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How To Apply MasterSeal® NP 1™ Sealant

MasterSeal®  NP 1 Sealant packaged in 300 ml cartridge, inserted in manual caulk gun
MasterSeal NP 1 Polyurethane Sealant in a 300 ml cartridge package, inserted into a caulking gun

Watch how to apply MasterSeal NP 1, a one-component, high performance, non-priming, gun-grade, elastomeric polyurethane sealant (Video Transcript). Then learn more about the materials, tools and accessories required to do the job safely and efficiently.

MasterSeal NP 1 Sealant Application Video Transcript

  • Ensure substrate is structurally sound, fully cured, dry and clean
  • Use [MasterSeal P 176] primer as necessary
  • If required, install the appropriate size backer rod for the joint
  • When using 300 ml cartridges, cut tip of cartridge for desired width of the sealant bead
  • Puncture foil using a sharp object
  • Insert cartridge into caulking gun
  • When using 20-ounce propaks, insert propak into a bulk caulking gun
  • Open propak with a razor knife, then attach cone to the caulking gun
  • Cut the cone slightly smaller than the width of the joint
  • Fill joint from the deepest point, to the surface
  • Dry tool joints to create a smooth, concave shape
  • Refer to the MasterSeal NP 1 technical data guide for more information.

Sealant Application Materials, Tools and Accessories

Materials, Tools and Accessories – Shown

  • Protective Gloves – 4-mil nitrile, disposable glove
  • Protective Clothing – Long-sleeve sweatshirt
  • MasterSeal P 176 Primer – High-solids, low-VOC, solvent-based primer for priming joints and substrates
  • Brush
  • Backer Rod – Closed-cell, polyethylene foam, joint filler
  • Wooden Rod, Tapered – Used to press the backer rod completely into the joint
  • MasterSeal NP 1 Sealant, 300 ml Cartridge Package – Preferred for smaller sealant applications
  • Razor Knife
  • Caulking Gun – Manual Cartridge Gun
  • MasterSeal NP 1 Sealant, 20-Ounce ProPak Package – Economical and efficient for larger sealant applications
  • Bulk Caulking Gun – Manual Bulk Gun
  • Bulk Caulking Gun Cone
  • Caulk Spatula – Give a smooth, concave shape to the sealed joint.

Precautionary Accessories – Not Shown

Refer to the MasterSeal NP 1 Safety Data Sheet (SDS) for more information.

  • Eye Protection
  • Face Protection
  • Respiratory Protection – In case of inadequate ventilation
  • Tool Belt.