Part of TCI Group · UK design, UK manufacturing capability, since 2019
Hand-made, cast, vacuum cast, compression and injection: five ways to make a silicone mould, each with honest reasons to choose it. What your part needs to do decides the right route, not what we prefer to run.
Where to start
There are many ways to shape silicone, and most belong to somebody else's factory. Five are ours, covering everything from a one-off development mould to a rolling annual programme.
Choosing the right route is not a matter of preference. It comes down to four things: how many parts you need, what you are pouring or pressing into the mould, how much detail needs to survive, and who has to demould it at the end of a shift. Get those four details clear and the route will usually choose itself.
Here is what each route is genuinely good at, and where it stops making sense. If your part sits on a boundary, tell us when you send it over and we will explain which side we think it falls on.
The five routes
The same workshop can give you five different answers. Tooling cost, unit cost and the level of detail you can hold all move together.
Silicone is laid up or poured by hand around a master. This is the cheapest and fastest way to produce a working mould. It works best when the shape is generous, the run is short and the finish does not need to be identical from part to part.
Hand-made moulds
A properly boxed two-part mould is cast around a finished master, with the split line chosen rather than accepted. It is the workhorse for candles, homeware, plaster and resin, and for anything with an undercut worth keeping.
Cast moulds
It uses the same casting discipline, carried out under vacuum so the air is removed before the silicone sets. If you need fine relief, crisp arrises and a surface that needs no making good afterwards, this is the process for you.
Vacuum casting
For moulded silicone components rather than moulds, we use steel tooling and a heated press. The tooling cost is higher, but the cost per part is much lower, with repeatability that hand casting cannot reach.
Compression moulding
Liquid silicone is injected into a hardened production tool. This requires the highest tooling investment, but gives you the lowest unit cost for parts you will be buying for years rather than months.
Injection mouldingRouting
We don't quote from a photograph alone. These are the questions we ask, in order.
It could be wax, plaster, resin, concrete, chocolate or silicone itself. The material affects how easily your part releases, the temperature your mould needs to withstand and whether food-contact paperwork is needed.
Whether you need one development piece, enough for a season, or a repeating annual quantity, the volume and timescale matter.
They are the single biggest factors in deciding whether soft tooling or steel tooling will be the cheaper option over the life of the job.
If your part has fine relief, lettering, thin walls and sharp arrises, it is likely to need vacuum casting or a hard tool. Generous, rounded shapes do not need either.
The person demoulding it matters. A skilled maker will flex a mould that a production operator on a Friday afternoon will tear. That's why wall thickness, hardness and the split line are set around whoever will actually demould it.
We spread the tooling cost across the run and quote a cost per piece. That is the figure that helps you decide whether your job makes sense.
Compare
This is a rough guide, not a quotation. Every column moves once we see the actual part.
| Route | Typical run | Tooling cost | Cost per part | Detail held | Best for |
|---|---|---|---|---|---|
| Hand-made | 1 to 50 | Lowest | Highest | Moderate | Development pieces, generous shapes, short runs |
| Cast | 10 to 500 | Low | Moderate | Good | Candles, homeware, plaster and resin, undercuts |
| Vacuum cast | 10 to 500 | Low to medium | Moderate | Highest of the soft routes | Fine relief, lettering, crisp arrises |
| Compression | 250 upwards | Medium to high | Low | High and repeatable | Moulded silicone components at volume |
| Injection | 1,000 upwards | Highest | Lowest | High and repeatable | Long-term component supply |
Run lengths overlap on purpose, so a 400-piece job can sit in three of these columns. The right choice depends on your part, not simply the number of pieces.
Four questions
If your part locks into the mould, a rigid tool must either split around it, or the mould must flex. That single fact can rule manufacturing routes in or out faster than anything else.
If the smallest detail that matters is finer than a millimetre, the air must be removed under vacuum or forced out under pressure.
If your mould is going into an oven, autoclave or heated line, the process changes the grade you need, not just the shape. For high-temperature work, we specify around the cycle, not the part alone.
If you need the silicone component itself, you're looking at compression or injection. If you want to cast something else in the silicone, you're looking at the first three processes.
Go deeper
Each route has its own page, with the detail you need to choose confidently: what it suits, what it does not, what we need from you to quote it, and the practical limits we'll explain before you commit.
If you already know which route you need, start there. If not, send us your part and we will tell you which route it needs and why.
Route pages
Laid up or poured by hand around a master, this is the fastest route to a working mould.
Hand-made mouldsSteel tooling and a heated press for moulded silicone components.
Compression mouldsGroundwork
Before we can cut a mould, most jobs need some preparation. This is chargeable work in its own right, and it often makes the mould possible.
We review your geometry for draft, split line, wall thickness and any features that could make the mould more difficult to produce.
CAD and DFMIf you do not have a master to cast from, we can make one in plaster, resin or printed polymer.
Master patternsWhen the original tooling is long gone, we can work backwards from a sample to recreate the drawing and mould.
Reverse engineeringWe choose the hardness to suit who will demould it and how often, rather than simply following a catalogue.
Shore hardnessChecking
Every mould and every first-off part is checked against its intended specification. We measure the dimensions that matter, assess the surface where it matters, and physically check that the part demoulds without a fight.
If a job has paperwork attached, we record the material and specification against your order. That means the grade you approve is the grade you continue to receive.
If something is out of specification, we will tell you before it ships. That is better for everyone than discovering the issue on your line.
Questions
Yes, and it's a common path. Many jobs start with a cast development mould, then move to compression or injection once the shape is settled and quantities justify hard tooling. Your design work carries over, which is why it's worth getting the CAD stage right the first time.
No. A sample, a photograph with a rule in shot, or a hand sketch is enough to start a sensible conversation. If we need geometry you do not have, scanning or reverse engineering can produce it. We will tell you which approach your part needs.
If you're choosing among soft routes, vacuum casting draws the air out before the silicone sets, rather than requiring it to be chased afterwards. For repeatable fine detail at volume, a hard tool used for compression or injection will hold that detail more consistently.
Not quite. Hardness is a trade-off. A harder mould holds its shape and lasts longer, but it will not release an undercut and can be harder on the person demoulding it all day. We choose the right hardness for the part and the person, not simply a number.
Yes. For food-contact work, the grade and paperwork matter just as much as the shape. Our food division manages this work, so the declarations are kept in one place.
That usually suggests one of two options: a flexible route, or a hard tool that splits around the feature. It is exactly the kind of detail to raise at sketch stage. Designing the split line early is far cheaper than discovering it after tooling.
One group, four specialisms
Shared engineering, one workshop and four specialisms give you access to the tooling knowledge behind a precast yard, even if you are a chandler with one product.
At a glance
Which route suits your quantity
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From idea to finished mould
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Ready to start?
Send us a drawing, photograph or sample. We'll come back to you with a mould strategy, a material recommendation and a price.
Real people, a real workshop
No call centre and no middlemen. When you contact TCI Mouldings, you speak to the team who design, build and check your mould.
Thomas LaneManaging Director
George PrestonDesign & Project Manager
Kelly BallingerHead of Partnerships
Jim AndertonProduction Manager
TheodoreEmployee Welfare