per shard, laid outer face down, plus kintsugi instructions.
Casting steps
Print the base and both sleeve halves in the exported orientation. Horizontal screw holes may need short bridges or local supports. Sand the dome, sleeve interior and mating seam faces smooth.
Coat every surface the Jesmonite touches with release agent (wax or a release spray).
Coat every surface the concrete touches with a release agent made for concrete (form-release oil or wax). Sieve the mix to 1–2 mm aggregate for thin walls.
Seat the sleeve halves around the base ridge. Clamp both vertical seam flanges with screws, nuts and washers, then tighten the base bolts. Seal the outside of both vertical seams and the base joint with plasticine. For a one-piece sleeve, just seat and bolt down.
Pour slowly down one side until the sleeve is full. Tap the mould to lift air bubbles.
Pour in layers until the sleeve is full, vibrating or tapping the mould for several minutes, longer than for Jesmonite, until bubbles stop rising.
Scrape across the top with a ruler. That surface becomes the flat foot.
Cover the top and leave the concrete in the mould for 24–48 h.
Once cured (check your Jesmonite's datasheet)Once firm, remove the base bolts and seam screws. Separate the sleeve halves sideways, then gently lift the cast off the dome. A one-piece sleeve must be lifted off first. The solid inner core still needs draft and release agent.
Keep the cast damp while it cures: wrap it in plastic or mist it daily for about a week before use.
JesmoniteConcrete is not waterproof on its own. Seal vases and planters inside before they hold water.
Kintsugi steps
Print each shard as oriented (outer face down) with tree supports under the curved underside. Print the storage box trays without supports at 10–15% infill and the lids flat face down; each pocket is numbered and has a finger notch. PETG or PLA both work; sand the visible faces if you want a stone-like finish.
Shards are numbered from the foot upwards. With Numbers on, each number is engraved on the chosen face with its top pointing to the rim; otherwise pencil it on the inside. Check the fit dry against the Assembled view.
Lightly sand the crack faces so the adhesive keys in. Join shards from the foot up with a slow-setting two-part epoxy (or a kintsugi kit's lacquer), taping each joint while it sets.
Fill the seam gap proud with epoxy putty, sand it flush, then paint the seams with gold, silver or copper powder in lacquer or gold leaf size. Plastic shards are decorative: do not use them for food.