◆ Concrete
Concrete staircase card holder mold
A concrete card holder shaped like a little staircase, with a slot for a business card, postcard or photo on the top step.
◆ Concrete
A concrete card holder shaped like a little staircase, with a slot for a business card, postcard or photo on the top step.
An architectural concrete card holder 110 mm wide and 64 mm deep: three steps rising to the back, 12, 24 and 38 mm tall, and across the top step a slot 95 mm long, 4 mm wide at its floor and 16 mm deep, its back wall leaning back 8 degrees so whatever stands in it leans at an easy angle. It holds a business card, a postcard, a photo, a place card or a small print. Every edge is rounded and every inside corner filleted, so the steps do not chip. It is 202 ml, about 444 g in concrete.
Made with the box mode of our silicone mold maker in its rectangular shape, the mode the tool itself suggests: it sits low and wide, so a silicone block you slit open once releases it. The slot becomes a thin silicone blade standing in the block. Print the base with the holder fused onto it, the two walls and the two clamps, and pour about 562 ml of silicone.
Cast it grey for a desk or a reception counter, white Jesmonite for wedding place cards, or terrazzo for a shop. The zip carries every printed part, the holder 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 mold parts pulled apart around the master, not a photo.
Print the base with the master fused onto it, the two walls and the two clamps.
Stand the base on the table. Set each wall down a few centimetres out from it and slide it in over the table until the ridge round the base sits in the groove at its foot, then slide the clamps down over the seams. Once they are on, the walls cannot lift, and the ridge seals the bottom.
Mix 605 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 off and slide the walls straight out. Cut one straight slit down the back of the block with a sharp knife, from the open face to about 10 mm short of the top, open it like a book and lift the master out.
Turn the block over and stand it back inside the walls with the clamps on, which hold the slit shut. The opening is the foot of the holder, with the thin silicone blade for the slot standing in it.
Mix a fine concrete or Jesmonite to a fluid pour, fill slowly so it runs down both sides of the blade at once, tap the walls for a minute to raise the air and strike the foot flat.
Leave it to cure for a day, take the walls off, open the slit, peel the silicone back and lift the holder straight up off the blade. Sand the foot flat, add felt pads and seal it.
Print details
| Cast material | Concrete |
|---|---|
| Printed parts | 5 |
| Size (W x D x H) | 139 x 92 x 76 mm |
| Print bed needed | 162 x 93 mm, 76 mm tall |
| Filament | ~308 g |
| Layer height | 0.2 mm |
| Infill | 15% |
| Supports | Not needed |
| Download | ZIP: 5 printed parts (STL) + card holder master (STL) + print sheet + recipe |
| Added | 2026-10-01 |
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.
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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 silicone mold maker guide.
Anything up to about 4 mm thick: a business card or a short stack of them, a postcard, a photo print, a place card, a small art print in a thin card mount. The slot is 95 mm long, so a US 89 mm or EU 85 mm business card stands in it landscape, and a postcard or a 10 x 15 cm photo stands portrait or landscape.
Yes, it was made with that in mind: cast one per table in white Jesmonite or a pale concrete, write the table name on a card and stand it in the slot. It weighs about 444 g, so it does not blow over outside, and guests can take it home after.
Because the silicone that forms it is a thin blade, and a stiff mix pushes it to one side. Pour a fluid mix slowly over the blade so the concrete rises evenly on both sides, and the slot comes out straight. Jesmonite flows best of all for this.
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