Dowsil 791 External Weatherproofing Silicone Sealant 600ml - Black

DOWSIL™ 791 Weatherproofing Silicone Sealant is a one-part, low modulus, neutral curing sealant designed for both commercial and domestic applications. It offers exceptional weatherproofing properties and provides excellent adhesion to most porous and non-porous surfaces without the need for a primer. Ideal for general glazing and weather sealing in curtain walls and building facades, this versatile sealant is resistant to ozone, UV radiation, and extreme temperatures, ensuring long-lasting durability and protection.

• Superior Weather Resistance
• Flexible and Durable
• Adheres to a wide range of substrates

Before applying the sealant, ensure that all surfaces to be sealed are clean, dry, sound, and free from grease, dust, or any other contaminants that could affect adhesion.

• For non-porous surfaces (such as glass, aluminum, or PVC), clean them using DOWSIL™ R-40 Universal Cleaner. Apply the cleaner to a clean, lint-free cloth and wipe the surface thoroughly. After cleaning, make sure the surface is completely dry.
• For porous surfaces (such as concrete, brickwork, or mortar), mechanically clean the surface to remove any loose particles or debris. Use tools like a steel brush, sanding disc, or similar methods to ensure a smooth, clean surface.
• After cleaning, check that the surfaces are completely dry and free of any contaminants to ensure proper adhesion of the sealant.

We recommend using the Geocel ecoSEAL Cartridge with the Dowsil 791 External Weatherproofing Silicone Sealant Sausage.

• Begin by installing any necessary backing materials, joint fillers, setting blocks, spacer shims, or tapes to prepare the joint. These materials help ensure proper sealant application and provide back pressure to prevent three-sided adhesion.
• Mask the areas adjacent to the joint to ensure neat, straight sealant lines and to protect surrounding surfaces from excess sealant.
• Primer is generally not required for non-porous surfaces. However, for certain porous surfaces, a primer may be necessary to achieve optimal adhesion. Conduct a test placement on a small area to confirm compatibility.
• Apply DOWSIL™ 791 Silicone Weatherproofing Sealant in a continuous bead using positive pressure. The sealant can be applied with a variety of air-operated guns or bulk dispensing equipment such as the Geocel Cox Skeleton Gun.
• Before a skin forms (typically within 15 minutes), use light pressure to tool the sealant for best results we recommend using Bedec Silicone Profilers. Spread it evenly against the backing material and the joint surfaces to ensure a strong bond.
• As soon as the sealant has been tooled, immediately remove the masking tape for a clean, neat finish.

Always follow manufacturers instructions found on the cartridge.

Q. How does DOWSIL™ 791 cure?

A. The sealant cures by reacting with moisture in the air, transforming into a flexible and durable silicone rubber seal. The curing process occurs at ambient temperatures.

Q. Can DOWSIL™ 791 be used on all types of surfaces?

A. Yes, DOWSIL™ 791 is designed to bond well with a wide range of materials, including glass, metal, ceramics, PVC, and painted surfaces. It is ideal for weatherproofing joints around windows, doors, and other exterior applications.

Delivery - All orders placed on a working day before 3pm will be dispatched on the same day for next working day delivery. Orders placed before 3pm on Friday will be delivered on Monday (excluding bank holidays). Orders placed on weekends and Bank Holidays will be dispatched on the next working day. 

Delivery of Tinted Products - Tinted paints are dispatched in line with our express order process, shown below. However, due to their bespoke nature, please allow up to an additional 5 working days to accommodate any potential courier delays or delivery issues before receiving a refund or replacement.

We strongly suggest customers avoid booking tradespeople until they receive their order. Next Day Paint will not be held liable for any costs incurred due to order processing errors, delivery delays, or other issues that may result in financial loss.

Delivery Options

Express Shipping - £3.99

Order by: 3pm, Monday - Sunday

Expected delivery: Next working day, 8am - 9pm

Orders placed on weekends or bank holidays will be dispatched on the next working day for delivery on the following day

AM Delivery - £12.99

Order by: 2pm, Monday - Sunday

Expected delivery: Next working day by 2pm

Orders placed on weekends or bank holidays will be dispatched on the next working day for delivery on the following AM

Late Cut-Off - £5.99

Order by: 4pm, Monday - Friday 

Expected delivery: Next working day, 8am - 9pm

Orders placed on weekends or bank holidays will be dispatched on the next working day for delivery on the following day

Saturday Delivery - £9.95

Order by: 2pm, Friday 

Expected delivery: Saturday, 8am - 9pm

Standard Delivery (Out of Zone Postcodes Only) - £6.99

Order by: 3pm, Monday - Sunday 

Expected delivery:  3-5  working days, 8am - 9pm

Orders placed on weekends or bank holidays will be dispatched on the next working day for delivery on the following day

We do not deliver to the Channel Islands or the Republic of Ireland

Certain postcodes delivery times and charges may vary please head to the cart to see your available delivery options.

Returns

We offer a 14 day money back guarantee for all goods shipped correctly that are not required. If the item is not required, please send the item back for a full refund in its original condition, unused with its original packaging. Please note return for unwanted item is at your own expense.

Contact us as soon as possible to inform us you will be returning the product either by a contact form or by calling our team on 0161 960 0217.

All tinted paint purchases are final and non-refundable. If you're unsure about your selection, please refer to the product listing or contact us for guidance before ordering. Once mixed, tinted paints cannot be returned or refunded, regardless of delivery delays or changes in circumstances.

While we aim to meet delivery timelines, we are not responsible for delays caused by couriers, weather, or other external factors.

We recommend ordering samples or colour charts before purchasing. While we strive to represent colours accurately, screen settings and surface types can affect appearance. Opened tins cannot be returned due to dissatisfaction with colour.

For non-tinted products, we offer a 14-day money-back guarantee. Items must be returned unused, in original condition and packaging, at your own expense.

Damaged Paint

Please visit our damages page, where we can help resolve the issue for you. 

Incorrect Item

If we have sent you a different item from what you ordered, we will be happy to organise an exchange for the correct goods at no extra charge to yourself, please get in touch to organise this.

Faulty Items

Faulty items can be refunded or exchanged within 30 days. All returns are tested, and if no fault is found, no refund will be issued you'll have the option to have the item returned. For faults discovered after 30 days, please contact the manufacturer for further support.