WACKER ELASTOSIL AUX G3243 20kg – Primer, Adhesion Promoter for Improving Silicone Adhesion to Surfaces

ELASTOSIL® AUX G 3243 is a solvent-based mixture of siloxanes and reactive silanes that serves as a universal primer improving the adhesion of silicone rubbers to a wide variety of substrates. The product forms a thin, rigid silicone resin layer on the surface of metal, ceramics, glass or polymeric materials which, after evaporation of the solvent and contact with atmospheric humidity, provides an excellent, durable bond with subsequently vulcanized silicone elastomers of the ELASTOSIL® R type (HCR/HTV, peroxide-cured). The primer is characterized by a yellow colour, a density of approximately 0.85 g/cm³, a solids content of 23 % and a kinematic viscosity of around 550 mm²/s, and contains a mixture of Isopar E and xylene as solvents. Thanks to this it can be applied by various methods – coating, dipping, brushing or spraying – both undiluted and after further dilution with organic solvents (e.g. white spirit or Isopar E) in a ratio of up to 1:10. The best results are obtained with a very thin layer of 1–10 µm thickness (corresponding to a coating weight of 5–50 g/m²), which is why the substrate should be thoroughly cleaned before application and the primer itself carefully mixed. After application the solvent evaporates at room temperature and moderate atmospheric humidity for at least two hours, forming a consistent, well-adhering film; the silicone should be applied as soon as possible afterwards, but no later than within two days. In some cases adhesion can be further improved by heating the primed substrate to 100–150 °C for up to one hour. The primer is particularly effective on surfaces with varied structure, while very smooth substrates are recommended to be roughened beforehand. ELASTOSIL AUX G3243 is a general-purpose product that is sensitive to humidity; therefore after use it should be stored in a tightly sealed container and thoroughly stirred or shaken before each application.