Dowsil 121 Structural Glazing Sealant is a neutral-cure, RTV silicone sealant ideal for repair or replacement of structurally glazed glass and other substrates. It is equally suitable for on-site structural glazing including storefront systems or attachment of panel stiffeners as it is for in-shop structural glazing. Facade contractors and manufacturers now have a high-performance solution to the challenges posed by slow-curing one-part sealants, mixing challenges of multipart sealants and limited movement capability of tapes. Dowsil 121 Structural Glazing Sealant answers those challenges with a fast-cure, easy-to-install formulation.


  • Meets Industry Standards
  • ASTM C719 Class 25 (G, A, O)
  • ASTM C1184 Structural Sealant Specification
  • Easy-to-use, 1:1 mix ratio for simplified dispensing
  • Fast, 24/48 -hour cure
  • Joint movement capability of (+/-25%)
  • Available in black 400 ml (2 x 200 ml) cartridges
  • Adheres to Dowsil brand structural sealants for reglazing applications
  • Achieves adhesion and structural strength in 24 to 48 hours
  • Structural Adhesion Limited Warranty available on request. Please contact Glasscorp before project starts.
  • Easy-to-use, user-friendly dispensing
  • Compared with one-part sealants, Dowsil 121 Structural Glazing Sealant offers increased efficiency and productivity
  • Repairs can be completed in just one day (24 hours) compared with 14-21 days
  • Requires use of Glasscorp pneumatic 121 dispensing gun


  • Structural and non-structural glazing and weather sealing
  • Structural attachment of many panel systems
  • Panel stiffener applications


  • Requires use of Glasscorp pneumatic 121 dispensing gun
  • Some applications may require the use of a specific Dowsil primer
  • For more information on compatibility with other products and specialist advice, please contact Glasscorp directly
  • Customers should independently determine the suitability of this product for their specific purpose prior to use


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