Please consult the application manual for detailed information on state-of-art application methods and joint design. Please contact your local sales office for specific advice.

Preparation

Clean all joints and glazing pockets, removing all foreign matter and contaminants such as grease, oil, dust, water, frost, surface dirt, old sealants, or glazing compounds and protective coatings.

Application Method

• Install backing material or joint filler, setting blocks, spacer shims, and tapes. Areas adjacent to joints may be masked to ensure neat sealant lines.
• Primer is generally not required on non-porous surfaces. It is recommended that a field test be carried out prior to application. To confirm optimum adhesion on either a porous or non-porous surface, adhesion testing should always be carried out prior to the commencement of any project. Please contact your local sales office for specific advice.
• Apply DOWSIL™ 688 Glazing and Cladding Sealant in a continuous operation using a positive pressure. Tool the sealant with light pressure and spread the sealant against the backing material and joint surfaces before a skin is formed. The applied sealant should be tooled and masking tape should be removed before the sealant has formed a cured skin.

DOWSIL™ 688 Glazing and Cladding Sealant is neither tested nor represented as suitable for medical or pharmaceutical uses.

It should not be used:

• In below-grade applications
• On frost-laden or wet surfaces
• On joints involving excessive abrasion
• On surfaces that are continuously immersed in water
• On building materials that bleed oils, plasticizers or solvents – materials such as impregnated wood, oil-based caulks and certain green or partially vulcanized rubber gaskets and tapes
• To copper or copper containing building materials
• In totally confined joints (the sealant requires atmospheric moisture for cure)
• If the sealant is intended to be painted (paints do not typically adhere to most silicone sealants)
• To surfaces in direct contact with food or other food-grade applications
• To uncured sealant other than DOWSIL™ 688 Glazing and Cladding Sealant. Sealant with different cure chemistry, such as one-part structural sealants, should be fully cured before DOWSIL™ 688 Glazing and Cladding Sealant is applied.