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Sikaflex NP 1 (Formerly MasterSeal NP 1)

Sikaflex NP 1 (Formerly MasterSeal NP 1)

6.49

MasterSeal NP1 is a one-component, high-performance, non-priming, gun-grade, elastomeric polyurethane sealant. It requires no mixing and typically requires no priming to bond to many materials, including concrete and masonry.

  • Weather resistant for long-lasting weather tight seals
  • Joint movement capability ±35% provides excellent flexibility
  • Compatible with non-rigid coatings and can be painted

Available in 10.1oz cartridges and 20oz sausages. More colors options available.

Availability: Out of Stock

SKU: 20667

Key Features

One-Component

No mixing required, reducing labor costs and simplifying application.

Joint Movement Capability

±35% flexibility for weathertight performance, even on moving joints.

Weather Resistant

Long-lasting protection against weather and harsh environmental conditions.

No Primer Required

Bonds to most construction materials without the need for priming.

Water Immersion

Documented performance for areas exposed to water.

Available in 12 Colors

Choose from a variety of colors to match common substrates and finishes.

Superior Performance

MasterSeal NP 1 (Sikaflex NP 1) is designed for both above and below grade applications and performs exceptionally well in areas subjected to water immersion, movement, and temperature variations.

Whether for roofing, expansion joints, or store front assemblies, MasterSeal NP1 delivers unmatched durability and ease of use.

Outperforming the Competition

MasterSeal NP 1 is designed for ease of application, making it a top choice for both DIYers and professionals looking to speed up their projects. Its wide temperature range ensures it performs well in any climate, contributing to long-lasting durability. Tested for both fire and water resistance, it’s tough enough to withstand immersion and harsh environments. Additionally, it bonds to green concrete just 72 hours after pouring, helping save valuable time on job sites. Flexible and versatile, it can also be painted, making it compatible with non-rigid coatings for a seamless finish.

Recommended Uses

  • Expansion joints
  • Precast units
  • Window frames
  • Roofing and fascia
  • Parapets
  • Panel walls
  • Vinyl siding
  • Storefront assemblies

Frequently Asked Questions

Can MasterSeal NP1 be used in areas exposed to water?

Yes, MasterSeal NP 1 performs exceptionally well in areas of water immersion, making it ideal for joints exposed to moisture and even some submerged environments.

Does it require a primer?

No primer is required for most materials, reducing installation costs. However, for certain substrates like galvanized steel or in green concrete applications, a primer such as MasterSeal P 173 is recommended.

Are Sikaflex NP 1 and MasterSeal NP 1 the same product?

Yes! Sika purchased Master Builders in May of 2023. While Master Builder products will remain the same high-quality you’re use to, their names will change over time.

Installation Tips

To ensure the best performance of MasterSeal NP 1, consider the following best practices:

  • Do not allow uncured MasterSeal NP 1 (Sikaflex NP 1) to come into contact with alcohol-based materials or solvents.
  • Protect from direct sunlight and heat before application.
  • For areas subject to continuous water immersion, allow for a 21-day cure time at 70°F (23°C) and 50% relative humidity.
  • Always use a primer for certain substrates like galvanized steel or Kynar 500 coatings. We recommend MasterSeal P 173 for priming.
  • Avoid application on treated wood until it has weathered for at least six months.

Packaging Options

  • Cartridges: 300 ml (10.1 fl oz)
  • ProPaks: 590 ml (20 fl oz) ProPaks

Shelf Life

  • 1 year when properly stored in unopened containers. Keep away from heat and direct sunlight.

VOC Content

  • 35g/L, compliant in all 50 states.

Step-by-Step Guide to Using MasterSeal NP 1 (Sikaflex NP 1)

Surface Preparation

To begin, ensure the substrate is structurally sound, clean, and dry. Remove all contaminants such as dirt, grease, oil, old paint, or sealant residue. For specific materials:

  • Concrete or Masonry: Clean the surface using grinding, sandblasting, or wire brushing to remove contaminants.
  • Wood: Scrape away loose paint to expose bare wood and test any coatings to ensure proper adhesion.
  • Metal: Remove rust, scale, and loose coatings to expose a bright, clean surface.

Joint Design and Depth Control

When designing the joint, follow the guidelines established by the SWR Institute. The sealant depth should be 50% of the joint width, with a minimum depth of ¼ inch and a maximum of ½ inch. For deeper joints, insert a backer rod to control the sealant depth. Compress and roll the backer rod into the joint channel without stretching it, ensuring it fits snugly. If the joint is too shallow for a backer rod, use bond breaker tape to prevent three-point adhesion.

Priming (If Necessary)

Sikaflex NP 1 generally does not require primer; however, special conditions may necessitate its use. For applications involving immersion or green concrete, apply Sikaflex Primer-173. Use a brush or clean cloth to apply the primer in a light, uniform coating. Allow the primer to dry for 15 to 120 minutes, depending on temperature and humidity, before applying the sealant. Always test the adhesion of the primer and sealant on-site to ensure compatibility.

Sealant Application

To apply Sikaflex NP 1, cut the nozzle tip of the cartridge to the desired bead size. Use a caulking gun to dispense the sealant in a continuous motion, filling the joint completely. After application, tool the sealant with a spatula or similar device to smooth the surface, ensure proper contact with the joint edges, and remove air pockets. Tooling should be completed before the sealant begins to form a skin.

Curing and Clean-Up

Allow Sikaflex NP 1 to cure fully before exposing it to water or movement. Curing time will vary based on environmental conditions such as temperature and humidity. Clean tools and any accidental spills immediately using a suitable solvent, as specified in the product datasheet.

Additional Tips for Best Results

For optimal application, use Sikaflex NP 1 within a temperature range of -40°F to 180°F (-40°C to 82°C). Store the product in its original, unopened container away from direct sunlight and elevated temperatures to maintain its shelf life.

Joint Width and Sealant Depth

Joint Width Inches (mm)Sealant Depth at Midpoint Inches (mm)
1/4 - 1/2 (6-13mm)1/4 (6mm)
1/2 - 3/4 (13-19mm)1/4 - 3/8 (6-10mm)
3/4 - 1 (19-25mm)3/8 - 1/2 (10-13mm)
1 - 1 1/2 (25-38mm)1/2 (13mm)

Linear Feet Per Gallon

Joint Depth (Inches)Joint Width (Inches)
1/43/81/25/83/47/811 1/223
1/4308205154122------
3/8---82685851---
1/2----514438261912

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