Step 1: Correct Joint Design guidelines:

• Minimum joint width of 6 mm.
• Minimum joint depth of 6 mm.
• For larger joints, the width of the joint should be greater than the sealant depth, the recommended ratio of joint width to depth is 2:1.
• Avoid 3-sided adhesion: Apply backer rod or bond breaker tape in the base of the joint to ensure that the sealant is only bonded to the sides of the joint and is free to move to its full capacity under joint movement.

Step 2 Clean All Joint Surfaces:

For all substrates, surfaces must be completely clean and dry. Remove any loose debris and/or old sealant or any protective films. Use cleaning solvents such as toluene, xylene, methyl ethyl ketone, and banana oil to wipe the surfaces. For non-porous materials such as glass and aluminium alloy materials, first wipe the interface surface with a lint-free, white cloth and solvent to clean any grease or dirt. Then, immediately wipe again with another piece of clean cloth to completely remove any remaining solvent and impurities from the interface. Some materials may require use of a Dow primer to enhance adhesion to the material. Please contact Dow for more information on Dow primer.

Step 3 Install Backing Material:

Use a backer rod (like closed cell polyethylene type or open cell polyurethane foam type) or similar material (like low tack polyethylene tape for shallow joints) in the base of the joint to control sealant depth. Avoid 3-sided adhesion by preventing adhesion to the base of the joint.

Step 4 Mask Adjacent Surfaces with Masking Tape: Masking will ensure a clean, neat appearance and reduce clean up by protecting surrounding areas from excess sealant.

Step 5 Applying Sealant:

• Cut open the tip off the cartridge.
• Cut nozzle at 45° angle to the desired shape and size.
• Screw nozzle onto the cartridge.
• Place cartridge in caulking gun (air-operated or hand-operated caulking guns can be used)
• Apply sealant into the base of the joint so that it completely fills the joint, wetting both sides. (Do not simply lay a bead on the surface as the sealant will not penetrate the joint under its own weight.)

Step 6 Tool Joint and Remove Masking Tape:

• A tool with a convex profile is recommended to keep the sealant within the joint.
• Tool the surface of the joint immediately after sealant application to provide a smooth even finish and ensure that the sealant wets the sides of the joint.
• Tooling should be completed in one continuous stroke before the sealant forms a skin (i.e.: within the working time of 10 minutes). When you seal horizontal joints, take care to tool the sealant such that any liquid (rain water or cleaning solutions) is not collected on top of the sealant.
• Do not use soap or water as tooling aids.
• Remove masking tapes immediately after tooling and before the sealant forms a skin.
• After a skin has formed, do not disturb the joint for 48 hours.
• Avoid contact with various cleaning agents or solvents when the sealant is curing.
• Uncured sealant can best be cleaned from tools using commercial solvents such as xylene, toluene or methyl ethyl ketone. Cured sealant is not soluble and can be trimmed with a blade.

Test it before use. The user is responsible to conduct property test before using to confirm the sealant produces satisfied results. Especially for the surface which is difficult to adhesion and coated substrates, the cohesiveness should be tested. Be careful of the application temperature. When the substrates surface is over than 50°C, it is easy to cause fast-cure or bubbles. When the substrates temperature is lower than 5°C, it is easy to slow-cure. And also, a layer of indiscernible fog may be formed on the surface of substrates, which affects the cohesiveness, so it should be wiped with a piece of dry cloth or heat blow drier. Keep environment well-ventilated and avoid inhaling too much volatile gas generated during cure.

DOWSIL™ Neutral Purpose Silicone Sealant product is not suitable -

• For unventilated places
• For curtain wall glazing
• On surfaces that are continuously immersed in water
• On materials that bleed plasticizers or solvents or release by-products that may inhibit its cure, affect adhesion or discolour the sealant
• On frost-laden or wet surfaces
• 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
• This product is neither tested nor represented as suitable for medical or pharmaceutical uses.