Dowsil 781 Acetoxy Silicone Sealant - 310ml Cartridge

Dowsil 781 Acetoxy Silicone Sealant is a one-part, fast-curing silicone sealant designed for a wide range of applications. Offering good adhesion to various non-porous surfaces, such as glass, aluminium, painted finishes, and composite boards, it is perfect for glazing and weatherproof sealing sheet cladding. This sealant is also ideal for draft-proofing and general interior sealing tasks. It provides strong adhesion and exceptional resistance to ageing, shrinking, cracking, and discolouration, ensuring long-lasting performance in both residential and commercial settings.

• High strength
• Adheres to Aluminum, Glass, Paint and Wood
• Fast cure - tack-free in 30 minutes
• Resist to ozone, ultra-violet radiation and temperature extremes
• Good elasticity
• Conforms to ISO 11600-F&G-20LM

Before applying the sealant, ensure that all surfaces to be sealed are clean, dry, sound, and free from frost, release agents, old sealants, and any other contaminants that could impair adhesion.

• Use a suitable solvent, such as DOWSIL™ R-40 Universal Cleaner, to clean and degrease all surfaces. Wipe down with a clean, oil- and lint-free cloth to ensure a thorough cleaning before sealant application.
• When using any solvent, always ensure that the area is adequately ventilated. Avoid heat, sparks, and open flames during the process. It is also important to wear solvent-resistant gloves for protection and follow all precautions listed on the solvent container label.
• All joint surfaces other than glass and glazed ceramics must be primed before sealant application to ensure optimal adhesion.

The silicone sealant is ready for immediate use. Cut the tip off the cartridge and screw on the nozzle and cut the nozzle to the desired bead size. We recommend using the Geocel Cox Skeleton Gun for application.

• For joints too shallow to accommodate the backer rod, low tack polyethylene tape should be used. This will prevent three-sided adhesion and allow the sealant to perform effectively.
• For optimal performance, the minimum joint width for DOWSIL™ 781 Acetoxy Sealant should be 6 mm.
• For joints that are 6–12 mm wide, the seal depth should be 6 mm to ensure proper adhesion and sealant performance.
• For joints wider than 12 mm, maintain a 2:1 width to depth ratio for the best sealant performance.
• When using the sealant in fillet joints, it is recommended to have a minimum of 6 mm sealant bite to each substrate for an effective seal.
• After applying the sealant, tool the joint within 5 minutes to ensure good contact between the sealant and the substrate. Tooling also provides a smooth and professional finish to the joint for best results we recommend using Bedec Silicone Profilers.
• Any excess sealant on tools and non-porous surfaces can be easily cleaned off while still uncured using DOWSIL™ R-40 Universal Cleaner.

Please Note: If sealant is misapplied to porous surfaces, it should be left until it is just cured. Once cured, it can be removed by peeling, cutting, or using other mechanical methods. Be careful not to damage any plastic or coated surfaces during this process.

By following these application instructions, you will ensure a strong and durable bond with DOWSIL™ 781 Acetoxy Sealant for your sealing needs.

Q. What surfaces can DOWSIL™ 781 Acetoxy Sealant be used on?

A. DOWSIL™ 781 Acetoxy Sealant is suitable for a wide variety of surfaces, including glass, aluminum, ceramic tiles, metal, plastics, and many other non-porous surfaces. It's commonly used for sealing joints in construction, windows, doors, and facades.

Q. Is DOWSIL™ 781 Acetoxy Sealant resistant to temperature fluctuations?

A. Yes, this sealant can withstand temperature changes and is resistant to extreme weather conditions, making it highly effective in both hot and cold environments.

Q. Can DOWSIL™ 781 Acetoxy Sealant be painted over?

A. DOWSIL™ 781 Acetoxy Sealant is not recommended to be painted over after it has cured. It is a non-paintable sealant, so if you require a paintable surface, consider using a different sealant designed for painting.

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.