What is Selleys Wet Area Matt White Silicone, and where should you use it?

Selleys Wet Area Matt Silicone is a 100% neutral cure silicone sealant with a matt white finish, made for bathrooms, kitchens and laundries. It delivers a waterproof, mould resistant seal that will not shrink, crack or peel away, and it is guaranteed for 25 years against cracking and peeling.

The reason to choose it over a standard white wet-area silicone is purely the finish. Matt tiles, matt benchtops and honed stone have become the default in modern bathrooms, and a glossy bead across a matt surface reads as an obvious line. This product is formulated to sit visually with those finishes rather than against them.

The constraint to settle before you buy it: it is not paintable, and painting must be completed seven days before the sealant goes on.

Technical specification

Property	Typical result
Technology	Neutral cure silicone
Colour	Matt white
Density	1.45
Shore A hardness	30
Elongation at break (ASTM D412)	450%
Service temperature	-40°C to 150°C
VOC content	Less than 50 g/L
Cure time	72 hours
Tooling window	5 to 10 minutes from application
Packaging	420g cartridge, matt white

These are indicative data only, not intended for the preparation of specifications. The low VOC figure meets Green Building Council of Australia limits for general purpose adhesives and sealants of less than 50 g/L.

What the key numbers mean in practice

There are two timings, and they do different jobs. The tooling window is 5 to 10 minutes from application — that is when the bead must be shaped and any masking tape removed. Selleys' own guidance is to work in sections that can be completed before skinning occurs, because tooling off and tape removal after the skin has formed produces a rough surface. On a matt finish that roughness is more visible than it would be on a gloss bead, since matt surfaces show texture rather than hiding it in reflection.

The cure time is 72 hours. That is the figure to plan the room around: the joint is not finished when it feels firm, and it should not be exposed to continuous water until it has fully cured.

Elongation at break of 450% with a Shore A hardness of 30 describes a soft, highly extensible seal — one that stretches as a bath fills and empties, or as a benchtop and splashback move relative to each other, without tearing away from either face. Neutral cure chemistry is what makes it non-corrosive, which is why the substrate list below includes copper, brass and metal fittings that an acetic cure silicone would attack.

A service temperature range of -40°C to 150°C covers everything a domestic wet area presents, including the hot end of a shower or a sink.

Where to use it

It is ideal for use on or around showers, baths, spas, plumbing fixtures and sinks. The stated material compatibility is:

• Ceramic, glazed and porcelain fixtures
• Metal, copper and brass fittings
• Powder coated aluminium and aluminium
• Plastic laminates
• Rubber
• Glass
• Stainless steel
• Concrete

The product page recommends it particularly for matt tiles and benchtops in bathrooms, kitchens and laundries, which is where the finish earns its keep.

Surface preparation

Surfaces must be clean, dry, and free of dirt, grease, oil or water. Clean the surface with turps and allow it to dry completely before you seal. Silicone will not bond reliably to a joint that is still damp or carrying soap residue, and in a wet area that residue is always present unless you remove it deliberately.

How to apply it

1. Clean and dry the joint area, wiping it out with turps and letting it dry completely.
2. Cut the nozzle at a 45 degree angle, cut the cartridge tip and fit the nozzle.
3. Place the cartridge in a caulking gun and apply with steady pressure, ensuring the sealant is pushed into the joint rather than laid across the surface.
4. Tool with a spatula dipped in detergent water within 5 to 10 minutes of application.
5. Remove any masking tape before the sealant skins. For neater joints, mask both sides before applying and pull the tape off early — tape removed after skinning drags the edge of the bead.
6. Clean up with turps before the product skins.
7. Allow 72 hours for the sealant to cure before exposing the joint to continuous water.

Limitations — where Wet Area Matt Silicone should not be used

These are the manufacturer's stated limits:

• Not paintable. Complete painting seven days before applying the sealant.
• Not suitable for use on PP, PE or PTFE.
• Not suitable for aquariums.
• Not suitable for food or drinking water contact.
• Not suitable for permanent water immersion. It is a wet-area sealant, not an underwater one.

The product page adds that it is not suitable for materials that bleed oils or solvents.

The food and drinking water exclusion is the one that surprises people, because the product is recommended around sinks. Sealing the joint behind a sink is within its use; a surface in direct contact with food or potable water is not.

Clean up, maintenance and storage

Uncured product may be removed with mineral turpentine. Cured product can be removed with Selleys Sealant Remover or by cutting and scraping.

The one maintenance instruction Selleys gives is that the sealant must be cleaned regularly to avoid build-up of soap scum. That deposit is what mould feeds on, and it accumulates fastest at the base of a shower wall where water and residue collect. Wiping the bead down as part of normal cleaning is what keeps the joint looking and performing as it should.

Store in a dry place below 30°C, and use within 6 months of opening.

The 25-year guarantee

The guarantee applies when the product is used as directed, for private use, and within 12 months of purchase, and covers the product against crumbling, cracking or peeling away. If it does not perform as specified within the warranty period, Selleys will replace the goods free of charge; to claim, contact Selleys with details of the claim, show proof of purchase and bear the expenses incurred in making it. These benefits are in addition to rights and remedies under Australian Consumer Law, which cannot be excluded.

Hazard classification

Classified as hazardous under Safe Work Australia GHS 7, with the signal word Warning.

• Skin sensitisation — Category 1. H317: may cause an allergic skin reaction.
• Eye irritation — Category 2A. H319: causes serious eye irritation.
• Flammable liquids — Category 4. H227: combustible liquid.

It is not classified as Dangerous Goods under the Australian Code for the Transport of Dangerous Goods by Road & Rail, or under New Zealand NZS5433. It is, however, classified as a C2 combustible liquid for the purposes of storage and handling under AS 1940, and state regulations should be consulted for specific storage requirements.

