Moulds and casting · 2026
3D printed masters for silicone moulds
Can the original for a silicone mould be 3D printed?
Yes: a maker prints the master (the original part), you make a silicone mould from it and cast copies in resin, plaster, wax, soap, concrete or chocolate. Use resin for small, detailed parts, because silicone copies everything, layer lines included; FDM for large ones. A resin piece about 7.5 cm tall costs €15–€40, excluding VAT and shipping. If you're using platinum silicone, the master must be fully cured. Fabrishare is a network of makers: post your project for free and get quotes within 24–48 hours.
What can you reproduce from a printed master?
The master is printed once and the mould makes copies in materials that can't be printed. Typical cases, by casting material:
| Copies in | Mould | What matters in the master | Watch out for |
|---|---|---|---|
| Casting resin | Silicone | A smooth surface: every mark is copied | Bubbles are dealt with when casting, not in the master |
| Plaster, ceramic plaster or concrete | Silicone or a rigid printed mould | A flat base and slightly angled walls | Large parts are better in FDM, printed in sections |
| Wax and candles | Silicone | Fine detail and no impossible undercuts | The wick needs its hole in the master |
| Soap | Silicone | Strong relief and rounded edges | Very fine detail is lost when demoulding |
| Chocolate and baking | Food-safe silicone | A smooth, sealed master | The printed part never touches the food |
| Clay, modelling paste or silver clay | A stamp or mould printed directly, in resin | Crisp relief, in negative | Sulphur-based clay spoils platinum silicone |
Resin or FDM for the master?
It depends on size and on how smooth the copy needs to be:
Resin: for small, detailed parts
Fine layers and an almost smooth surface: the usual choice for masters of figures, jewellery, model parts, stamps and reliefs. Ask for it sanded and primed if the copy has to be perfect, because silicone reproduces even the mark of a support.
FDM: for large parts
Planters, panels, concrete pieces or masters of 20 cm and up. Layers show more: the maker can sand and prime or seal the part so they don't transfer to the mould. Ask for it in the project, as it's finishing work.
Printing the mould directly
For plaster, concrete, soap or clay, printing the mould (or the stamp) without silicone is sometimes enough. It's rigid: it needs slightly angled walls and no undercuts, and layer lines show on the copy. Not for food: there, you print the master and cast the mould in food-safe silicone.
If the silicone stays tacky, the master wasn't cured
Platinum (addition-cure) silicone may not cure against 3D printing resin that hasn't finished curing: it stays soft or sticky right at the surface of the master. It's a known problem, and it has a fix.
What silicone makers recommend: wash the part well, cure it under UV light for at least 6 hours while turning it so the light reaches everywhere (deep recesses left in shadow cause trouble), seal it with a clear acrylic lacquer or an epoxy coating, and test on a small patch first. Clear resin cures through better than opaque resin. Tin-cure (condensation) silicone is far less prone to this, although the mould has a shorter shelf life.
When you order, say in the project that it's a master for platinum silicone: the maker will deliver it fully cured and, if you ask, sealed.
What a good master looks like
What helps the mould come out right first time, and what usually causes trouble:
Helps
- A smooth surface: fine layers, sanding and primer
- A flat base to glue to the bottom of the mould box
- For rigid moulds, walls angled 1–2° so the copy releases
- A closed part: drain holes filled and sanded
- A mould box printed to size, if you order it at the same time
Causes trouble
- Deep undercuts in a rigid mould: the copy won't come out
- Untreated layer lines: they show on every copy
- Open holes: silicone gets in and the mould tears when the master comes out
- Very thin features that stay stuck in the mould
- Under-cured resin with platinum silicone
How much does a printed master cost?
