AI Summary

Product: Selleys 630 Low Modulus Multipurpose Elastic Joint Sealant Brand: Selleys (a division of DuluxGroup Australia Pty Ltd) Category: Elastomeric sealant / flexible joint sealant Primary Use: Sealing and bonding movement joints across a wide range of building substrates in residential and light commercial applications.

Quick Facts

Best For: Expansion joints, perimeter sealing around windows and doors, construction joints in cladding and façade systems, and general gap-filling where joint movement is expected
Key Benefit: Low modulus formulation accommodates significant joint movement — expansion, contraction, vibration, and settlement — without cracking or pulling away from the substrate
Form Factor: Paste in 300mL cartridge; available in grey, white, and black
Application Method: Dispensed via standard caulking gun; tool immediately with wet finger or spatula before skin formation begins

Common Questions This Guide Answers

How does Selleys 630 cure? → Through exposure to ambient humidity (water vapour in the air); no mixing, heat, or UV required; cures from the outside inward
What is the approximate coverage per cartridge? → Approximately 42 linear metres per 300mL cartridge at a 6mm wide × 6mm deep bead; wider or deeper joints reduce coverage proportionally
Is Selleys 630 classified as Dangerous Goods for transport? → No — not classified for road, rail, sea (IMDG), or air (IATA) transport; no special documentation required

Overview: Selleys 630 Low Modulus Flexible Sealant

Selleys 630 Low Modulus Multipurpose Elastic Joint Sealant is a durable, flexible sealant suited to a wide range of general-purpose and professional sealing applications. Made by Selleys, a division of DuluxGroup Australia Pty Ltd, it comes in 300mL cartridges in three colours — grey, white, and black.

The defining characteristic of this product is its low modulus formulation. In sealant terms, modulus refers to the force required to stretch or compress a cured sealant to a given percentage of its original dimension. A low modulus sealant requires less force to deform, which means it handles significant joint movement — expansion, contraction, vibration, or settlement — without pulling away from the substrate or cracking. That's what separates a purpose-built elastic sealant from a standard filler or gap compound.

Selleys 630 cures through exposure to ambient humidity. Once applied, moisture in the surrounding air drives the curing process, converting the paste from its workable state into a flexible, rubber-like seal. No mixing, heating, or UV exposure required. This makes the product straightforward to use in most indoor and outdoor environments where atmospheric moisture is present.

How It Works: Humidity-Cure Elastomeric Chemistry

Understanding the curing mechanism helps you apply the product correctly and get the results you're after.

Selleys 630 is an elastomeric sealant — a category that includes silicone, polyurethane, and modified polymer sealants, all of which cure to a rubber-like elastic solid rather than a rigid mass. The humidity-cure, low-modulus behaviour is consistent with silicone or silyl-modified polymer (SMP/MS polymer) technology, both well-proven in this product class.

Humidity curing works like this: the sealant is packaged in a sealed cartridge to prevent premature exposure to moisture. Once dispensed, the outer surface of the bead begins reacting with water vapour in the air, and curing progresses from the outside inward. That means skin formation occurs relatively quickly on the exposed surface, while full through-cure takes longer and depends on bead thickness, ambient temperature, and relative humidity. Very dry conditions or enclosed spaces with minimal air circulation will slow the cure; higher humidity accelerates it.

Don't disturb the sealant bead after application, particularly before skin formation, as this undermines the integrity of the seal. Tooling — smoothing the bead with a wet finger or spatula — must be done promptly after application, before the surface begins to set.

Product Format and Specifications

Selleys 630 comes as a paste in a 300mL cartridge, the standard format for professional-grade sealants applied with a caulking gun. This gives you controlled dispensing, minimal waste, and the versatility to handle both large-scale and detailed work.

The three colour options — grey, white, and black — let you match the sealant to the surface:

White suits light-coloured surfaces such as painted walls, white-framed windows, and bathroom tiles.
Grey works on concrete, masonry, metal, and surfaces where a neutral tone fits.
Black suits dark substrates, rubber surrounds, or applications where a contrasting seal would look out of place.

On coverage: a 6mm-wide by 6mm-deep bead yields approximately 1.4 linear metres per 10mL of sealant, so a single 300mL cartridge covers roughly 42 linear metres at that bead size. Wider or deeper joints reduce coverage proportionally.

Applications and Suitable Substrates

Selleys 630 is formulated to bond and seal across a range of substrates rather than being built for a single material. The flexible, low-modulus cured sealant makes it the right choice for joints that experience movement.

