BOSS - 03422BK10 - 139 Hi-Temp Mortar, Black

Item: BOSS13910
MFG: 03422BK10
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Boss® 139 Hi-Temp Mortar Is A Non Combustible Silicate Cement That Can with Stand Extremely High Temperatures. Formulated For Repairing Chimneys, Fireplaces and Sealing Wood-Burning Stoves and Appliances, This Product Has Strong Adhesion and Sets To Become Rock Hard When Fired.

Boss® 139 Hi-Temp Mortar Cannot Be Used In Areas Where There Is Constant Movement, or Where Wet Conditions Exist or May Occur.

Boss® 139 Hi-Temp Mortar Has Been Tested and Exceeds Astm E-136. Can Be Used In Wood Frame Construction Where An Astm E-136 Non Combustible Sealant Is Specified and Where Allowed By The Building Code. This Includes Sealing Around Pipes, Ducts, Vents and Chimneys At Ceiling and Floor Level Before Drywall Is Applied.


  • Can with Stand Extremely High Heat
  • Apply Using A Standard Caulking Gun
  • Dries Rock Hard When Cured and Fired
  • Safe To Use and Handle
  • No Harmful Odors
  • Water Clean-Up (Prior To Curing)
  • Voc Compliant
  • Contains No Asbestos Fillers Of Any Kind
  • Meets Residential Construction Code Approvals Including I.R.C.

California residents: see Proposition 65 Warning

Features and Specification

Weight 1.500000
Package Weight 18.000000
Length 2.000000
Standards ASTM E-136, IBC/IRC, BOCA National building Code, CABO one and two family dwelling code, UBC Section 796, BOCA-SBCCI-ICBO-NFPA Building Codes
Size 10.1 Ounces
Package Width 7.875000
Package Height 9.312500
Package Length 5.875000
Temperature Range 0°F to 800°F (-17.7°C to 426.6°C)
Width 2.000000
UV Resistant No
UPC 787930139108
UL Recognized No
UL Listed No
Type Fire Block
Application Hi-Temp Non-Combustible Mortar For Repairing Chimneys, Fireplaces, And Sealing Wood Burning Stoves And Appliances.
Brand BOSS®
Color Black
Comments/Notes Can Contribute Credits
Composition Silicate Cement
Cubic Measurement 0.019100
EAN 0787930139108
Dimensional Weight 3.000000
Includes 4 Inch Nozzle
Height 8.250000
Functions Fire Block, Draft Stop, Sealing


picture_as_pdf safety data sheet

picture_as_pdf specification sheet