Foster® Cryolar™ 1K Vapor Stop Sealant 90-61

1 of 184 products in this brand
Foster® Cryolar™ 1K Vapor Stop Sealant 90-61 is a ready-to-use, one-component vapor stop sealant specifically designed for use in cryogenic applications. It is formulated with select synthetic rubbers to create an elastomeric vapor barrier film capable of spanning the temperature ranges encountered in cryogenic processes, including LNG, ethylene, and ammonia production. This sealant is suitable for application to various insulation materials like PUR and PIR foam, cellular glass, and other rigid insulations. It can be used in conjunction with aluminum, steel, and masonry construction materials.

Product Type: 1K (1 component) Sealant, Sealant

Application Area: Cryogenic Applications

Compatible Substrates & Surfaces: Aluminum, Masonry, Metal, Polyurethane (PU) Foam, Stainless Steel

Application Method: Brush, Trowel

Features: Moisture Resistant

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Identification & Functionality

Features & Benefits

Ready-to-Use Product Features

Applications & Uses

Application Area
Application Method
Coverage Range
  • Subject to type of surface being coated.
  • 3.5 to 4.0 gal./100 sq. ft. (1.43 to 1.63 l/m2) on a smooth non-porous surface.
  • Porous or rough surfaces will require higher gallonage to attain required dry thickness
  • Dry Thickness: 0.025 to 0.028 in. (0.64 mm to 0.71 mm)
  • Equivalent Wet Coverage: 0.056 in. to 0.064 in. (1.42 mm to 1.63 mm)
Recommended Applications

Cryolar™ 1K Vapor Stop is designed for vapor stop applications on insulated cryogenic pipelines and equipment. It can also be used on very low temperature applications to seal seams where a water vapor tight insulation system is required.

  • Store and apply between 40°F and 100°F.
  • Always test plastic materials for compatibility when using a solvent-based product. Do not use on polystyrene insulation.
  • Always allow the sealant to dry completely before covering with impermeable materials.
  • Not suggested as an exposed sealant for extended periods of time.
  • Use caution when installing peel and stick membranes directly over 90-61. Removing or repositioning will damage the vapor stop surface.
Preparation and Application Information

Material Preparation

  • Stir well. Do not thin. Apply only to clean, dry surfaces. Keep container closed when not in use to prevent solvent evaporation.


  • Apply a tack coat at 2 gal./100 sq. ft. (0.8 l/m2), 31 mils (0.8 mm) wet film. Embed Foster Mast-a-Fab® reinforcing mesh, being sure to smooth all wrinkles and allow to set. Follow with a finish coat of 90-61 sealant at a rate of 2 gal./100 sq. ft. (0.8 l/m2), 31 mils (0.8 mm) wet film. Reinforcing mesh must be used for cryogenic applications. Finished dry film shall be 23 mils (0.9 mm) dry film thickness minimum.
  • When applying over rough or porous surfaces increase the coating volume to fully seal the surface leaving a minimum 31 - 35 mils (0.8 - 0.9 mm) dry film thickness on the surface. Inspect for pinholes and over coat as necessary to complete a pinhole free finish.
  • This may take 50% more material to achieve a full coating film with mesh embedded. Note: The pattern of the mesh may still be visible, but it must be completely covered.
  • When selecting mesh reinforcement Foster Mast-A-Fab is strongly recommended based on its mesh size, membrane thickness and flexibility. In all cases the mesh must be an open weave mesh allowing it to be embedded into the wet 90-61 sealant and be sufficiently thin such that the dried 90-61 film covers the entire mesh. Too thick a mesh may prevent formation of a full film with the mesh embedded completely.
  • Always allow the 90-61 to fully dry before covering with abutting insulation or jacketing.

Clean Up

  • Use solvents such as chlorinated solvents (non-flammable) or MEK (flammable) for cleaning tools and equipment. Completely clean all equipment before sealant sets up.


Physical Form
Typical Properties
ValueUnitsTest Method / Conditions
Average Weight / U.S. Gallon9.3lbs./gal.ASTM D1475
Average Non-Volatile (by Volume)45.0% ASTM D2369
Average Non-Volatile (by Weight)57.5% ASTM D2369
Water Vapor Permeance (at 100°F, 90% RH, 0.020 – 0.025 in. dry film thickness)max. 0.01permsASTM F1249
Flash Point115°F
Drying Time (at 73°F, 50% RH, to touch)2 - 3hours
Drying Time (at 73°F, 50% RH, through)24hours
Application Properties
ValueUnitsTest Method / Conditions
Service Temperature Limits (at coated surface)-320 to 250°F

Regulatory & Compliance