How to make a cast of any object
Get a 3D model of the object (scan it, download one, or model it), turn the model into a printable two-part mold with a free mold generator, print the mold, then pour a casting material into it. Start with plaster of Paris — it's cheap, mixes with water, sets in under an hour, and forgives every beginner mistake.
Step 1: get a 3D model of the object
Scan it, download it, or model it
Modern casting starts digital — instead of pressing your object into clay, you get it as an STL file. Three routes, easiest first:
- Download it. For figurines, ornaments and common shapes, someone has already uploaded a model to Printables, Thingiverse or MakerWorld.
- Scan it. Free photogrammetry apps turn a minute of phone-camera footage of a small object into a mesh.
- Model it. For simple geometric shapes, ten minutes in Tinkercad does the job.
Steps 2–3: generate & print the mold
Generate the mold
Drop the STL into the free Meshcast mold generator. It builds a print-ready two-part mold around your model automatically — parting line, alignment keys and pour hole included — right in your browser, no CAD and no signup. The full walkthrough is in STL to mold.
Print it
Print both halves flat-face-down in PLA or PETG: 0.2 mm layers, 3–4 walls, 15–20 % infill. A palm-sized mold prints overnight. Dial in the details with best print settings for molds.
Step 4: pick your casting material
Match the material to the project
The mold doesn't care what you pour — the material choice is about what the cast is for:
| Material | Best for | Difficulty & cost | Guide |
|---|---|---|---|
| Plaster | Decor, first casts, learning | Easiest · cheapest | Plaster casting → |
| Wax | Candles | Easy · cheap | Candle making → |
| Resin | Detail, strength, jewelry | Medium · pricier | Resin casting → |
| Soap | Gifts, bathroom | Easy · cheap | Soap making → |
| Concrete | Planters, outdoor, heavy decor | Easy · cheapest | — |
Beginner's pick: plaster. A bag costs a few dollars, it mixes with plain water, sets in under an hour, and if the pour fails you shrug and mix another cup.
Step 5: pour, cure, demold
The pour itself
Mist the cavity with mold release, clamp the halves with rubber bands, and pour slowly through the hole. Tap the mold a few times to release trapped air, then wait the full cure time — demolding early is the #1 beginner mistake. Pry the seam open, clean the flash line off the cast, and you're done.
FAQ
What is the easiest casting material for beginners?
Plaster of Paris. It costs a few dollars a kilo, mixes with plain water, sets in under an hour, is non-toxic, and demolds easily. If a pour goes wrong you are out pennies — perfect while you learn.
Do I need a 3D printer to make a cast?
For this workflow, yes — the mold is 3D printed. No printer at home? Generate the mold file for free, then have a local library, makerspace or online print service print it for a few dollars.
How do I make a cast of an object I own?
Turn it into a 3D model first. Free photogrammetry apps can scan small objects with your phone camera, and for common items someone has usually already uploaded a model to Printables, Thingiverse or MakerWorld.
Why is my cast stuck in the mold?
Usually a skipped release agent, demolding too early, or undercuts — surfaces that hook behind the parting line. Apply mold release before every pour, wait the full cure time, and reposition the seam if a feature keeps catching.
Made by @meshminds3d. Got stuck? Email a photo and I'll help you debug.