Foster® Flextra® Sealant 95-50

1 of 92 products in this brand
Foster® Flextra® Sealant 95-50 is a single-component sealant primarily composed of butyl rubber. It serves as a vapor barrier sealant, typically applied in the joints of various insulation materials, including cellular glass, polyisocyanurate (PIR), urethane, and phenolic foam board stock insulations. This sealant maintains its soft and flexible properties, safeguarding insulation from damage caused by thermal cycling across a wide temperature range.

Product Type: 1K (1 component) Sealant

Compatible Substrates & Surfaces: Glass, Phenolics, Polyisocyanurate

Application Method: Trowel

Features: Flexible, Vapor Barrier

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Identification & Functionality

Features & Benefits

Ready-to-Use Product Features
Product Highlights
  • Flextra® Sealant is primarily used with low temperature insulation to prevent the migration of water and water vapor into the insulation system via butt joints.
  • Flextra® Sealant is also recommended as a bedding compound for the installation of cellular glass insulation. In this application, it protects both the insulation from abrasion and metal surfaces from corrosion.
  • Flextra® Sealant is supplied in a special “buttery” consistency, which facilitates application to insulation surfaces without stringing or excessive drag.
  • It may be applied at temperatures as low as 50°F (10°C) without difficulty.
  • Flextra® Sealant meets requirements for LEED IEQ 4.1 Low-Emitting Materials, Adhesives and Sealants.
  • VOC: <420 g/l, less water and exempt solvents.
  • Flextra® Sealant contains no asbestos, lead, mercury, or mercury compounds.

Applications & Uses

Application Method
Compatible Substrates & Surfaces
Limitations
  • Always test solvent plastic materials for compatibility when using a solvent base product.
  • Not suggested for use under solvent base mastics and coatings, if minor surface discoloration and/or dirt pick-up would be objectionable.
  • Discoloration can be minimized by allowing 24 to 48 hours cure time before top coating.
  • Do not use this product where surface temperature will exceed 200°F (93°C).
  • Not suggested for use as a flashing compound.
Preparation and Application Information

Material Preparation

  • Do Not Thin. 
  • Apply only to clean, dry, oil-free surfaces.
  • Keep container closed when not in use.

Application 

  • Apply by trowel, putty knife or power extrusion.
  • When sealing insulation joints, apply FLEXTRA® to the edges of abutting sections at 1/16 in. to 1/8 in. (1.6 to 3.2 mm) wet film thickness and press mating surfaces together firmly to squeeze out air bubbles and to obtain complete contact.
  • Strike off excess sealant on surface with trowel.

Power Extrusion

  • Flextra® Sealant may be applied using a wide variety of power (pressure) extrusion equipment suitable for use with solvent base sealants.
  • It has a soft and buttery consistency with a typical viscosity range of 225,000-325,000 cps (HBT, 5 rpm).
  • Note: Pressurized piping made from copper and aluminum alloys may be susceptible to under insulation corrosion when in direct contact with many materials. When used as a joint sealant direct contact between pressurized pipes made from these metals and the sealant should be prevented.

Clean Up

  • Use solvent such as chlorinated solvent (non-flammable) or mineral spirits (flammable) for cleaning tools and equipment.

Properties

Physical Form
Typical Properties
ValueUnitsTest Method / Conditions
Average Weight / U.S. Gallon11.6lbs.ASTM D1475
Average Non-Volatile (by Volume)82.0% -
Average Non-Volatile (by Weight)73.0% ASTM D2369
Average Non-Volatile (by Weight)89.0% -
Flash Point145°F
Coverage Range (Trowel)12 - 25sq. ft./gal.FSTM 71
Drying Time (Skins Over)2 - 3Hours-
Application Properties
ValueUnitsTest Method / Conditions
Service Temperature Range (Cellular Glass, at coated surface)-150 to 200°F
Service Temperature Range (Pir / Urethane Foam, at coated surface)-261 to 200°F
Water Vapor Transmission Rate

The water vapor transmission through 1 in. of impermeable insulation in 12 x 18 in. blocks with 1/8 in. joints of 95-50 is too small to measure. Test method : ASTM E 96

Combustibility

Combustible. Flame spread and fuel contribution negligible when used as sealant in 1/8 in. wide joints of incombustible insulation.

Regulatory & Compliance

Storage & Handling

Shelf Life
6 months
Storage Condition

Store and apply between 40°F and 100°F