This generates the printed housing, the rigid box you pour liquid silicone into around your master. It does not generate the silicone mold itself, because that is a physical object you cast. The housing is the tooling; the silicone is the result.
Once the silicone cures you peel the housing off, and the flexible block that comes out is your reusable mold. That flexibility is the whole point: it releases shapes a rigid printed mold physically cannot.
| Use silicone when | Print the mold directly when |
|---|---|
| The master has undercuts | Every surface draws cleanly in one direction |
| You need fine surface detail reproduced | Detail is coarse, or you will finish the cast anyway |
| You will cast the same thing many times | It is a one-off |
| The cast material would stick or attack a printed mold | Plaster, concrete or wax, which release fine from PETG |
| You want no layer lines on the cast | Layer lines do not matter, or you will sand |
The full version of this decision, with costs, is in silicone vs direct-print molds.
| Setting | Use | Why |
|---|---|---|
| Walls | 3 to 4 perimeters | The housing has to hold a column of liquid without bowing |
| Infill | 15 to 20% | Perimeters carry the load; infill just stops flex |
| Layer height | 0.2 mm | The housing's surface finish does not reach the cast |
| Material | PLA is fine | Silicone cures at room temperature, so there is no heat to resist |
| Seams | Tape or hot glue on the outside | Uncured silicone finds every gap, and a leak wastes the whole pour |
Cure inhibition, and it is the single most common silicone failure. Something on the master poisoned the platinum catalyst, and resin-printed masters are the usual culprit. The full diagnosis and fix is in silicone mold not curing.
Uncured silicone is thinner than people expect and finds every seam. Seal the outside of every joint with tape or hot glue before pouring, and stand the housing in a tray so a leak costs you silicone rather than your table.
Silicone is denser than PLA. Glue the master to the base with a dab of hot glue or double-sided tape before pouring, or weight it.
Air whipped in while mixing, or poured too fast. Stir slowly with the stick below the surface, then pour a thin stream from a height. A pressure pot or vacuum chamber removes the rest, but technique gets you most of the way.
A box mold fills the whole volume around the master, and silicone is the expensive part of this hobby. Adaptive silicone follows the master's actual silhouette instead of boxing it, which cuts the volume substantially on anything that is not roughly cuboid.