A printed tray for six sidewalk chalk sticks, each 110 mm long and 22 mm wide, with a rounded back that sits well in a small hand and a pointed tip for drawing lines.
Made with our tray mold generator in its rigid tray mode: print the tray, wipe in a release agent and pour coloured plaster straight in. Homemade chalk is plaster of Paris, water and paint, a good rainy-day project with children before a sunny one.
The zip carries the tray exactly as the tool exported it, one chalk stick on its own as an STL, the master uploaded to the tool, and a print and pour sheet with the volume of each cavity.
Shown as a 3D render of the printed tray with three blue chalk sticks in front, not a photo.
What you need
- Plaster of Paris, about 20 ml of mix per stick
- Tempera or poster paint for colour
- Cooking spray or petroleum jelly as release
How to cast it
- Print the tray as exported, cavities up, no supports. PLA is fine: plaster only gets warm as it sets.
- Wipe a thin film of mold release, petroleum jelly or cooking spray into every cavity, including the fine detail.
- Mix casting plaster to a pouring cream (add pigment now if you want colour), fill each cavity and tap the tray on the table for a minute to lift the bubbles.
- Leave it for an hour until the plaster is warm and hard, then flex the tray corners and tip the pieces out. Let them dry for a day before you add oils or paint.
| Cast material | Plaster |
|---|---|
| Total print time | 10 h 56 min |
| Printed parts | 1 |
| Size (W x D x H) | 124 x 183 x 18 mm |
| Filament | ~133 g |
| Layer height | 0.2 mm |
| Infill | 15% |
| Supports | Not needed |
| Printer | Sliced with PrusaSlicer 2.7.2: 0.4 mm nozzle, 0.2 mm layers, 3 walls, 15% infill, MK3-class speeds. You pour straight into this tray, so PLA is fine: plaster and concrete only get warm as they set. No supports. |
| Download | ZIP: printed tray (STL) + one chalk stick (STL) + tool master (STL) + print and pour sheet |
| Added | 2026-09-24 |
Pro early access until October 24, 2026, then free with any account.
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.
Made with the free ice cube tray mold generator. Upload your own model and get the same kind of mold built around it, in your browser.
New to casting? Read the ice cube tray mold guide.
