◆ Resin

Square resin coaster mold

Two 96 mm square resin coasters per pour, 7 mm deep, with rounded corners and edge. Silicone you pour yourself.

Make your own tray mold
3D render of the printed caster for a two-cavity square resin coaster mold, with three glossy amber square resin coasters with rounded corners in front
Resin ~143 g Pro early access

A silicone mold for square resin coasters 96 mm on a side and 7 mm thick, two to a tray, with 10 mm rounded corners and a 2.5 mm rounded top edge. The front comes out of the silicone glossy and finished, and the flat back is the side you pour from.

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Made with our tray mold generator in its flexible silicone tray mode: print one part, a caster, pour a platinum silicone into it and peel it out. That silicone is the coaster mold, and resin lets go of it with a mirror face and no release agent. Each coaster takes about 64 ml of resin.

A square coaster is the best frame for a photo, a pressed flower arrangement, a map or a monogram, and four make a gift box set. At 7 mm, use a deep-pour casting resin in one go, or a coating resin in two or three thin layers. The zip carries the printed caster 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 silicone figure the tool measured.

Shown as a 3D render of the printed caster with three amber resin square coasters in front, not a photo.

Square resin coaster mold at a glance: every printed part with its size, print time, filament, print settings and the three steps to use it

What you need

4
  • About 262 ml of platinum silicone (mix it in one batch)
  • About 64 ml of deep-pour or casting epoxy per coaster
  • Pressed flowers or a sealed photo print, 85 mm square or smaller
  • Nitrile gloves, a heat gun or torch, a level surface and cork or felt pads

How to cast it

6

  1. Print the caster as exported, open side up, no supports. Turn on ironing for the top surfaces, or sand the raised shapes smooth and brush on XTC-3D: the silicone copies every layer line, and resin shows each one on its glossy face.

  2. Mix 262 ml of platinum silicone and pour it into one corner of the caster in a thin stream until it covers the shapes to the rim. Tap out the bubbles, let it cure as long as its datasheet says and peel it out. That silicone is your resin mold: platinum silicone gives resin a glossy face and needs no release agent.

  3. Set the mold on a level surface in a ventilated room, gloves on. A 7 mm coaster is a job for a deep-pour or casting epoxy in one pour. A coating (tabletop) epoxy is made for 3 mm or so: pour it in two or three layers, each once the last has gelled, or it overheats and yellows.

  4. Mix about 64 ml per coaster, stir slowly for three minutes, add colour, mica or inclusions, and pour each cavity level with the rim. Remember the side against the silicone is the top of the coaster.

  5. Pass a heat gun or torch over the surface after five minutes and again after fifteen to pop the bubbles, then cover the mold against dust and leave it 24 to 72 hours, as long as your resin says.

  6. Flex the mold and peel it off the coaster. Sand the back flat if it has a lip, add cork or felt pads, and let the coasters cure a full week before a warm mug goes on them.

Print details

4 h 50 minPrint time
~143 gFilament
1Printed parts
108 × 210 × 19 mmSize (W x D x H)
All print details
Print details
Cast materialResin
Printed parts1
Size (W x D x H)108 x 210 x 19 mm
Print bed needed211 x 108 mm, 19 mm tall
Filament~143 g
Layer height0.2 mm
Infill15%
SupportsNot needed
DownloadZIP: printed caster (STL) + one coaster (STL) + tool master (STL) + print and pour sheet
Added2026-09-27

Pro early access until October 27, 2026, then free with any account.

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Make your own tray mold →

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 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.

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Questions about this design

How do I put a photo in a square resin coaster?

Print the photo about 85 mm square so a clear rim of resin frames it, and seal both sides with Mod Podge or laminate it so the resin cannot soak in and darken the paper. Pour 2 mm of clear resin, let it gel, lay the photo face down, and fill to the top. The front of the coaster is the side against the silicone.

Why do my square resin coasters have bubbles along the corners?

Air clings to the corners of the cavity as resin flows past. Brush a thin coat of resin into the corners first, then pour into the middle and let the resin spread outward. A pass with a heat gun after five minutes and again after fifteen pops what rises.

How many square coasters does one kit of resin make?

Each coaster takes about 64 ml, so a common 500 ml kit makes seven or eight, and a 1 litre kit about fifteen, allowing for what stays in the cup. Mix one batch for every coaster you pour at the same time: topping up from a second batch can leave a visible line in clear resin.

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