Groundwork · the thing the mould is taken from
A mould is only as good as the master it is cast around. Every blemish, print line and soft edge on your master is reproduced faithfully on every part throughout the life of the tooling. That is where quality is decided.
Four ways to a master
The cheapest master is rarely the cheapest job, because anything left behind by the process still has to be removed by hand.
Printed masters are quick to produce from CAD and work well for complex geometry. However, they arrive with layer lines. On a curved face, those lines can transfer straight through the mould and onto every casting. Printed masters need filling, sanding and sealing, and finishing them is often more work than printing the master itself.
Prototype tooling
If you need genuinely flat faces and sharp arrises, cutting from board, resin or metal can be a strong choice. It gives you the finish that printing can struggle with and needs the least finishing. It costs more up front and does not suit deep undercuts, because the cutter must be able to reach every surface.
CAD and DFM
Sculpted, carved or built up by hand, this is the right approach for organic shapes and decorative work where the eye is the only judge. It is slow, and a damaged piece cannot be repeated exactly. That is why we treat the retained master as the valuable object.
Hand-made moulds
If you already have one, use it. Just bear in mind what you are inheriting: the wear, the flash, the old repair and any shrinkage from the original process. The copy will faithfully reproduce the part you send us, not the drawing it was intended to match. Scanning is the way forward if you need the intended shape instead.
Finishing
Before silicone goes near your master, we prepare it carefully. Layer lines and tool marks are filled and sanded smooth. We check every edge, because even a hairline chip can become a permanent feature. Surfaces are sealed too, so the silicone does not key into a porous face and tear the master apart during release.
Sealing has another important job: it helps protect against cure inhibition. Sulphur in some clays, residues from certain adhesives and some fillers can stop silicone curing where they touch it, leaving a tacky patch that never sets. The solution is to prepare the master properly. Adding catalyst is not.
The right level of finishing depends entirely on what your part is judged on. For a gloss decorative face, the master needs polishing to a gloss because the mould copies the surface it is given. A matt structural part needs no such polish, so paying for one would simply add unnecessary cost.
At this stage, we also sort out the draft, keys and witness edge, along with where the mould will part. These decisions are part of a joint conversation about design for manufacture, rather than something left until the pour.
Repeats
Soft moulds wear out, and that is expected. The key to making sure your fourth mould produces the same part as your first is whether it was cast from the original master or from something that came out of the third mould.
Every time you copy a copy, you lose a little: an edge becomes slightly softer, the mould shrinks by a fraction, or a blemish appears. After three copies, the range no longer matches itself. That is why we keep the master, record the grade and take every replacement mould from the original. It is the foundation of replacement and spare moulds.
Masters are physical objects, so they can be damaged. It is worth agreeing at the start who will hold the master and what will happen if it is dropped. For high-value hand-modelled work, taking a second master from the first while it is still pristine is cheap insurance against losing the geometry entirely.
If the master is no longer available and you only have a used part, that's a reverse engineering job. It's a normal enquiry, and it starts with you sending us the part in a jiffy bag.
To quote it
Choose gloss, satin, matt or textured, and tell us which faces are visible and which are hidden. We'll finish the master to that standard, and no further.
When marking up your part, highlight any lettering, arris or fit face. These features can influence the choice between printing and machining more than the overall shape does.
CAD, a drawing, a sample or a photograph can all give us a starting point. A physical sample usually saves you the most work.
Whether you need a one-off pour, a boxed cast mould, or a hard tool, the right standard depends on the job. A master used to make hard tooling needs to meet a different standard from one used for a single silicone pour. If you're not sure yet, start with the five routes.
At a glance
From idea to finished mould
Swipe to see the whole diagram
Ready to start?
Send us a drawing, a photograph or a sample, and 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