Proven applications include:

Expansion and control joints in concrete and masonry, where thermal cycling causes regular dimensional change
Perimeter sealing around window and door frames, where the junction between frame and wall faces differential movement and weathering
Construction joints in cladding, curtain walling, and façade systems
General gap-filling and sealing in residential and light commercial settings

Compatible substrates include concrete, masonry, glass, aluminium, steel, and painted surfaces. That said, adhesion performance varies depending on surface preparation, contamination, and substrate porosity. Always check the manufacturer's technical data sheet for confirmed substrate compatibility and any required primers before use on critical or unusual substrates.

Application Guidance

The most common cause of sealant performance issues comes down to preparation and technique, not the product itself.

Surface Preparation

Surfaces must be clean, dry, and free of dust, grease, oil, loose material, and old sealant residue. Even a thin film of contamination prevents proper adhesion. For porous substrates such as concrete or masonry, make sure the surface is structurally sound — sealant applied over a friable or powdery surface will pull away from the substrate rather than holding across the joint faces.

Joint Design

For movement joints, design the joint so its width is at least twice its depth. This geometry ensures the sealant stretches across the joint faces rather than being pulled in three directions — a condition called three-sided adhesion, which restricts movement and leads to premature joint breakdown. Place a bond breaker tape or backer rod at the base of the joint before sealant application to prevent adhesion to the back of the joint.

Dispensing and Tooling

Load the cartridge into a standard caulking gun. Cut the nozzle tip to the desired bead width — a clean, angled cut at approximately 45° directs the bead precisely into the joint. Apply steady, even pressure as you draw the gun along the joint, filling it completely without air pockets.

Tool the bead immediately after application using a wet finger, a spatula, or a dedicated sealant tool. Tooling presses the sealant into contact with both joint faces, eliminates air pockets, and produces a smooth finish. Wetting the tool with water or a mild detergent solution stops the sealant from sticking during this step.

Curing and Overpainting

Allow the sealant to cure fully before exposing the joint to water, load, or movement. Paintability depends on the specific chemistry of the product — silicone-based sealants are generally not paintable, while polyurethane and SMP-based sealants accept paint once cured. Confirm paintability in the manufacturer's technical data sheet before applying any topcoat.

Safety Information

Selleys 630 carries a Hazardous classification under Safe Work Australia GHS 7 (the Globally Harmonised System of Classification and Labelling of Chemicals, 7th revision). The identified hazard is Eye Damage/Irritation — Category 2A, with hazard statement H319 (Causes serious eye irritation) and signal word WARNING.

Category 2A eye irritation means the product can cause significant but reversible irritation to the eyes on contact. It does not indicate a risk of permanent eye damage under the GHS classification system, but the irritation can be severe and demands prompt first aid.

Required Personal Protective Equipment (PPE)

PPE Item	Purpose
Safety glasses	Protect eyes from splashes or contact during application
Nitrile rubber gloves	Protect skin from prolonged or repeated contact
Overalls	Protect clothing and skin from incidental contact
Safety shoes	General worksite foot protection

Eyewash stations must be accessible at the workstation whenever Selleys 630 is in use. In the event of eye contact, immediately irrigate the eye with clean water for a sustained period — typically 15 minutes — and seek medical attention if irritation persists.

Transport Classification

Selleys 630 is not classified as Dangerous Goods for transport by road, rail, sea, or air under Australian, New Zealand, IMDG (International Maritime Dangerous Goods), or IATA (International Air Transport Association) regulations. It can be transported and shipped without the special handling, documentation, or vehicle requirements that apply to classified dangerous goods.

Ventilation

Work in a well-ventilated area when using any sealant or adhesive product. This minimises exposure to vapours released during application and curing.

Storage and Shelf Life

Because this is a humidity-cure product, keeping moisture out is the primary storage priority. Store cartridges in a cool, dry location away from direct sunlight and heat sources, upright where possible to prevent the paste from migrating toward the nozzle. After partial use, seal the nozzle with a purpose-made cartridge cap, a nail inserted into the tip, or a wrap of tape.

Properly resealed cartridges can often be used again. If a skin has formed at the tip, cut back the nozzle slightly to clear it. If curing has progressed further into the cartridge, discard it — using compromised product risks poor results.

Always observe the manufacturer-stated shelf life. Sealant used beyond that point can produce incomplete curing, reduced adhesion, or poor elasticity in the finished joint.

Practical Tips

Test adhesion on critical substrates first. Before committing to a large sealing job on an unusual or high-value substrate, apply a small test bead, let it cure fully, and check adhesion by attempting to peel it away. It takes minimal time and protects you from a costly re-do.
Bring cold cartridges to room temperature before use. Cold sealant is stiffer and harder to dispense evenly. Warming the cartridge first improves flow and gives you a neater, more controlled application.
Work in manageable sections. The tooling window is short once the sealant is dispensed. Apply a section, tool it immediately, then move on — rather than filling an entire long joint before going back.
Match the colour to the substrate. Where the sealant joint will be visible, a mismatched colour draws attention to it. Taking the time to choose the right shade is part of getting a professional finish.

