◆ Concrete
Tall concrete pumpkin mold
A tall ribbed pumpkin, 125 mm high, to cast in concrete for your porch or mantel. A silicone mold kit from printed parts.
◆ Concrete
A tall ribbed pumpkin, 125 mm high, to cast in concrete for your porch or mantel. A silicone mold kit from printed parts.
A tall pumpkin 100 mm across and 125 mm high to the top of its stem: eight long lobes run from the sunken crown to a lobed foot about 63 mm across, with a straight, ridged stem on top. It is the upright shape of a carving pumpkin, and it groups well with the round and heirloom concrete pumpkins in this library for a staggered fall display.
Made with the hugging-shell mode of our silicone mold maker, the mode the site's own mold advisor recommends for a standing shape that swells above its foot. The shell follows the pumpkin about 10 mm out, so the mold takes about 471 ml of silicone. Print the base with the pumpkin fused onto it, the two shell halves and the six clamps, and pour; the flexible skin that comes out casts pumpkin after pumpkin.
Cast it in fine concrete or Jesmonite, about 1340 g in concrete, through the open foot of the upturned skin. Leave it raw, wash it white, or paint it in a heritage green with a gold stem. Plaster and resin work in the same mold for indoor decor. The zip carries every printed part, the pumpkin 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 pulled apart around the master, not a photo.
Print the base, which has the pumpkin master already fused onto it, the two shell halves and the six clamps (all six are in clamps.stl). No supports.
Stand the base plate on the table, set each shell half down a few centimetres out from it and slide it in until the ridge round the plate sits in the groove at its foot. Push the six clamps over the seams: the shells cannot lift after that, and the ridge seals the bottom.
Tape the outside seams or run a bead of hot glue along them, because silicone finds every gap.
Mix 510 ml of silicone in one batch and pour it through the pour hole in the top of the shell in a thin stream until the hole is full, so it rises round the lobes and over the stem.
Once it has cured, take the clamps off and slide each shell half straight out. The silicone skin is open only at the foot, which is narrower than the pumpkin, so cut ONE slit with a sharp knife along a crease, from the foot to about two thirds of the way up, peel the skin open and lift the master out. In a crease the seam line hides.
Put the skin back in the shell halves with the clamps on, and stand the shell upside down on the fins on its roof: the shell holds the slit shut and keeps the skin round, and the open foot is now on top.
Mix a fine concrete or Jesmonite to a thick pour. Brush a thin first coat into the stem and the creases, fill slowly down one side, vibrate the shell for a full minute to raise the air, and strike the foot flat.
Leave it a day, take the shell off, open the slit and peel the skin back from the foot toward the stem. Let the pumpkin cure for a week, sand the foot flat, add felt pads, and paint or seal it.
Print details
| Cast material | Concrete |
|---|---|
| Printed parts | 9 |
| Size (W x D x H) | 138 x 146 x 148 mm |
| Print bed needed | 146 x 101 mm, 148 mm tall |
| Filament | ~640 g |
| Layer height | 0.2 mm |
| Infill | 15% |
| Supports | Not needed |
| Download | ZIP: 9 printed parts in 4 STL files + pumpkin master (STL) + print sheet + recipe |
| Added | 2026-09-26 |
Pro early access until October 26, 2026, then free with any account.
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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.
Because the pumpkin is 100 mm across and its foot only about 63 mm, and the foot is the only opening in the skin. Cut one slit along a crease from the foot to about two thirds of the way up, and the skin opens enough to let the pumpkin out; the printed shell holds it shut for every pour, and the line hides in the crease.
Demold after 24 hours in a warm room, or 48 if it is cool, since the tall stem sits at the bottom of the mold where the concrete is last to firm up. Then let it cure for a week before it goes outside, and keep it out of frost for its first month.
Yes. Concrete shrugs off rain, and at about 1340 g it will not blow over. Seal it with a clear concrete sealer so it does not stain from wet leaves, and bring it in before hard frost if water can sit in the crown, where freezing can chip it.
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