Top brands
We only distribute the best
Free next day delivery
on selected in-stock items
Bulk order discounts
Call 01708 855698
Dowsil 781 Medium HM Sealant
Standard Delivery 3-5 Days
If all of your items are available for click & collect, you'll be able to select a location for pickup at checkout.
Stock availability for Dowsil 781 Medium HM Sealant
Leeds
Unit 14 Gelderd Trading Estate, West Vale, Leeds, , LS12 6BD, .
Glasgow
Unit 30 Deerdykes View, Westfield, Cumbernauld, Glasgow, G68 9HN, .
Essex
The Garage Unit. The Forge, Ockendon Road, North Ockendon, , RM14 3PS, .
Caldicot
Unit 16A Norman Way, Severn Bridge Industrial Estate, Caldicot, Monmouthshire, NP26 5PT, .
Orders placed before 2pm Monday – Friday (excluding Bank Holidays) will be dispatched the same day if ‘Next Day Delivery’ is displayed on the product listing. Orders placed after this time will be dispatched the following working day.
Orders for non-stock items will be dispatched within 3-5 working days unless contacted by Customer Services.
Saturday and timed deliveries are available on request. Please contact [email protected] or call 01708 855 698 for more information.
Please note postcodes in some areas of the Scottish Highlands and offshore addresses require a delivery surcharge and in some cases can take longer to be delivered. Please contact [email protected] or call 01708 855 698 for a delivery quote.
AB36-38, AB55-56, FK17-21, G83, GY9, HS1-9, IM (ALL), IV (ALL), JE (ALL), KA27, KA28, KW0-14, KW15-17, PA20-78, PH15-18, PH19-29, PH32-33, PH45-48, PH30-31, PH34-44, PH49-99, PO38, ZE (ALL)
It is the customers responsibility to provide an accurate delivery address. If the courier is unable to deliver your order due to issues with access to the delivery address, your goods will be returned to the local delivery depot for delivery on the next working day. Please note a redelivery charge of up to £89 plus VAT per pallet may be applied. If your order is undelivered and returned to us a restocking fee may also be applied.
Please inform us of any delivery restrictions (eg weight restrictions, narrow roads). Failure to do so may incur a redelivery charge if the courier cannot access the delivery address due to undeclared or incorrect delivery restrictions. A redelivery charge of up to £89 plus VAT per pallet may be applied.
If your order is over 150kg it may be delivered on a pallet. The courier will notify you of a two hour delivery window. In the event that no one is available at the address to receive the delivery a charge of up to £89 plus VAT per pallet may be applied for redelivery.
You may also like
Sikasil 825 Low Modulus Silicone Sealant 380ml
Dowsil 781 Medium HM Sealant FAQs
What is Dowsil 781 Acetoxy Sealant used for?
Dowsil 781 is a one-part, medium/high modulus acetoxy silicone sealant designed for sealing non-porous surfaces such as glass, aluminium, painted surfaces, and composite boards. It offers excellent adhesion, durability, and resistance to ozone, UV radiation, and temperature extremes. It is commonly used in glazing and general sealing applications.
What are the key features and performance properties of DOWSIL 781
-
High strength and elasticity
-
Conforms to ISO 11600-F&G-20LM performance standard
-
Resistant to weathering, UV, and temperature extremes
-
Skin-over time: ~14 minutes at 23°C and 50% RH
-
Tensile strength: 1.8 MPa
-
Elongation at break: 520%
-
Hardness: Shore A 22
-
Joint movement capability: ±20%
How should surfaces be prepared before applying Dowsil 781
All surfaces must be clean, dry, and free from dust, oils, and old sealants. Dow recommends wiping surfaces with Dowsil R-40 Universal Cleaner using a lint-free cloth. Masking adjacent areas is advised for neat application, and priming is recommended on substrates other than glass or glazed ceramics.
Are there any materials or conditions where Dowsil 781 should not be used?
Yes. Dowsil 781 is not suitable for:
- Porous substrates (e.g., concrete, stone, marble, granite)
- Bituminous materials or those containing natural rubber, EPDM, or chloroprene
- Submerged joints, or where abrasion or physical abuse is expected
- Structural or insulated glazing applications
- Food contact or aquarium use
It should not be used in confined spaces, as it requires atmospheric moisture to cure.
What are the storage and packaging details for Dowsil 781?
- Packaging: 310 ml cartridges, supplied in boxes of 12
- Storage conditions: Store in a cool, dry place below 30°C (86°F)
- Shelf life: 27 months from the date of manufacture when unopened and properly stored