◆ Clay

Christmas ornament slip casting mold

A three-piece plaster mold for slip casting a ribbed 72 mm Christmas bauble with its hanging neck.

Make your own plaster slip-cast mold
3D render of three printed plaster-mold housings for a ribbed Christmas ornament, orange and blue shells beside charcoal bases, with a white fired ribbed bauble in front
Clay ~1758 g Pro early access

A round Christmas ornament 75 mm across and 79 mm tall once fired: a ball with twelve raised ribs running pole to pole, a small flat to stand it on while it dries, and a short neck with a 12 mm opening for a metal bauble cap.

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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. The page's seam check found a little stuck at two pieces (about 3% of one piece, where the ribs cross a seam) and nothing at three, so it is a three-piece mold with the seams between ribs. It casts through its own neck, and the mold is cut 15% oversize for a 13% shrinkage slip.

Ceramic ornaments are a Christmas market staple and a whole tree's worth comes out of one mold. The zip carries the three bases, one shell and clamp set that fits all three, the ornament 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

5
  • About 300 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
  • Metal bauble caps with a 12 mm plug
  • 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

58 h 40 minPrint time
~1758 gFilament
7Printed parts
167 × 194 × 88 mmSize (W x D x H)
All print details
Print details
Cast materialClay
Printed parts7
Size (W x D x H)167 x 194 x 88 mm
Print bed needed195 x 156 mm, 88 mm tall
Filament~1758 g
Layer height0.2 mm
Infill40%
SupportsNot needed
DownloadZIP: 3 bases + one shell and clamp set (7 printed parts, STL) + ornament 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 thin should the ceramic Christmas ornament be?

Thin: 2 to 3 mm, so it is light on a branch. In a dry mold that is often only 5 to 10 minutes. Pour it out early, check a sliver at the neck, and fill again for a few minutes if it is too thin.

How do I hang the slip cast ornament?

The neck takes a standard metal bauble cap with a 12 mm spring plug. Press it in after the glaze firing. Keep the neck free of glaze, or the cap will not seat.

Can I glaze the whole ornament?

Glaze everything except the small flat it stands on and the neck, and fire it on that flat. A bauble glazed all over needs a stilt or to hang from a wire in the kiln, which is more trouble than it is worth.

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