NBS Source

Application

Suitable for structural bonding of glass, metal and other building components.


Method:

  • DOWSIL 993 Structural Glazing Sealant should be mixed in a ratio of 10:1 base to curing agent by weight, or equivalent 7.8:1 by volume for optimal properties.
  • At this mix ratio, the sealant typically exhibits a working time of 10 to 30 minutes and allows units to be handled within two hours.
  • Small variations in mixing ratio can be tolerated, but these should not exceed 11:1 to 9:1 by weight or 8.9:1 to 7.3:1 by volume to ensure minimum properties are obtained.
  • DOWSIL 993 Structural Glazing Sealant Curing Agent will react with atmospheric moisture and therefore should not be exposed to air for prolonged periods of time.


Description

Dowsil 993 Structural Glazing Sealant is a two-component, neutral curing silicone formulation. Neutral alkoxy; cures at room temperature giving off a small amount of alcohol.


Features and benefits:

  • Meets European standard for structural glazing as developed by EOTA working groups.
  • Excellent adhesion to a wide range of substrates including coated, enamelled and reflective glasses, anodised and polyester paint coated aluminium and stainless steel.
  • High level of mechanical properties.
  • Odourless and non-corrosive cure.
  • Excellent stability through wide temperature range: -50°C to 150°C.
  • Resistant to ozone.
  • Stable viscosity for A & B components, no heating required.
  • Suitable for use in impact-resistant window systems in new construction and retrofit in existing buildings.
  • Structural capability.
  • The cured product exhibits excellent weathering characteristics, and a high resistance to ultra-violet radiation, heat and humidity.
  • Lot matching of base and curing agent not necessary.
  • Different grey shades available (please refer to our colour card).


Preparation:

  • Clean all joints and glazing pockets, removing all foreign matter and contaminants such as grease, oil, dust, water, frost, surface dirt, old sealants or glazing compounds and protective coatings.
  • Metal, glass and plastic surfaces should be cleaned by mechanical or solvent procedures.
  • Test adhesion prior to use.
  • Before use it is recommended that the curing agent be stirred to ensure homogeneity of all components.

General information

Color

Black

Catalyst.

Grey

Catalyst.

White

Base.

Material

Silicone

Shape

Formless

Uniclass

Pr_30_31_76_78 Silicone glazing compounds and sealantsPrimary

CAWS

H13/115 Structural glass assembly

Specification data - Silicone glazing compounds and sealants Enhanced data

Standard

To ISO 11431, ISO 9227, ISO 3231, ISO 8339.

Third party certification

CE Marked.

Material

Neutral cure.

Colour

White and black.

White and grey.

Tensile strength (MPa)

As cured after seven days at 25°C and 50% RH.

0.95 MPa.

Specific gravity

Before mixing:

  • Base (white): 1.32.
  • Catalyst (black): 1.05.
  • HV/ GER (black): 1.06.
  • Catalyst (clear and grey): 1.01.

As mixed: 1.30.

Viscosity

Before mixing:

  • Base 100s (white): 150 000 mPa.s.
  • Catalyst 20s (black): 25 000 mPa.s.
  • HV/ GER 20s (black): 100 000 mPa.s.
  • Catalyst 20s (clear and grey): 25 000 mPa.s.


As mixed: 40 000 mPa.s.

Flash point

+28°C.

Closed cup.

Tear strength

As cured after seven days at 25°C and 50% RH.

6.0 kN/m.

Elongation at break

As cured after seven days at 25°C and 50% RH.

130%.

Hardness (shore A)

As cured after seven days at 25°C and 50% RH.

40.

Dynamic loading

As cured after seven days at 25°C and 50% RH.

140 000 Pa.

Static load resistance

As cured after seven days at 25°C and 50% RH.

11 000 Pa.

Service temperature range

As cured after seven days at 25°C and 50% RH.

-50 to +150°C.

Shelf life

14 months.

  • When stored at or below +30°C, DOWSIL 993 Structural Glazing Sealant Curing Agent has a usable life of 14 months from the date of production.
  • When stored at or below +30°C, DOWSIL 993 Structural Glazing Sealant Base has a usable life of 14 months from the date of production.

Components

DOWSIL 993 Structural Glazing Catalyst.

A medium viscosity paste, fast cure, which is suitable for meter mix equipment using a pressure pot or follower plate system for the catalyst.

DOWSIL™ 993 HV/GER Structural Glazing Catalyst.

A viscous paste, fast cure, which is suitable for meter mix equipment that uses a follower plate system for the catalyst.

Accessories

Not required.

DOWSIL™ 3522 Concentrated Cleaning Solvent.

  • If cured sealant has built up inside the equipment, flush the equipment for the appropriate time with DOWSIL 3522 Concentrated Cleaning Solvent, using a solvent recirculation system.
  • This solvent dissolves cured silicone sealant and provides optimum cleaning performance.

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