◆ Clay

Hexagon bottle slip casting mold

A three-piece plaster mold for slip casting a hexagonal bottle vase with a sloped shoulder and hex neck.

3D render of three printed plaster-mold housings for a hexagonal bottle, orange and blue shells beside charcoal bases, with a pale blue fired hexagonal bottle in front
Clay ~2206 g Pro early access

A six-sided bottle 72 mm across the corners and 120 mm tall once fired: flat sides, a sloped shoulder easing into a narrow hexagonal neck, and a flat foot. It holds 197 ml to the brim, a bud vase, an oil bottle or a reed diffuser.

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Made with our plaster mold generator: a printed housing per plaster piece, you pour the plaster, and the plaster is the mold. It is a three-piece mold, two flat sides to each piece. The page's seam check found nothing stuck at two pieces too, but at two a pair of flat sides runs straight along the pull and drags the whole way out; at three, every side leaves its plaster at an angle. Open at the neck, mold cut 15% oversize for a 13% shrinkage slip.

The zip carries the three bases, one shell and clamp set that fits all three, the bottle as its own STL, the tool's print sheet and a recipe file for the generator.

Shown as a 3D render of the printed bases and shells with the fired piece in front, not a photo.

What you need

4
  • About 460 ml of casting slip to fill the mold (most of it pours back out)
  • Pottery plaster (No. 1 Pottery or similar), enough to fill each housing to the top of its shells
  • Mold soap or petroleum jelly, and strong rubber bands or mold straps
  • A pencil to number the plaster pieces

How to cast it

8
  1. Print the 3 bases and the one set of shells and clamps, no supports. The sheet in the zip asks for 4 or more walls and 40% gyroid, because the shells get clamped.

  2. Stand the two shells round the first base, slide the clamps over the ends, and run a thin bead of petroleum jelly along every seam. Brush mold soap over the printed master slice and the natch sockets so the plaster lets go.

  3. Sift pottery plaster into water (about 100 g of plaster to 70 g of water), let it slake for two minutes, mix for three, then pour it up to the top of the shells and tap the housing to lift the bubbles.

  4. After 30 to 45 minutes, when the plaster is warm and hard, unclamp, lift the shells off and ease the plaster piece off the base. Move the same shells and clamps to the next base and pour again.

  5. Let the plaster pieces dry for about a week somewhere warm and airy, until they feel light and no longer cool to the touch. A damp mold barely takes water out of the slip.

  6. Band the 3 pieces together with the natches seated, stand the mold mouth up and fill it to the top of the neck with slip. Top it up as the level drops.

  7. When the wall is 3 to 4 mm thick (usually 10 to 20 minutes, check at the rim), pour the slip back out and leave the mold upside down to drain.

  8. Once the cast loses its shine and pulls away from the plaster, trim the rim, open the mold and lift the piece out. Dry it slowly to bone dry, then bisque and glaze fire.

Print details

73 h 30 minPrint time
~2206 gFilament
7Printed parts
163 × 242 × 86 mmSize (W x D x H)
All print details
Print details
Cast materialClay
Printed parts7
Size (W x D x H)163 x 242 x 86 mm
Print bed needed242 x 152 mm, 86 mm tall
Filament~2206 g
Layer height0.2 mm
Infill40%
SupportsNot needed
DownloadZIP: 3 bases + one shell and clamp set (7 printed parts, STL) + bottle master (STL) + print sheet + recipe
Added2026-09-25

Pro early access until October 25, 2026, then free with any account.

Make your own plaster slip-cast mold →

Made with the free Plaster slip-cast mold generator. Upload your own model and get the same kind of mold built around it, in your browser.

Free for personal use. Selling the pieces you cast needs a commercial licence (Pro or Founder); passing on the file itself is not permitted on any plan. Full terms.

New to casting? Read the plaster mold guide.

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Questions about this design

How do I keep the hexagon bottle's sides flat as it dries?

Dry it slowly and evenly, standing on its foot, loosely covered for the first day. Flat sides pull in if the corners dry first, so if you see the corners going pale before the middle, cover it again.

Can the hexagon bottle be used as a reed diffuser?

Yes. Glaze the inside fully, since the oil will soak into bare clay and weep, and fire the clay to maturity. The 197 ml body and the narrow neck are close to a standard diffuser bottle.

Why does the hexagon bottle take longer to drain?

The neck is narrow and the shoulder is flat, so slip lingers on the shoulder. Drain it upside down at a slight angle for 20 minutes, then turn it the other way for a few more, or a thick slab builds up inside the shoulder.

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