◆ Clay

Mug slip casting mold

A two-piece plaster mold for slip casting a 365 ml straight mug body. Add your own pulled or cast handle.

Make your own plaster slip-cast mold
3D render of two printed plaster-mold housings for a mug body, orange and blue shells beside charcoal bases, with a cream fired mug body in front
Clay ~1342 g Pro early access

A straight mug body 82 mm across and 92 mm tall once fired, with a gentle belly and a rounded foot. It holds 365 ml to the brim, about 300 ml as a drink, which is the everyday mug size.

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Made with our plaster mold generator: a housing for each plaster piece, you pour the plaster, and the plaster is the mold. A turned body splits cleanly in two, so it is a two-piece mold open at the rim. The mold is cut 15% oversize for a 13% shrinkage slip. There is no handle on purpose: a handle locks a two-piece mold, so potters cast the body and join a pulled or separately cast handle at leather hard.

The zip carries the two bases, one shell and clamp set that fits both, the mug body 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 710 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
  • Clay for the handle, and a little slip to join it

How to cast it

9

  1. Print the 2 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 2 pieces together with the natches seated, stand the mold mouth up and fill it to the brim 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.

  9. Join the handle while the body is leather hard: score both faces, dab on slip, press the handle on and smooth the joint.

Print details

44 h 40 minPrint time
~1342 gFilament
6Printed parts
176 × 210 × 104 mmSize (W x D x H)
All print details
Print details
Cast materialClay
Printed parts6
Size (W x D x H)176 x 210 x 104 mm
Print bed needed210 x 165 mm, 104 mm tall
Filament~1342 g
Layer height0.2 mm
Infill40%
SupportsNot needed
DownloadZIP: 2 bases + one shell and clamp set (6 printed parts, STL) + mug 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 put a handle on the slip cast mug?

Pull a handle from the same clay, or cast one in a small separate mold, and let it stiffen to the same leather hard state as the body. Score both faces, add a little slip, press it on and blend the joint. Dry the mug slowly under plastic for a day so the handle does not crack off.

How thick should the mug wall be?

Three to four millimetres is right for a mug: strong enough for daily use, light in the hand. In a dry plaster mold that usually takes 12 to 20 minutes. Cut a sliver at the rim to check before you pour the slip out.

Is the slip cast mug food safe?

That depends on the clay, the glaze and the firing, not on the mold. Use a food safe glaze on the inside, fire it to the temperature the clay and glaze are rated for, and the mug is as food safe as any other.

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