Why Wacker’s ELASTOSIL RT silicone rubber quietly powers tough industrial jobs

Reviewed: ad hoc news B2B & Pro desk. Edited and checked on 2026-06-20, 13:53. Details in the imprint.

ELASTOSIL RT silicone rubber from Wacker Chemie looks unspectacular at first glance - two buckets, a slightly viscous liquid, a separate curing agent. Mix them, and a few minutes later a flexible, heat-resistant skin appears that toolmakers and engineers swear by.

What ELASTOSIL RT is built for

ELASTOSIL RT belongs to Wacker’s room-temperature-curing silicone rubber portfolio, typically supplied as a two-part system that crosslinks after mixing. In everyday factory life, that means a pot life of minutes to hours and then a steady, predictable cure to an elastic solid.

Depending on grade, processors get Shore A hardness from very soft to clearly firm, so the same family can handle delicate mold-making for design studios and robust seals in industrial equipment. Many variants are formulated to resist temperatures well above 150 degrees Celsius and remain flexible in the cold.

How it behaves on the workbench

On the bench, ELASTOSIL RT usually pours like a thick syrup. That flow is crucial - it creeps into fine grooves of a master model, around fragile electronic parts, or into tight seal geometries where conventional rubber sheets would never fit without stress and warping.

After curing, the silicone surface feels slightly silky, not sticky, and can be peeled off sharp edges without tearing if the right grade and mixing ratio are used. Toolmakers appreciate that dimension changes are low, so the reproduced parts stay close to the original size.

Typical use cases from molds to electronics

One classic field for ELASTOSIL RT is mold-making in prototype shops and art foundries, where complex shapes must be replicated many times. The material captures textures down to hairline scratches and holds up over repeated demolding cycles.

Another important use is encapsulating and potting electronic assemblies that need protection against moisture, vibration, or dust. The cured silicone forms a flexible barrier that still allows heat to escape better than many rigid potting compounds.

Processing details that matter in practice

For production managers, the ability to tune catalyst content and mixing ratio is key. With that, the same ELASTOSIL RT chemistry can be optimized for fast demolding in a serial process or slower curing for complex, hand-filled molds where working time is precious.

Many grades are formulated for easy degassing under vacuum, which reduces bubbles and gives clear, clean surfaces in transparent or pigmented parts. That is especially relevant when optical impression or reliable sealing surfaces decide whether a batch is scrap or shippable product.

Where the limits show up

Despite its strengths, ELASTOSIL RT is not perfect for everything. For very high mechanical loads, hard impacts, or sharp cuts, classic thermoplastic elastomers or even metals still have advantages that silicone cannot match.

In addition, silicone rubbers like ELASTOSIL RT can be more expensive per kilogram than commodity polyurethane or epoxy systems. For high-volume, cost-sensitive parts, processors therefore weigh carefully where the extra performance justifies the material budget.

Company context and share listing

For Wacker Chemie, specialty silicones such as ELASTOSIL RT underline its positioning as a solutions and materials supplier to industrial customers rather than a pure bulk-chemicals player. The segment benefits from long-term customer relationships and high switching barriers once processes are qualified.

Shares of Wacker Chemie (DE000WCH8881) trade on Xetra in euros.

This article was AI-assisted and editorially reviewed. Product information without guarantee; prices and availability may change at short notice. No investment advice, no buy or sell recommendation. Stock-market transactions involve risks up to total loss.