Application Methods:

It is essential that a uniform, thin coating of the selected primer is applied and allowed to dry completely before bringing it into contact with the silicone elastomer system.

All silicone primers are supplied as solutions in a wide variety of organic solvents. Some of these solvents present a greater hazard to the user than others. Full details of the solvents and any other potentially hazardous components are given in the individual product Safety Data Sheets, which are available on request.

NB: Always handle primers in well-ventilated areas away from any potential sources of ignition.

• Select the primer of choice or contact CHT for advice on the best primer for a specific application.
• Degrease all surfaces to which the primer and silicone rubber are to be applied. Care should be taken to avoid high boiling point solvent fractions, which often leave undesirable residues.
• Allow the surface to dry or wipe dry with a clean, felt-free rag.
• If applying by brush, apply sparingly and clean brushes in a suitable solvent after use.
• Apply primer to the degreased dry surface to be bonded using single light applications.
• If possible, avoid multiple applications - a thin uniform film of primer is more effective.
• After sufficient surface coverage has been achieved, close the primer container.
• Leave primed articles to dry and cure for between 20 and 60 minutes depending on ambient temperature conditions (the use of elevated temperatures is not recommended). See product data for details.
• If using a one-component silicone sealant, apply it to one primed surface and immediately bring the other primed (or un-primed if desired) surface into contact. Apply gentle pressure to attain close contact, whilst leaving sufficient sealant (normally a minimum of 1mm) to produce a good joint.
• If, for example, adhesion between two substrates employs a 2-part silicone rubber, catalyse and degas the chosen rubber during the primer drying cycle and then pour the rubber in the normal manner.