◆ Concrete
Ripple concrete coaster tray mold
Four round concrete coasters with ripple grooves, cast straight into a printed tray.
◆ Concrete
Four round concrete coasters with ripple grooves, cast straight into a printed tray.
A printed tray for four round coasters, each 95 mm across and 10 mm thick, with shallow concentric ripples on the face and a smooth band round the edge, like a stone dropped in still water.
Made with our tray mold generator in its rigid tray mode: print the tray, wipe in release and pour concrete, Jesmonite or plaster straight in. The ripples are shallow and sloped, so a cup still sits level and the cast lifts out of the rigid tray.
The zip carries the tray exactly as the tool exported it, one coaster 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 concrete coasters in front, not a photo.
Print the tray as exported, cavities up, no supports. PLA is fine.
Wipe a thin film of mold release or cooking oil into every cavity, including the grooves.
Mix a fine concrete or Jesmonite to a thick pour, fill each cavity, and vibrate it out: tap the tray on the table or hold a sander against the side for a minute until no more bubbles rise.
Cover the tray and let it cure for 24 hours, then flex the tray and tip the pieces out. Sand the back flat, and seal them once they have dried for a few days.
Print details
| Cast material | Concrete |
|---|---|
| Printed parts | 1 |
| Size (W x D x H) | 209 x 209 x 16 mm |
| Print bed needed | 209 x 209 mm, 17 mm tall |
| Filament | ~207 g |
| Layer height | 0.2 mm |
| Infill | 15% |
| Supports | Not needed |
| Download | ZIP: printed tray (STL) + one coaster (STL) + tool master (STL) + print and pour sheet |
| Added | 2026-09-24 |
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.
Glue a thin cork sheet or four felt pads to the back once the coaster has cured. Sand the back flat first with coarse paper on a flat board; the poured side is never quite level.
Scatter small chips of coloured Jesmonite, glass or stone into the empty tray before pouring, or stir them into the mix. After demolding, sand the face with wet paper to open the chips up. Keep the chips out of the ripple grooves or they fill them.
Unsealed, yes: concrete drinks water and coffee. Seal the face with a water-based concrete sealer after a week of curing and it wipes clean. A sealed coaster still absorbs a little, which is why a cold glass does not leave a puddle on it.
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