◆ Resin

Polyhedral dice set resin mold

Six sharp-edge dice, d4 to d20, every number engraved, cast in resin from one silicone mold you make yourself.

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3D render of the printed base with six polyhedral dice masters on sprues between the orange and blue walls, with purple resin dice in front
Resin ~185 g

A resin dice mold for one polyhedral set: a d4 with 20 mm edges and its numbers by the corners, a 16 mm d6, a d8 and a d10 about 20 mm across, an 18 mm d12 and a 20 mm d20. Every face carries its number engraved 0.7 mm deep, opposite faces add up the way real dice do, and the 6 and 9 carry a dot. Sharp edges, the look resin dice makers sell. The whole set takes about 18 ml of resin.

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Made with the box mode of our silicone mold maker, the mode the tool itself suggests for this shape. Each die hangs point down from a short tapered sprue, so in the finished mold every die is closed on all faces and fills through its top corner: the air rises out through the sprue instead of leaving a bubble on a face. A shallow channel joins the six sprue mouths, so one pour runs along it into all six. Print the base with the dice fused onto it, the two walls and the two clamps, and pour about 493 ml of silicone.

Pour clear resin with mica, alcohol ink swirls, glitter or a tiny flower inside, then ink the engraved numbers. The zip carries every printed part, the dice master as its own STL, the tool's own print-settings sheet and a recipe file for the generator.

Shown as a 3D render of the printed mold parts with a cast set of dice, not a photo.

Polyhedral dice set resin mold at a glance: every printed part with its size, print time, filament, print settings and the three steps to use it

What you need

4
  • About 532 ml of platinum silicone, Shore 20A to 30A (mix it in one batch)
  • Epoxy casting resin, about 18 ml per set, with mica, alcohol ink or glitter
  • A sharp craft knife for the one slit, flush cutters for the sprues
  • Wet sandpaper from 400 to 2000 grit, and paint or a paint pen to ink the numbers

How to cast it

7

  1. Print the base with the master fused onto it, the two walls and the two clamps.

  2. Stand the base on the table. Set each wall down a few centimetres out from it and slide it in over the table until the ridge round the base sits in the groove at its foot, then slide the clamps down over the seams. Once they are on, the walls cannot lift, and the ridge seals the bottom.

  3. Mix 532 ml of silicone in one batch and pour it into a corner, letting it rise around the master until it covers the top.

  4. Once it has cured, take the clamps off and slide the walls straight out. Each die is closed in the block, so cut one straight slit down the long side with a sharp knife, from the open face down past the bottom of the dice, open it like a book and lift the dice master out.

  5. Stand the block back inside the walls with the clamps on, which hold the slit shut. The six holes in the open face are the sprues, joined by the shallow channel.

  6. Mix the resin slowly so it takes in little air, warm it a little to let bubbles rise, and pour a thin stream into the channel so it runs into each sprue in turn. Keep pouring until every sprue is full to the top. A pressure pot, if you have one, gives bubble-free dice.

  7. Let it cure as long as the resin says, usually 24 to 48 hours. Take the walls off, open the slit and pop the dice out. Snip each sprue off close to its corner, sand the corner flat from 400 to 2000 grit wet, then ink the numbers and wipe the faces clean.

Print details

5 h 30 minPrint time
~185 gFilament
5Printed parts
186 × 53 × 69 mmSize (W x D x H)
All print details
Print details
Cast materialResin
Printed parts5
Size (W x D x H)186 x 53 x 69 mm
Print bed needed209 x 53 mm, 69 mm tall
Filament~185 g
Layer height0.2 mm
Infill15%
SupportsNot needed
DownloadZIP: 5 printed parts (STL) + dice set master (STL) + print sheet + recipe
Added2026-10-01
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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 silicone mold maker guide.

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Questions about this design

How do I ink the numbers on resin dice?

Fill each engraved number with acrylic paint or a paint pen, let it dry for a few minutes, then wipe the face with a slightly damp paper towel or a card held flat: the paint stays in the numbers and comes off the face. A coat of clear varnish over it keeps the ink from wearing off.

Why are there no bubbles on the faces of these dice?

Each die fills through its top corner, the highest point of the cavity, so air in the resin rises to the sprue and out instead of collecting under a face. Mix slowly, warm the resin a little, and a pressure pot at 40 to 60 psi makes the casts perfectly clear.

Are these dice balanced?

They are as fair as any cast resin dice: the shapes are regular solids, and opposite faces add up the same way as on commercial dice. Inclusions such as flowers or big glitter sitting on one side can bias a die slightly, so keep heavy inclusions near the middle.

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