Insulating Glass Sealant. 

  • Insulated glazing for residential and commercial glazing.
  • Insulated glazing incorporating speciality glass (pyrolithic of soft coated, laminated, tinted, enamelled) types, stepped glass or with free edges.
  • Insulated glazing for applications under extreme conditions of humidity and temperatures, high or low.
  • Insulated glazing used in greenhouses and skylights under high sun exposure.
  • Adhering and jointing of glass elements.
  • Excellent adhesion to coated or reflective glass, aluminium or galvanized steel spacers.
  • Fast cure one-component technology, ideal for use at low temperature and/or low humidity in workshops.
  • Minimum waste and downtime by eliminating base purging and static mixer maintenance.
  • Packaged for both manual and robot applications.
  • Outstanding aging properties.
  • Silicone technology providing outstanding UV resistance.
  • Service temperature range -40°C (-40°F) to up to 100°C (212°F).
  • Non-slumping, permitting ease both of manual and automated glazing.
  • Non-corrosive cure.
  • Solvent-free.
  • Low water absorption.
  • High level of mechanical properties.
  • Does not contain organic plasticizer that can cause fogging in the IG air space.
  • Resistance to ozone.
Typical Properties

Specification writers: These values are not intended for
use in preparing specifications. Please contact your local DOWSIL® sales representative prior to writing specifications on this product.

Test method* Property Unit Value

CTM 0364

As supplied Colour   Black,
Consistency   Non-slumping, viscous paste
Specific gravity kg/litre 1.33
Extrusion rate (nozzle 6mm at 6.2 bar) g/minute 140
Application temperature °C
5 to 40
41 to 104
 After application
CTM 0364 Slump mm 1.0
Working time 23°C (73°F) at 50% R.H. minutes 5-10
Skin-over time 23°C (73°F) at 50% R.H. minutes 10-15
TFT tack-free time minutes 25
Curing time 23°C (73°F) at 50% R.H. mm 3.8mm/24hours
Curing time 23°C (73°F) at 50% R.H. mm 8.0mm/72hours

See Figure 1 and 2 for different conditions

Performance Testing

Insulating glass unit sealed with DOWSIL® 3540 Silicone Sealant has been successfully evaluated by CEBTP following the French norm NFP 85-516 for 2000 hours UV resistance.
Insulating glass unit sealed with DOWSIL® 3540 Silicone Sealant are also tested regularly by CEKAL (France).

DOWSIL® 3540 Silicone Sealant has been tested by INV as per prEn 1279-4 with the reference HW/GL/MAS/97/BE.95C.

The performance of the unit sealed with DOW CORNING® 3540 Silicone Sealant greatly exceeds the specifications laid down in British Standard BS 5713 and the German Standard DIN 1286 I for dual sealed units.

Cure Properties

The figures 1 and 2 correlate the DOWSIL® 3540 Silicone Sealant cure in depth, expressed in mm of thickness of the joint calculated from the spacer lower part to the glass edge, with the room conditions of temperature and humidity after 12 hours (Figure 1) and 24 hours (Figure 2).


After 24 hours at 23°C (73°F) and 50% R.H. the cure in depth is 3.6mm.

Surface Preparation

Ensure that surfaces to be sealed are clean, dry and free from frost. Clean all surfaces of release agents, water, repellents, laitance, dust, dirt, old sealants and other contaminants that could impair adhesion. Non-porous surfaces should be cleaned and degreased by wiping with a suitable DOWSIL® R40 Universal Cleaner on an oil and lint-free cloth before application of sealant.

NOTE: When using any solvent, always provide adequate ventilation. Avoid heat, sparks and open flames. Use solvent resistant gloves. Observe and follow all precautions listed on solvent container label.


If direct adhesion of DOWSIL® 3540 Silicone Sealant is needed, official approval of the glass manufacturer is required with regard to the long-term adhesion of the coating to the glass. If there is any doubt concerning adhesion of the coating to the glass, the coating shall be removed from the area where the sealant will come in contact with the glass. Experience shows that good adhesion is usually obtained on clear and tinted float glass and on hard pyrolithic coatings. However, adhesion should be checked on soft magnetron coatings, silkscreen enamelled coatings and on non-float coloured glass (for instance stained-glass) or on glass where the composition is different from the usual borosilicate glass manufactured with a float process.

Handling Precautions

Product safety information required for safe use is not included. Before handling, read product and safety data sheets and container labels for safe use, physical and health hazard information.

The material safety data sheet is available o the DOWSIL® website at You can also obtain a copy from your local DOWSIL® sales representative or Distributor or by calling your local DOWSIL® Global Connection.

Usable Life & Storage

When stored in cool, dry conditions below 25°C (77°F) in the original unopened containers, DOWSIL® 3540 Silicone Sealant has a usable life of 9 months from the date of production.


DOWSIL® 781 Silicone Sealant is supplied in 600ml sausages packed in box of 20, in 20 litre pails and 250kg drums.

DOWSIL® references are:

3283917: DOWSIL® 781 Silicone Sealant sausages 600ml (Colour black)
3283488: DOWSIL® 781 Silicone Sealant pails 20 litre (Colour black)
3283241: DOWSIL® 781 Silicone Sealant drums 225kg (Colour light-grey)
4030263: DOWSIL® 781 Silicone Sealant drums 250kg (Colour black)


DOW CORNING® 781 Silicone Sealant should not be applied:

  • As a primary or single seal of an insulating glass unit
  • As a structural glazing sealant or as a secondary barrier seal of an insulating glass unit.

The following products are available for these applications:

Ask for DOW CORNING® specific products:

DOW CORNING® 3793 and DOW CORNING® 3362 for insulating glass
DOW CORNING® 895 and DOW CORNING® 993 for structural bonding (ask for advice about this application)

  • To areas where food contact is likely
  • In totally confined spaces, as the sealant requires atmospheric moisture to cure and in addition, releases by-products during the curing process
  • For continuous use in submerged joints or in joints where physical abuse or abrasion are likely to occur
  • In contact with bituminous substrates, substrates based on natural rubber, chloroprene or EPDM, or on building materials which might bleed oils, plasticizers or solvents, on green or partially vulcanized rubber gaskets and tapes.

This product is neither tested nor represented as suitable for medical or pharmaceutical uses.

Health & Environmental Information

To support customers in their product safety needs, DOWSIL® has an extensive Product Stewardship organisation and a team of Product Safety and Regulatory Compliance (PS&RC) specialist available in each area.

For further information please see our website, or consult your local DOWSIL® representative.

Limited Warranty Information – Please read carefully

The information contained herein is offered in good faith and is believed to be accurate. However because conditions and methods of use of our products are beyond our control, this information should not be used in substitution for customers’ tests to ensure that DOWSIL®s products are safe, effective and fully satisfactory for the intended end use. Suggestions of use shall not be taken as inducements to infringe any patent.

DOWSIL®’s sole warranty is that the product will meet the DOWSIL® sales specifications in effect at the time of shipment. Your exclusive remedy for breach of such warranty is limited to refund of purchase price or replacement of any product shown to be other than as warranted.


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