◆ Crayons
Star crayon mold
Twelve chunky star crayons from broken old crayons, melted in the oven in a silicone tray you make.
◆ Crayons
Twelve chunky star crayons from broken old crayons, melted in the oven in a silicone tray you make.
A silicone tray for twelve puffy star crayons, each 38 mm across and 12 mm thick with rounded points that are hard to snap. About 8 ml each, a chunky size small hands grip easily, and every point makes a fine line while the flat back fills in large areas.
Made with our tray mold generator in its flexible silicone tray mode: print the caster, pour a heat-proof platinum silicone into it and peel out the tray. The crayons melt in that silicone in the oven at 110 to 135 C; the printed caster never goes in the oven, since PLA softens at about 60 C.
It is the classic way to give broken crayons a second life, and stars in mixed colours make a class party favour or a stocking filler. The zip carries the printed caster exactly as the tool exported it, one star on its own as an STL, the master uploaded to the tool, and a print and pour sheet with the silicone figure the tool measured.
Shown as a 3D render of the printed caster with four red star crayons in front, not a photo.
Print the caster as exported, open side up, no supports. It never goes in the oven: PLA softens at about 60 C.
Pour 288 ml of a platinum silicone rated for 200 C (400 F) or more into one corner in a thin stream, letting it rise over the shapes to the rim. Tap out the bubbles, let it cure and peel it out: that silicone is the crayon mold.
Soak old crayons in warm water for ten minutes, peel off the paper and break them into pieces about 1 cm long. Sort them by colour, or mix colours for swirled crayons.
Set the silicone tray on a baking sheet. Fill each cavity to the top with pieces and heap it a little: they shrink as they melt.
Bake at 230 to 275 F (110 to 135 C) for 10 to 20 minutes, until every piece has melted. Hotter makes the wax separate into a white film on top.
An adult lifts the sheet out. Let the crayons cool for 30 minutes, give the tray 10 minutes in the freezer, then flex it and pop them out. Keep this tray for crafts, never food.
Print details
| Cast material | Crayons |
|---|---|
| Printed parts | 1 |
| Size (W x D x H) | 177 x 130 x 21 mm |
| Print bed needed | 178 x 130 mm, 21 mm tall |
| Filament | ~126 g |
| Layer height | 0.2 mm |
| Infill | 15% |
| Supports | Not needed |
| Download | ZIP: printed caster (STL) + one crayon (STL) + tool master (STL) + print and pour sheet |
| Added | 2026-09-26 |
Made with the free Tray mold generator. Upload your own model and get the same kind of mold built around it, in your browser.
Free download. Opens the Thingiverse listing in a new tab.
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 ice cube tray mold guide.
Mix two or three colours in each star, using pieces of similar size, and do not stir. They blend a little at the edges as they melt, which gives the swirl. Colours next to each other on the colour wheel, like red, orange and yellow, stay bright; opposites turn brown where they meet.
The oven was too hot, so the wax separated from the pigment and floated up. Stay at 230 to 275 F (110 to 135 C) and take the tray out as soon as the last piece has melted. The film scrapes off with a fingernail and the crayon still works.
They are as safe as the crayons you melted: use crayons marked non-toxic, and an adult handles the oven and the hot tray. At 38 mm they are too big to swallow whole, but supervise small children, since a broken point is a choking size.
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