Silicone, and why it behaves differently

Cure inhibition

Some silicones will not cure where they contact particular materials: sulfur-containing clays, latex, certain adhesives and some uncured resins. The result is a permanently sticky layer exactly at the surface that mattered, with the bulk cured normally.

Which makes a test patch standard practice

Before pouring expensive silicone over a master you spent hours on, cure a small amount against the same material. It costs minutes and it is the only reliable way to find an inhibition problem before it ruins both the mold and the master.

Two silicone systems, and they are not alike

Tin-cure and platinum-cure differ in cost, in how long the mold lasts and in how fussy they are: platinum systems give longer mold life and are far more sensitive to inhibition. Choosing between them is a real decision rather than a matter of brand.

Silicone is much less of an exposure problem

It is not the sensitizer epoxy is, which leads people to handle it casually. The catalyst component still deserves respect and the SDS still applies, and the honest summary is that the risk is lower rather than absent.

Molds wear out

Every demold degrades the surface slightly and a mold has a usable life in pulls. For production that is a consumable with a cost per piece, and tracking how many pulls a mold has done is what stops a slowly degrading mold quietly ruining a run.

It is thick, which is a container problem

Uncured silicone is viscous and does not pour out of a narrow neck. For this material a wide mouth is not a convenience, and the residue left in a container is real money.

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