References

Selleys 630 Low Modulus Safety Data Sheet — DuluxGroup / Selleys (Based on manufacturer SDS documentation provided)
Safe Work Australia — Globally Harmonised System of Classification and Labelling of Chemicals (GHS)
IATA Dangerous Goods Regulations — International Air Transport Association
IMDG Code — International Maritime Organization
DuluxGroup Australia — Selleys Brand

Frequently Asked Questions

What is the product name: Selleys 630 Low Modulus Multipurpose Elastic Joint Sealant

Who manufactures Selleys 630: Selleys, a division of DuluxGroup Australia Pty Ltd

What volume does each cartridge contain: 300mL

What colours is Selleys 630 available in: Grey, white, and black

Is white available: Yes

Is grey available: Yes

Is black available: Yes

What does low modulus mean: The sealant requires less force to stretch or compress

Why is low modulus important: It handles joint movement without cracking or pulling away

What type of sealant is Selleys 630: Elastomeric sealant

How does Selleys 630 cure: Through exposure to ambient humidity

Does it require mixing: No

Does it require heat to cure: No

Does it require UV exposure to cure: No

What drives the curing process: Water vapour in the surrounding air

Does curing progress from outside inward: Yes

What forms first during curing: A skin on the exposed surface

Does full through-cure take longer than skin formation: Yes

What slows the curing process: Very dry conditions or poor air circulation

What accelerates the curing process: Higher relative humidity

Can you tool the sealant after skin formation begins: No, tooling must be done before skin forms

What format is the product sold in: 300mL paste cartridge

What tool is required to dispense the product: A standard caulking gun

What is the approximate coverage at 6mm wide by 6mm deep bead: Approximately 42 linear metres per 300mL cartridge

How many linear metres per 10mL at 6mm x 6mm bead: Approximately 1.4 linear metres

Does bead width affect coverage: Yes, wider joints reduce coverage proportionally

Does bead depth affect coverage: Yes, deeper joints reduce coverage proportionally

Is Selleys 630 suitable for expansion joints: Yes

Is it suitable for perimeter sealing around windows: Yes

Is it suitable for perimeter sealing around door frames: Yes

Is it suitable for construction joints in cladding and façade systems: Yes

Is it suitable for general gap-filling in residential settings: Yes

Is it suitable for light commercial applications: Yes

Does it bond to concrete: Yes

Does it bond to masonry: Yes

Does it bond to glass: Yes

Does it bond to aluminium: Yes

Does it bond to steel: Yes

Does it bond to painted surfaces: Yes

Should adhesion be tested on unusual substrates: Yes, before committing to a large job

Must surfaces be clean before application: Yes

Must surfaces be dry before application: Yes

Must old sealant residue be removed before application: Yes

What is the minimum recommended joint width-to-depth ratio: Width must be at least twice the depth

What is three-sided adhesion: When sealant adheres to the back of the joint, restricting movement

Why is three-sided adhesion a problem: It restricts movement and causes premature joint breakdown

What prevents three-sided adhesion: A bond breaker tape or backer rod at the joint base

At what angle should the nozzle tip be cut: Approximately 45 degrees

How should the bead be tooled: With a wet finger, spatula, or dedicated sealant tool

Why is the tooling tool wetted: To prevent sealant from sticking during tooling

Is Selleys 630 paintable: Depends on the specific chemistry — confirm with the technical data sheet

Are silicone-based sealants generally paintable: No

Are polyurethane and SMP-based sealants paintable once cured: Yes

What is the hazard classification of Selleys 630: Hazardous under Safe Work Australia GHS 7

What eye hazard category is assigned: Eye Damage/Irritation Category 2A

What is the GHS hazard statement for eye irritation: H319 — Causes serious eye irritation

What is the GHS signal word for Selleys 630: WARNING

Does Category 2A indicate a risk of permanent eye damage: No, irritation is reversible under GHS classification

What eye PPE is required: Safety glasses

What hand PPE is required: Nitrile rubber gloves

What body PPE is required: Overalls

What foot PPE is required: Safety shoes

Must an eyewash station be accessible during use: Yes

How long should eyes be irrigated after contact: Typically 15 minutes with clean water

What should you do if eye irritation persists after rinsing: Seek medical attention

Is Selleys 630 classified as Dangerous Goods for road transport: No

Is Selleys 630 classified as Dangerous Goods for air transport: No

Is Selleys 630 classified as Dangerous Goods under IMDG for sea transport: No

Is Selleys 630 classified as Dangerous Goods under IATA regulations: No

Does transport require special documentation as Dangerous Goods: No

Should the product be stored in a cool, dry location: Yes

Should cartridges be stored away from direct sunlight: Yes

Should cartridges be stored upright: Yes

How should a partially used cartridge be resealed: With a cartridge cap, nail in the nozzle, or tape

