Silicone Primer (Dowsil 1200 OS)

Dowsil 1200 OS Primer is used to improve adhesion and accelerate the adhesion build-up of silicone elastomers to various substrates.This moisture-curing primer is formulated as a diluted solution of reactive materials in low-viscosity siloxane, ensuring optimal adhesion and durable results on a wide range of surfaces. Dowsil is particularly suitable for improving adhesion of silicones to metals. Always perform a test before using the primer.

Features

• Improves adhesion of silicone elastomers and foams to many substrates.
• Provides stonger and more uniform bonds.
• Low VOC content of 76 g/l.
• Formulated for low toxicity.
• Resistant to ozone, ultra-violet radiation and temperature extremes.
• Suitable for weather sealing and structural glazing.

Directions for use

For many substrates, significantly stronger and more uniform bonds can be achieved by first treating the surface with a primer before applying the silicone sealant. For best results, follow the steps below (not applicable to silicone rubber):

1. If necessary, thoroughly clean and degrease the surface with two cloths and a suitable solvent. Allow the surface to dry.

2. Apply a thin layer of DOWSIL 1200 OS Primer with a clean white cloth or brush. In most cases, a thin layer provides the best adhesion. If a white chalky residue after a few minutes of drying, wipe it off with a clean cloth.

3. Allow the primer to air dry for 15 to 90 minutes under normal temperature and humidity conditions (room temperature, approx. 50% RH). As the primer cures upon contact with moisture in the air, lower humidity will require a longer drying time. Determine the optimal drying time for your specific conditions beforehand. Please note: primer that cures for too long will no longer improve adhesion. Therefore, avoid drying times longer than approximately 6 hours under normal conditions.

4. Apply silicone sealant.

Specifications

Contents: 500 ml
Colour: transparent
Viscosity: 1 mPa.s (at 23°C)
Flash point: 27°C
VOC content: 76 g/l
Specific gravity: 0.84 (at 23°C)
Shelf life: 18 months (stored below 25°C in unopened container)