What is in it

Chemical entity	CAS number	Proportion (w/w)
2-Butanone, O,O',O"-(methylsilylidyne)trioxime	22984-54-9	1–10%
2-Butanone, O,O',O"-(ethenylsilylidyne)trioxime	2224-33-1	1–10%
N-[3-(Trimethoxysilyl)propyl]ethylenediamine	1760-24-3	1–10%
Ingredients determined to be non-hazardous or below reporting limits	—	Balance

The two butanone-oxime silanes at the top of the table are the neutral cure system. They react with moisture in the air and release methyl ethyl ketoxime rather than acetic acid, which is why this sealant does not smell of vinegar and does not attack the metals and masonry that an acetic-cure silicone attacks. That is the same choice of chemistry the page above describes for the finish; it is also the reason the eye classification here is Category 2A irritation rather than the Category 1 eye damage carried by the acetic-cure wet-area products such as Fix & Go Bathroom & Kitchen and White For Life. Neutral cure is the gentler chemistry on both your fittings and your eyes.

What it gives up is on the skin side. Category 1 skin sensitisation is the classification to take seriously, and it is not the same thing as irritation. An irritant reddens the skin while it is in contact and settles once you wash it off. A sensitiser teaches the immune system to react: once that has happened it is generally permanent, it is triggered thereafter by much smaller exposures than the one that caused it, and each later contact tends to be worse rather than milder. It develops from repeated ordinary contact rather than one dramatic exposure — which is exactly what smoothing a bead with a wet fingertip, bathroom after bathroom, amounts to. Tool with a tool, or with a soapy finger inside a glove.

H227 combustible liquid is the mildest flammability class there is: the material will burn if you set fire to it, but it is not a flammable liquid in the sense that a solvent-borne product is, and it is undeclared for transport. The AS 1940 C2 label is a storage-quantity matter and will only bite if you are holding real volume — a trade store room rather than a shelf in a van.

All of this belongs to the uncured material. Once the bead has cured it is inert, and the practical consequence is simply that the hazard window is the day you do the work, not the twenty-five years afterwards.

Protection

• Gloves — the important one, given the sensitisation classification. Nitrile rubber is indicated as suitable for intermittent contact; glove construction and site conditions vary, so make the final assessment yourself.
• Eye protection — safety glasses; protective clothing including eye and face protection is specified for normal handling.
• Clothing — overalls and safety shoes in a workplace setting.
• Ventilation — natural ventilation is adequate in normal use, but work the room well ventilated and avoid breathing vapours or spray. Do not eat, drink or smoke while using it.
• Wash hands before smoking, eating, drinking or using the toilet, and wash contaminated clothing before storing or re-using it.
• Storage — cool, dry, well-ventilated place out of direct sunlight, away from foodstuffs, incompatible materials and sources of heat or ignition. The page above adds: below 30°C, and use within 6 months of opening.

First aid

Exposure	What to do
Skin	Immediately remove contaminated clothing and flush the skin and hair with running water. Keep flushing until the Poisons Information Centre or a doctor tells you to stop, or for 15 minutes, then get to a doctor or hospital. For gross contamination, drench immediately with water and remove clothing. If skin irritation or a rash occurs, get medical advice or attention — including when it appears some hours later, which is the pattern of an allergic reaction rather than simple irritation.
Eyes	Rinse cautiously with water for several minutes. Remove contact lenses if present and easy to do, then keep rinsing. If eye irritation persists, get medical advice or attention.
Inhalation	Move the person to fresh air without becoming a casualty yourself. Remove contaminated clothing and loosen the rest, let them settle into the most comfortable position and keep them warm and at rest until fully recovered. Seek medical advice if effects persist.
Swallowed	Rinse the mouth with water. Do not induce vomiting. Give a glass of water to drink. Never give anything by mouth to an unconscious person. If vomiting occurs, give further water and seek medical advice.

If poisoning occurs, contact a doctor or the Poisons Information Centre — 131 126 in Australia, 0800 764 766 in New Zealand — with the container to hand. Selleys emergency line: 1800 220 770 in Australia, 0800 220 770 in New Zealand.

Common questions about Selleys Wet Area Matt White Silicone

How long do I have to tool the bead?

5 to 10 minutes from application, using a spatula dipped in detergent water. Tape must also come off inside that window.

How long does it take to cure?

72 hours. Allow the full cure before exposing the joint to continuous water.

Can I paint over it?

No. It is not paintable — complete any painting seven days before applying the sealant.

Will it corrode brass or copper fittings?

No. It is a neutral cure silicone, and copper and brass fittings are on the list of materials it works on, along with metal, powder coated aluminium and stainless steel.

Will it stick to plastic?

Plastic laminates are listed as suitable. It is not suitable for use on PP, PE or PTFE.

Can I use it around a kitchen sink where food is prepared?

It is suitable for sealing around sinks, but it is not suitable for food or drinking water contact.

Can I use it in a fish tank or a pond?

No. It is not suitable for aquariums, and not suitable for permanent water immersion.

Will it hold up on a bath that moves when it fills?

Elongation at break is 450% with a Shore A hardness of 30, so the cured bead is soft and highly extensible. A bead with real depth in the joint will accommodate that movement better than a thin surface smear.

How do I stop it going mouldy?

Clean the sealant regularly to avoid a build-up of soap scum, which is what supports mould growth on the surface of a bead.

How do I remove cured sealant?

With Selleys Sealant Remover, or by cutting and scraping.

How long can I keep an opened cartridge?

Use within 6 months of opening, stored in a dry place below 30°C.

What if I want a gloss finish instead?

Compare the options across the wet area silicone range, or read the background on the Selleys Wet Area Silicone range.