Sikaflex® HY 35

• ASTM C 920, Type S, Grade NS, Class 35, Use NT, M, A, and O**
• Federal Specification TT-S-001543A, Type II, Class A, Type Nonsag
• Federal Specification TT-S-00230C, Type II, Class A
• Corps of Engineers CRD-C-541, Type II, Class A

** Refer to substrates in Uses.

Sikaflex® HY 35 is a formulation based on hybrid technology.

18 months when properly stored

Store in original, unopened containers in a cool, dry area. Protect unopened containers from heat and direct sunshine. Storing at elevated temperatures will reduce shelf life.

*Sikaflex® HY 35is not recommended for application on glass

Concrete primed with Sika® Primer-179 for water immersion as indicated in ASTM C 920.
Test results are averages obtained under laboratory conditions. Reasonable variations can be expected.

None

-40 to 185°F (-40 to 85°C)

The cure of Sikaflex® HY 35 varies with temperature and humidity. The following times assume 75 °F (24 °C), 50% relative humidity, and a joint 1/2" (13 mm) in width by 1⁄4" (6 mm) in depth.

Meters per Liter
(One liter equals approximately 3.33 cartridges)

• In cold weather, store the container at room temperature for at least 24 hours before use.
• Do not allow uncured Sikaflex® HY 35 to come into contact with alcohol-based materials or solvents.
• Sikaflex® HY 35 should not be applied adjacent to other uncured sealants and certain petroleum-based products.
• Sikaflex® HY 35 can adhere to other residual sealants in restoration applications. For best results, always clean the joint as advised in the Surface Preparation section of this data guide. A product field adhesion test for Sikaflex® HY 35 within the specific application is always recommended to confirm the adhesion and suitability of the application.
• Sikaflex® HY 35 should not be used for continuous immersion in water. Contact Technical Services for recommendations.
• Do not use Sika® Primer-179 on nonporous surfaces such as aluminum, steel, vinyl, or Kynar 500-based paints. Use Sika® Primer-173 on coated metals when testing dictates.
• Lower temperatures and humidity will extend curing times.
• Sikaflex® HY 35 can be painted over after a thin film or skin forms on the surface.
• Pursuant to accepted industry standards and practices, using rigid paints and/or coatings over flexible sealants can result in a loss of adhesion of the applied paint and/or coating, due to the potential movement of the sealant. However, should painting and/or coating be desired it is required that the applicator of the paint and/or coating conduct on-site testing to determine compatibility and adhesion.
• Proper application is the responsibility of the user. Field visits by Sika personnel are for the purpose of making technical recommendations only and not for supervising or providing quality control on the jobsite.

Substrates must be structurally sound, fully cured, dry, and clean. Substrates should be free of the following: dirt, moisture, loose particles, oil, grease, asphalt, tar, paint, wax, rust, waterproofing or curing and parting compounds, membrane materials, and sealant residue.

Concrete, Stone, And Other Masonry

Clean by grinding, sandblasting, or wire brushing to expose a sound surface free of contamination and laitance.

Metal

1. Remove scale, rust, and loose coatings from metal to expose a bright surface.
2. Test all coatings on metal that cannot be removed to verify the adhesion of sealant or to determine an appropriate primer.

Wood

1. New and weathered wood must be clean, dry, and sound.
2. Scrape away loose paint to bare wood.
3. Test all coatings on wood that cannot be removed to verify the adhesion of sealant or to determine an appropriate primer.
4. For freshly treated wood; allow six months for weathering.

Priming

• Sikaflex® HY 35 is considered a non-priming sealant, but special circumstances or substrates may require a primer.
• Porous materials subject to intermittent water immersion require priming. Use Sika® Primer-179.
• Certain architectural metal finishes may require priming with Sika® Primer-173.
• It is the user’s responsibility to check the adhesion of the cured sealant on typical test joints at the project site before and during application. Refer to the technical data guides for Sika® Primer-179 and Sika® Primer-173.
• For green concrete applications, Sika® Primer-173 must be used.

• Apply primer full strength with a brush or clean cloth. A light, uniform coating is sufficient for most surfaces. Very porous surfaces may require a second coat of Sika® Primer-179; however, do not over-apply.
• Allow the primer to dry before applying Sikaflex® HY 35. Depending on temperature and humidity, the primer will be tack-free in 15–30 minutes. Priming and sealing must be done on the same workday

Joint Preparation

1. The product may be used in sealant joints designed in accordance with SWR Institute’s Sealants - The Professional’s Guide.
2. In optimum conditions, the depth of the sealant should be 1/2 the width of the joint. The sealant joint depth (measured at the center) should always fall between the maximum depth of ½" and the minimum depth ¼". Refer to Joint width section.
3. In deep joints, control the sealant depth by installing Closed-Cell Backer-Rod or Soft-Cell Backer-Rod. Where the joint depth does not permit the use of a backer rod, use a bond breaker (polyethylene strip) to prevent three-sided adhesion.
4. To maintain the recommended sealant depth, install a backer rod by compressing and rolling it into the joint channel without stretching it lengthwise. Closed-Cell Backer Rod should be about 1⁄8" larger in diameter than the width of the joint to allow for compression. Soft-Cell Backer Rod should be approximately 25% larger in diameter than the joint width. Because the sealant does not adhere to the backer rod, no separate bond breaker is required. Do not prime or puncture the backer rod.

Application

1. Sikaflex® HY 35 comes ready to use. Apply using a professional-grade caulking gun. Do not open cartridges, sausages, or pails until preparatory work has been completed. NOTE: Sikaflex® HY 35 is not a structural sealant.
2. Fill joints from the deepest point to the surface by holding an appropriately sized nozzle against the back of the joint.
3. Dry tooling is recommended. Proper tooling results in the correct bead shape, neat joints, and optimal adhesion.
4. Best practices dictate that all caulking and sealing be done when temperatures are above 40 °F (4 °C) to avoid application to moisture-laden surfaces. Moisture on substrates will adversely affect adhesion. Application may proceed as low as 20°F (-6°C) if there is certainty that substrates are completely dry, free of frost, and clean as described under Surface Preparation.

1. Immediately after use, clean equipment with SikaSwell®-990 or xylene. Use proper precautions when handling solvents.
2. Remove cured sealant by cutting with a sharp-edged tool.
3. Remove thin films by abrading.