Sika® Duoflex NS

• Meets ASTM C920, Type M, Grade NS, Class 25, Use T₂ (requiring appropriate total recessed joint design considerations), NT, I, A, G, M and O.
• Compliant with NSF/ANSI 61 "Drinking Water System Components - Health Effects" for potable water contact after full cure (reference: IAPMO R&T File No. K-12483).

12 months from date of production if stored properly in original, unopened and undamaged, sealed packaging.

Store in cool, dry, well ventilated conditions, out of direct sunlight at temperatures between 4 °C and 35 °C (40 °F and 95 °F).

Excellent

Refer to the "Chemical Resistance Chart for Sika^® Duoflex NS / SL''.

Very good

-40 °C to +77 °C (-40 °F to +170 °F) when fully cured

Very good

Always mix entire units. Do not batch down.

Precondition Components A and B to temperatures between 18 °C and 24 °C (65 °F and 75 °F) before mixing and application. Preconditioning components to approximately 21 °C (70 °F) before mixing are strongly recommended when working at the far ends of the application temperature range. Move preconditioned units of Sika® Duoflex NS to work areas just prior to mixing and installation.

4 °C to 38 °C (40 °F to 100 °F) 

4 °C to 38 °C (40 °F to 100 °F) 

Beware of surface condensation To avoid dew point conditions during application, substrate temperature must be at least 3 °C (5 °F) above measured dew point temperature.

 Linear metre per litre (Linear feet per liter)

All joint surfaces must be clean, structurally sound, dry, free of contaminants, dust, and frost. Interior joint surfaces must be free of oils, grease, paints, coatings, sealers, curing compound residues, rust and any other foreign matter that might prevent good adhesion. Ideally substrate preparation should be accomplished by mechanical means, such as sandblasting, abrasive grinding, etc. Mask off and protect any adjacent surfaces (edges of joint) that should not be in contact with Sika® Duoflex NS. Closed cell backer rod or bond breaker tape must be installed at the bottom or base of the joint prior to sealant installation to prevent three sided adhesion. Closed cell backer rod diameter should be slightly larger than actual width of joint to provide a friction fit and adequate sealant support.

Joint Design 

Proper joint design for moving joints is 2:1 width to depth ratio (typical), with a recommended 6 mm (1/4 in) minimum and 13 mm (1/2 in) maximum depth of sealant. For nonmoving joints, the width to depth ratio can vary. Contact Sika Canada Technical Service for unusual joint configurations.

Priming

For maximum adhesion or when the fully cured sealant will be placed into Immersion service applications, the use of Sika^® Duoflex Primer-5050 is necessary. Sika® Duoflex NS should completely cover primed surfaces. Contact Sika Canada Technical Service if unsure whether use of the primer is necessary. A uniform, glossy sheen appearance typically indicates adequate priming. Some surfaces, such as porous concrete, may require two (2) coats of Sika® Duoflex Primer-5050. Primer must be tack-free (dry to the touch) before applying sealant. Sealant must be applied same day as primer. Primed surfaces that have not received sealant and left overnight should be re-primed.

Place entire contents of Component B into pail of Component A and mix at low speed (100–300 rpm) using rotary drill fitted with an appropriate mixing paddle. Mix for at least five (5) minutes to achieve a uniform colour, appearance and consistency. Scrape down sides of pail periodically during the mixing procedure. Avoid air entrapment during mixing.

Remark: Mixed material must be used within the published pot life. Do not attempt to thin or use material that has already started to harden and cure. The individual components of the product are formulated, manufactured and shipped to be used together.

Cold Conditions Mixing: When mixing material at temperatures < 10 °C (50 °F), do not to force the mixing paddle to the bottom of the pail. After adding Component B to Component A, mix the top 1/2 to 3/4 of the pail's contents during the first minute of mixing. After scraping down the sides of the pail, mix again for another minute. The sealant mixing paddle should reach the bottom of the pail between the first and second minute of mixing. Scrape down the sides of the pail a second time and then mix for an additional 2–3 minutes until sealant components are well blended to a uniform colour, appearance and consistency.

Uncured material can be removed from surfaces with an approved solvent (e.g. Acetone, MEK or Xylene). Equipment should be cleaned immediately after use. Strictly follow solvent manufacturer's warnings and instructions for use. Cured material can only be removed from surfaces by mechanical means.