A hexagon coaster 100 mm across the flats and 10 mm thick, with three nested hexagon grooves on the face, a chamfered edge and a slight draft so every cast lifts out.
Made with the box mode of our silicone mold maker, which the site's own mold advisor ranks first for a flat shape like this. Print the base with the coaster fused onto it face up, the walls and clamps, pour about 504 ml of silicone, and the block you get is an open-face coaster mold: fill it with concrete, Jesmonite, plaster or resin and strike it flat.
The zip carries every printed part, the coaster 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 parts and the coaster, not a photo.
What you need
- About 544 ml of silicone (mix it in one batch)
- Concrete, Jesmonite, plaster or resin: each cast is 84 ml
- Tape or a hot glue gun for the wall seams
- Felt pads for the finished coasters
How to cast it
- Print the base with the master fused onto it, the two walls and the two clamps.
- Stand the walls on the base, slide the clamps over the corners, and seal the outside seams with tape or hot glue.
- Mix 544 ml of silicone in one batch and pour it into a corner, letting it rise around the master until it covers the top.
- Once it has cured, take the clamps and walls off and pull the silicone block off the master. That block is your mold.
- Turn the block over: the opening is the back of the coaster. Fill it, tap the sides to raise the air, strike the back flat and demold once it has set.
| Cast material | Concrete |
|---|---|
| Total print time | 15 h 33 min |
| Printed parts | 5 |
| Size (W x D x H) | 178 x 162 x 44 mm |
| Filament | ~201 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. These parts only hold liquid silicone while it cures, so PLA is fine. No supports. |
| Download | ZIP: 5 printed parts (STL) + coaster master (STL) + print sheet + recipe |
| 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 silicone mold maker generator. Upload your own model and get the same kind of mold built around it, in your browser.
New to casting? Read the silicone mold maker guide.
