HB42 Fusion Ultimate Sealant - 290ml

HB42 Fusion Ultimate Sealant is a next-generation hybrid polymer sealant, engineered to fuse the smooth toolability and clean finish of a traditional silicone with the superior strength, flexibility and long-term durability of a modern polymer. The result is a single, versatile sealant that performs where ordinary silicones and acrylics fall short.

Suitable across sanitary, construction, roofing, façade, automotive and marine applications, HB42 Fusion is also safe for use in food preparation areas and on consistently moist surfaces. It's the ideal choice for expansion and construction joints, and for sealing around plastic, timber and metal frames, thanks to excellent anti-mould and UV resistance built to last outdoors and indoors alike.

• Hybrid polymer technology - silicone-like finish, polymer-grade strength
• High movement accommodation - withstands ±20% joint movement without cracking
• Anti-mould & UV resistant - stays cleaner for longer, indoors and outdoors
• Overpaintable - compatible with waterbased paints once cured
• Wide temperature tolerance - service range of -40°C to +100°C
• Multi-surface adhesion - bonds to plastic, timber, metal and more
• Long-lasting - 20+ years life expectancy when applied correctly

• Ensure all surfaces are clean, dry and free from dust, grease, oil or standing water.
• Clean non-porous surfaces (e.g. aluminium) appropriately with a suitable solvent cleaner.
• Prime porous substrates if required - check compatibility on a test area first.
• Check joint dimensions: minimum 6mm x 6mm, maximum 20mm wide x 12mm deep.
• For deeper joints, insert a backer rod before application to control sealant depth and improve movement performance.
• Mask joint edges with tape for a clean, professional finish if desired.

• Cut the cartridge nozzle to the desired bead size and load into a standard cartridge gun.
• Apply the sealant firmly and evenly into the joint, keeping the gun at a consistent angle.
• Tool the sealant within 10 minutes of application for the best finish (a smoothing tool or spatula dipped in soapy water works well).
• Remove masking tape immediately after tooling, before the surface skins over.
• Allow to skin for approximately 15–20 minutes (at 23°C / 50% RH) before disturbing the surface.
• If overpainting, use waterbased paints only, and allow the sealant to fully cure first.

Tip: Work in temperatures between +5°C and +35°C for optimal application and curing performance.

Aftercare & Curing

• Keep the joint free from movement, water contact and dust while curing.
• Cure rate is approximately 3mm per 24 hours - larger beads will take longer to fully cure through.
• Avoid submerging the sealed joint in water; HB42 Fusion is not designed for permanently submerged or aquarium use.
• Once fully cured, the sealant offers excellent long-term resistance to mould growth and UV exposure.

Clean Up

• Wipe away excess uncured sealant immediately with a dry cloth or paper towel.
• Use a suitable solvent (such as isopropyl alcohol) to remove uncured residue from tools and non-porous surfaces.
• Cured sealant can only be removed mechanically (e.g. scraping) - solvents will not dissolve it once fully vulcanised.
• Clean the cartridge nozzle and reseal or replace it for future use to prevent the tube curing in storage.

Storage

Store unopened cartridges in cool, dry conditions between 5°C and 25°C. Under these conditions, shelf life is 12 months. Keep away from direct sunlight and frost during storage and transport (frost resistance during transport is rated to -15°C).

Q. Can HB42 Fusion Ultimate Sealant be used underwater or in aquariums?

A. No. While HB42 Fusion is highly durable and moisture-curing, it is not designed for permanently submerged joints or aquarium use. It performs best in wet or moist environments (like bathrooms) rather than fully submerged applications.

Q. Can I paint over HB42 Fusion once it's applied?

A. Yes, HB42 Fusion is overpaintable, but only with waterbased paints, and only once the sealant has fully cured. Painting over it too early or using solvent-based paints may affect adhesion and finish.

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 after 3pm on Friday, 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

AM Delivery - £12.99

Order by: 4pm, Monday - Sunday

Expected delivery: Next working day by 4pm

Late Cut-Off - £5.99

Order between: 3-4pm, Monday - Friday 

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

Extended Late Cut-Off - £7.99

Order between: 4-5pm, Monday - Thursday

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

Saturday Delivery - £9.95

Order by: 4pm, Friday 

Expected delivery: Saturday, 8am - 9pm

Standard Delivery (Out of Zone Postcodes Only) - £8.99

Order by: 3pm, Monday - Sunday 

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

Note: 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.