Can a partially used cartridge be reused if properly resealed: Yes, often

What should you do if a skin has formed at the nozzle tip: Cut back the nozzle slightly to clear it

What should you do if curing has progressed further into the cartridge: Discard the cartridge

What happens if sealant is used beyond its shelf life: Incomplete curing, reduced adhesion, or poor elasticity

Should cold cartridges be warmed before use: Yes, bring to room temperature first

Why should cold cartridges be warmed: Cold sealant is stiffer and harder to dispense evenly

Should you apply sealant in manageable sections: Yes

Why work in manageable sections: The tooling window is short after dispensing

Where should the product be used regarding ventilation: In a well-ventilated area

What is the primary storage priority for this humidity-cure product: Keeping moisture out

Label Facts Summary

Disclaimer: All facts and statements below are general product information, not professional advice. Consult relevant experts for specific guidance.

Verified Label Facts

Product Name: Selleys 630 Low Modulus Multipurpose Elastic Joint Sealant
Manufacturer: Selleys, a division of DuluxGroup Australia Pty Ltd
Format: Paste in 300mL cartridge
Dispensing Tool Required: Standard caulking gun
Available Colours: Grey, white, and black
Curing Mechanism: Humidity-cure (ambient moisture/water vapour)
Mixing Required: No
Heat Required to Cure: No
UV Exposure Required to Cure: No
Curing Direction: Outside inward; skin formation precedes full through-cure
Approximate Coverage: ~1.4 linear metres per 10mL at 6mm wide × 6mm deep bead; ~42 linear metres per 300mL cartridge at that bead size
Coverage Variation: Wider or deeper joints reduce coverage proportionally
Hazard Classification: Hazardous — Safe Work Australia GHS 7
Eye Hazard Category: Eye Damage/Irritation — Category 2A
GHS Hazard Statement: H319 — Causes serious eye irritation
GHS Signal Word: WARNING
Permanent Eye Damage Risk (GHS): No — Category 2A irritation is classified as reversible
Required PPE — Eyes: Safety glasses
Required PPE — Hands: Nitrile rubber gloves
Required PPE — Body: Overalls
Required PPE — Feet: Safety shoes
Eyewash Station Required: Yes — must be accessible at the workstation during use
Eye Irrigation Duration (first aid): Typically 15 minutes with clean water
Dangerous Goods Classification — Road: Not classified
Dangerous Goods Classification — Rail: Not classified
Dangerous Goods Classification — Sea (IMDG): Not classified
Dangerous Goods Classification — Air (IATA): Not classified
Special Transport Documentation Required: No
Storage — Location: Cool, dry area away from direct sunlight and heat sources
Storage — Orientation: Upright where possible
Storage — Partial Use: Reseal nozzle with cartridge cap, nail, or tape to exclude moisture
Shelf Life Note: Use within manufacturer-stated shelf life; expired product may exhibit incomplete curing, reduced adhesion, or poor elasticity
Compatible Substrates (stated): Concrete, masonry, glass, aluminium, steel, painted surfaces
Stated Applications: Expansion and control joints, perimeter sealing around window and door frames, construction joints in cladding and façade systems, general gap-filling in residential and light commercial settings
Minimum Joint Width-to-Depth Ratio: Width must be at least twice the depth
Bond Breaker Required: Yes — bond breaker tape or backer rod at joint base to prevent three-sided adhesion
Nozzle Cut Angle: Approximately 45 degrees
Tooling Method: Wet finger, spatula, or dedicated sealant tool — must be completed before skin formation begins
Paintability: Depends on specific product chemistry — confirm with manufacturer's technical data sheet before applying topcoat

General Product Claims

Low modulus formulation handles significant joint movement — expansion, contraction, vibration, or settlement — without pulling away from the substrate or cracking
Described as a purpose-built elastic sealant, distinguished from standard fillers or gap compounds
Humidity-cure mechanism described as straightforward to use in most indoor and outdoor environments
Multipurpose designation indicates suitability across a range of substrates and applications rather than a single material
Colour options described as enabling a professional, matched finish on any surface
Warming cold cartridges to room temperature improves flow and dispensing control
Working in manageable sections recommended to stay within the tooling window
Adhesion testing on unusual or high-value substrates recommended before committing to a full job
Use of compromised (partially cured) product described as a risk to results quality
Well-ventilated working conditions recommended as standard practice during application and curing

Selleys 630 Low Modulus Multipurpose Elastic 07 product guide