DOWSIL™ 1200 OS Primer
Primer for silicone adhesives and sealants
An air-drying primer supplied as a dilute solution of moisture-reactive materials in volatile siloxane and is used to improve both the quality and rate of room temperature adhesion of vulcanizing silicone sealants to a variety of commonly used non-porous substrates.
- Battery pack, plates and assemblies, components, connectors, engine systems, housings
- DOWSIL™ 1200 OS Primer improves the bond/adhesion of RTV and thermosetting silicones to many materials:
- Engineering plastics
Features and Benefits
- Improves the adhesion of silicone sealants to many substrates
- Useful for both moisture-curing RTV silicones and thermosetting silicones
- Provides more uniform and stronger bonds
- Complies with South Coast and Bay Area Air Quality Management Regulations for architectural waterproofing subfloors
- Low VOC (Volatile Organic Compounds) level of 76 g/l Meets many international regulations including the European Union
- Formulated for low toxicity
- The OS solvent used does not deplete the ozone layer. Labeling = ozone safe
- The primer is suitable for weather sealing and structural glazing applications
- Suitable for most metals, glass, ceramics, masonry, wood, fabrics and some plastics (including FR-4)
|Marble, Metal, Ceramics, Wood, Plastics
|Flash point, closed cup
|Volatile organic content
|Specific gravity at 23°C (73.4°F)
|Viscosity at 23°C (73.4°F) mPa.s
For many surfaces, much stronger and more uniform bonds are achieved by pre-priming them prior to applying the silicone sealant. For best results, follow the steps below on all surfaces except silicone rubber.
- If necessary, thoroughly clean and degrease the surface with 2 cloths and a suitable solvent. Leave the surface to dry.
- Apply a thin layer of DOWSIL 1200 OS Primer with a clean white cloth or brush. In most cases, a thin layer of primer will provide the best adhesion. If you notice a white chalky residue after a few minutes of drying, wipe it off with a clean cloth.
- Under normal temperature and humidity conditions (room temperature, 50% RH), allow the primer to air dry for 15 to 90 minutes. Because the primer cures on contact with moisture from the air, low humidity requires a longer drying time. The optimal drying time for a particular area should be determined prior to use. A primer that has been left to hard cure will no longer increase adhesion. Drying longer than 6 hours at normal temperature and humidity should generally be avoided.
- Apply silicone sealant.
- Note: Always use a separate container when applying with a brush. To avoid contamination and product deactivation, do not mix used materials into a fresh or unused primer can.