X-traseal - Spectrem 2 - Sealant

Spectrem® 2 is a medium-modulus, single-component, high-performance, neutral-cure silicone sealant ideal for a variety of perimeter caulking and glazing applications.

Basic Uses
  • Two-sided structural glazing
  • Perimeter and weather seals
  • Cap, heel and toe beads
  • Curtain wall or window joints

Spectrem 2 may be used on substrates such as aluminium, glass, steel, painted metal, plastic, stone, concrete and brick. Spectrem 2 exhibits primerless adhesion to many common building materials.

Spectrem 2 meets or exceeds the requirements of the following specifications:

  • ASTM C920 Type S, Grade NS, Class 50, Use NT, M, G, A and O
  • ASTM C1248
  • U.S. Federal Specification TT-S-001543A (COM-NBS) Class A
  • U.S. Federal Specification TT-S-00230C (COM-NBS) Class A, Type II
  • CAN/CGSB 19.13-M87
  • Black meets all of AAMA 802.3-92 (Type I and II), 805.2-94 (Group C), and 808.3-92
Joint Design

May be used in any joint designed in accordance with accepted architectural / engineering practices. Joint width should be 4 times anticipated movement, but not less than 1/4” (6 mm) wide.

Joint Dimensions

For joints 1/4” to 1/2” wide (6 mm to 13 mm), the width-to-depth ratio should be equal. Joints 1/2” wide (13 mm) or greater should have a depth of 1/2” (13 mm). Minimum joint size is 1/4” x 1/4” (6 mm x 6 mm).

Surface Preparation

Surfaces must be sound, clean, and dry. Contact surfaces should be free of loose dirt, dust, oils, and any other contaminants.

Tooling & Cleaning

Tooling is recommended immediately after application to ensure firm, intimate contact with the joint interface. Dry tooling is preferred. Cleaning can be accomplished with solvents such as Xylene, Toluene or MEK while sealant is in an uncured state.

Joint Backing - Bond Breaking Tape

Closed cell polyethylene backer rods are preferred as joint backing to control depth of sealant bead. Where depth of joint will prevent use of joint backing, an adhesive-backed polyethylene tape should be installed to prevent three-sided adhesion. Joint backing must be dry at time of sealant application.


Spectrem 2 is easy to apply with conventional caulking equipment. Fill joint completely and tool. At 75 ̊F (23.9 ̊C), 50% R.H. a durable skin will form typically within less than 10 min. Please visit www.tremcosealants.com for complete application instructions.


Damaged sealant can be repaired.

  • Do not apply to damp or contaminated surfaces.
  • Use with adequate ventilation.
  • Clear silicones are not recommended for structural glazing applications.
  • Not intended for continuous water immersion.

    Technical Data Sheets