Mould and cast, or print each one
These are usually presented as rival hobbies and they are better understood as two halves of one workflow — a very large number of people print an original and then mould it. The genuine decision is per batch rather than per person: how many copies, in what material, and how likely is the design to change. Get those three answers and the choice makes itself.
The decision this settles: You need more than one of something — game pieces, parts, props, jewellery blanks, twenty of a thing you designed. You could print each copy, or make a mould from one original and cast the rest. You want to know where the crossover is.
Where they genuinely differ
Marked per row rather than overall — “better” only means something relative to a specific dimension.
| Point of difference | Mould making | 3D printing |
|---|---|---|
| Cost of the first copyThe fixed cost that sets the crossover. Below about five copies, printing each is almost always cheaper. | High. Silicone for a small mould is £25–£45 before you cast anything | Low. Filament for a small part is pennies, once you own the printerAdvantage here |
| Cost of the twentieth copyAnd the reason the crossover exists. Casting is a batch technology; printing is a one-off technology repeated. | Very low, and the mould keeps going for dozens moreAdvantage here | The same as the first, every time, plus the hours of printer time |
| Time per copyUnderestimated by people who have only printed. A print farm solves it with money; a mould solves it with silicone. | Minutes to pour, then a cure. Twenty small casts is an afternoonAdvantage here | Hours per part, and they are usually sequential rather than parallel |
| When the design might changeThe decisive axis while you are still iterating. Mould only what you have stopped changing. | Punishing. A changed design means a new mould and the old silicone is scrap | Trivial. Change the file and print againAdvantage here |
| Geometry you can producePrinting simply does shapes casting cannot. It is also why printing an original and then moulding it hits a wall on some designs. | Limited by undercuts. Deep traps mean a split mould, and past a point they mean it cannot be moulded at all | Almost unlimited with supports, including internal voids nothing can be moulded aroundAdvantage here |
| Surface and materialThe reason miniature and prop makers mould rather than print at volume: the cast surface needs no work and the material is chosen for the job. | Smooth straight from the mould, and you can cast resin, plaster, wax, concrete, chocolate or metalAdvantage here | Layer lines on almost everything, and you get the material the printer takes |
| Learning curve and failure modesA failed print is a wasted evening. A failed mould is wasted silicone and sometimes the original sealed inside it. | Judgement about a specific object — reading undercuts, choosing a parting line — plus chemistry that fails invisibly when contaminated | Machine tuning: adhesion, temperature, supports. Failures are visible and mostly recoverableAdvantage here |
| SafetyThe comparison flips entirely if the printing in question is resin rather than filament — then both columns are chemistry. | Silicone is benign; polyurethane rubbers and resins are isocyanate chemistry and sensitise, which needs real ventilation | Filament printing is comparatively benign. Resin printing is a different matter and closer to the casting columnAdvantage here |
Mould making
Somebody making one to five of something, still changing the design, or working with geometry full of undercuts
Print each one. The setup cost of a mould is not repaid at that quantity, and a design that is still moving makes a mould obsolete the day after you pour it.
More on Mould making3D printing
Somebody making ten or more of a settled design, wanting a smooth surface or a material the printer cannot produce
Mould the original and cast the rest — and print the original, which is what most people actually end up doing. Budget for real ventilation if you cast polyurethane rather than silicone.
More on 3D printingLast reviewed 2026-08-17. HobbyHQ does not declare a winner in comparisons — why.