NBS Source


Suitable for:

  • High strength applications.
  • Secondary sealant for gas filled triple and double glazed units.
  • Insulating glass applications for structurally glazed facades.


Dowsil 3363 Insulating Glass Sealant is a two-part, neutral curing silicone formulation for insulating glass applications.

Features and benefits:

  • Economical joint sizes in high strength IG applications.
  • High design strength (0.21 MPa) allowing joint size reduction up to 30%.
  • Enhanced productivity with reduced joint dimensions.
  • European Technical Approval ETA 13/0359.
  • Structural capability as secondary sealant for insulating glass in structural glazing applications.
  • Outstanding adhesion to a wide range of substrates including coated and reflective glasses, aluminium and steel spacers, and a variety of plastics.
  • Meets EN 1279 part 4 and 6 and EN 13022.
  • Tested according to EN 15434.
  • Meets the requirements of CEKAL.
  • Low water absorption.
  • Excellent temperature stability: -50°C to 150°C.
  • Non-corrosive cure.
  • Fast curing time.
  • Outstanding resistance to ozone and ultraviolet (UV) radiation.
  • High modulus which limits the stress on the primary sealant and makes it particularly suited for gas-filled insulating glass units.


  • DOWSIL™ 3363 Insulating Glass Sealant should be mixed in a ratio of 10:1 base to curing agent by weight.
  • At this mix ratio, the sealant typically exhibits a working time of 5–10 minutes and allows units to be handled within two hours.
  • Slight variations in mixing ratio can be tolerated, but these should not exceed 11:1 to 9:1 by weight to ensure minimum properties are obtained.
  • It is recommended that the base and curing agent are thoroughly mixed using an airless mixing system

General information



Curing agent.








Pr_30_31_76_78 Silicone glazing compounds and sealantsPrimary


B12/370 Insulating glass units

B12/35 Insulating glass units

L40/655 Insulated glass units (IGUs)

L40/60 Insulated glass units

Specification data - Silicone glazing compounds and sealants Enhanced data


To EN 1279 part 4 and 6, EN 13022, EN 15434 and ISO 8339.

Third party certification



White and black.

Tensile strength (MPa)

As mixed.

1.5 MPa.

  • Design stress in tension: 0.21 MPa.
  • Design stress in static shear: 0.011 MPa.

Specific gravity

Base: 1.38, Curing agent: 1.05, Mixed: 1.33.


7.5 Pa.s.

Curing agent as supplied.

Hardness (shore A)

As mixed.


Elastic modulus

4.8 MPa.

In tension or compression.

Water vapour permeability

18 g/m2/ 24h.


Gas permeability: 0.46 g/ (m2/h).

Service temperature range

-50 to +150°C.

Shelf life

14 months.

  • When stored at or below 30°C, DOWSIL™ 3363 Insulating Glass Sealant Curing Agent has a usable life of 14 months from the date of production.
  • When stored at or below 30°C, DOWSIL™ 3363 Insulating Glass Sealant Base has a usable life of 14 months from the date of production.



DOWSIL™ 3363 Insulating Glass Sealant Base.


DOWSIL™ 3363 Insulating Glass Sealant Catalyst.


Not required.

DOWSIL™ 3522 Cleaning Solvent Concentrated.

This solvent dissolves cured silicone sealant and provides optimum cleaning performance.

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