Size references from the Fabrishare calculator, excluding VAT and shipping: a resin piece about 7.5 cm tall takes about 1.5 hours of machine time and a 20 cm one about 4 hours. Fine sanding, priming or sealing to get it mould-ready may be extra: ask for it in the project and it will appear in the quote.
| Size reference | Technology | Range | Typical |
|---|---|---|---|
| 75 mm bust | Resin | €15 – €40 | €25 |
| 20 cm figure | Resin | €21 – €55 | €34 |
| Small spare part (bracket, clip) | FDM | €6 – €17 | €10 |
| Medium case or cover | FDM | €7 – €19 | €12 |
Large FDM masters and large printed moulds have no ballpark price: they depend on machine hours, whether they're printed in sections and the finish. Each maker quotes once they see the file.
What to tell the maker
- 1
The file, at full size
The STL or STEP of the part exactly as you want the copy. If you don't have one, some makers model or scan it from an existing part.
- 2
What it's for
That it's a master for a mould, what you'll cast the copies in and which silicone you'll use (platinum or tin). That decides resin or FDM, and the curing.
- 3
The finish
Whether you want it sanded, primed or sealed, or you'll sand it yourself. It's what changes the copies most.
- 4
How many masters
One per mould. If you'll produce faster with several moulds at once, order several masters in the same project: it's cheaper than one at a time.
Masters and moulds in the network
One of the 110 requests registered between May and October 2026 was a set of negative stamps for silver clay: a mould printed directly, in resin.
Metal jewellery: another route
To cast in silver or gold you don't need a silicone mould: the piece is printed in castable resin and cast with the lost-wax method.
3D printed jewelleryMould, or print every copy?
If the copy is plastic and you need only a few, printing them all is sometimes better. A mould pays off with materials that can't be printed, or with many copies.
Small batch 3D printingPrototype before the mould
If the part may still change, print a test before making the mould.
Rapid prototypingSmall brands and workshops
Candles, soaps, figures or concrete pieces in batches: masters and repeat orders for your production.
3D printing for businessNo 3D model
From sketches, photos or a part to copy, some makers model or scan it; it's quoted separately.
No STL file?
How to order your master
- 1Post your project for free with the file, the casting material, the silicone you'll use and the finish you want.
- 2Makers in the network send you a quote with price, technology and lead time within 24–48 hours.
- 3You choose, and the maker prints the master and ships it ready for mould-making.
Frequently asked questions
What is a master for a mould?
The original part the mould is taken from. It's covered in silicone, removed, and the cavity left behind is used to cast copies in resin, plaster, wax, soap and other materials. 3D printing it is the quickest route when the part only exists as a file.
Resin or FDM for the master?
Resin for small, detailed parts, as the surface comes out almost smooth; FDM for large parts, sanded or sealed so the layers don't show. A resin piece about 7.5 cm tall costs €15–€40 and a 20 cm one €21–€55, excluding VAT and shipping.
Why won't the silicone cure on my printed part?
It happens with platinum silicone when the resin isn't fully cured: it stays tacky where it touches the master. The fix is to cure the part under UV light for at least 6 hours while turning it, seal it with a clear acrylic lacquer or an epoxy coating, and test on a small patch first. Tin-cure silicone rarely has this problem.
Will the print layers show on the copies?
Yes, if they aren't treated: silicone copies every detail, layer lines and support marks included. In resin they barely show; in FDM the part needs sanding, priming or sealing. Ask for it in the project.
Can the mould itself be printed?
Yes, for plaster, concrete, soap or clay, and as a stamp. It's a rigid mould: it needs walls angled 1–2° and no undercuts, and the copy carries the layer lines. For detailed parts or undercuts, a master and silicone are better.
Does it work for chocolate moulds?
Yes, but the printed part shouldn't touch the food: the gaps between layers trap dirt. You print the master, seal it and cast the mould in food-safe silicone.
Can they make the mould or the copies too?
Fabrishare is for ordering the printing. If you also want the mould or the copies, say so in the project: each maker will tell you in their quote whether they do it and what it costs.
What if I don't have a 3D model?
From dimensioned sketches, photos or a part to copy, some makers model in 3D or scan. The design is quoted separately and shows in the quote.