Dow Corning 736 Heat Resistant Sealant

• Sealing and encapsulating heating elements in appliances
• Aerospace gasketing
• Moving oven belts
• Industrial ovens
• Bag filters on smoke stacks
• Other critical bonding, sealing, potting, encapsulating and protective coatings where parts must perform at high temperatures

When fully cured and washed, Dow Corning 736 Heat Resistant Sealant complies with FDA Regulation 21 CFR 177.2600, subject to end-use compliance with any applicable total extractives limitations, and for incidental food contact use in official establishments operating under the Federal Meat and Poultry Products Inspection Program. Listed by the National Sanitation Foundation under Standard 51 for direct contact with food. Listed by Underwriters Laboratories. Designed to meet the requirements of MIL-A-46106A.

• Application

  Dow Corning 736 Heat Resistant Sealant is supplied ready to use. Under pressure, it flows readily from its container. The paste-like consistency makes it easy to work; a spatula or wooden paddle can be used for tooling the surface.

• Tack-Free Time

  The cure progresses inward from the surface when exposed to humidified air. At 77°F (25°C) and 50 percent relative humidity, the sealant forms a tack-free skin within 17 minutes. Tooling is not practical after the skin begins forming and should be completed within five minutes after application – even though this may require alternate periods of applying and tooling. If masking tape is used to mark off an area, it should be removed immediately after tooling.

• Cure Time

  Cure time is affected by relative humidity, degree of confinement and cross-sectional thickness of the sealant. Sections up to 3-mm [1/8-inch] thick become rubbery solids in about 24 hours at 25°C (77°F) and 50 percent relative humidity. Less moisture content reduces the time required slightly. In 24 hours, sections up to 3-mm [1/8-inch] thick cure to a rubber.

• Confined Cure:

  In applications where Dow Corning 736 Heat Resistant Sealant may be partially or totally confined during cure, the time required for proper cure is generally lengthened by the degree of confinement. It is possible, with absolute confinement, that cure will not be completed. Metal-to-metal bonds should not overlap more than one inch. Every application involving confinement during cure should be thoroughly tested before use. Curing time increases with the thickness of the sealant.

  NOTE: The odor given off during cure is due to the liberation of acetic acid. This odor disappears as the cure progresses and is not detectable after the cure is complete.

• Bonding
  1. Thoroughly clean and degrease metal and plastic surfaces using Dow Corning® brand OS (Ozone Safe) Fluids or another suitable solvent. Rubber surfaces should be roughened with sandpaper, then wiped with Dow Corning OS Fluids or another suitable solvent. Follow all precautions given on the solvent container label.
  2. For stronger, more uniform bonds, apply a thin film of Dow Corning® 1200 Prime Coat or Dow Corning® P5200 Adhesion Promoter to all surfaces except rubber and silicone rubber. Allow to air-dry for 30 to 45 minutes at room temperature. (Full instructions are provided with the prime coat.)

     Note: Dow Corning 1200 Prime Coat or Dow Corning P5200 Adhesion Promoter are flammable and are not suitable for use in food contact applications. Keep away from heat, sparks and open flames. Use only with adequate ventilation.

  3. Apply Dow Corning 736 Heat Resistant Sealant to the prepared surface in a uniform thickness. In those cases where the sealant is to be used between two surfaces, put the second surface in place, using enough pressure to displace the air but not the sealant.
  4. Let the unit stand undisturbed at room temperature until cured.

• Sealing

  Using Dow Corning 736 Heat Resistant Sealant in sealing applications follows approximately the same step-by-step procedures as outlined for bonding applications. After preparing the surfaces and priming where required, the sealant is applied by forcing it into the joint or seam to obtain full contact between the sealant and the surface.

NOT RECOMMENDED FOR

• Continuous underwater immersion where adhesion or structural bonding is required
• Use on concrete, brick, mortar or other masonry surfaces
• Use on surfaces to be painted; paints do not adhere well to sealant (paint before applying sealant)
• Use on materials such as impregnated woods or oil-based caulks that bleed oils
• Use in totally confined areas; atmospheric moisture is required for cure
• Use on Teflon®1-coated materials, polyethylene, polypropylene or methylmethacrylate (Plexiglas®2); sealant will not adhere well
• Use on or near sensitive metals such as copper, brass, zinc, carbon steel, galvanized iron or magnesium; these metals may be corroded, especially in confined cure conditions, due to the acetic acid released during the cure
• Use on some plastics; may cause stress cracks; test before use