Pro Trade Gap Filler Smooth Finish

What is Selleys Pro Trade Gap Filler Smooth Finish, and where should you use it?

Selleys Pro Trade Gap Filler Smooth Finish is a white, paintable, flexible acrylic gap sealant suitable for interior and exterior applications. It uses a high-solids formula for low shrinkage and has a thick consistency optimised for smooth gunning — the trade characteristic that lets a long run of cornice or skirting be laid in one steady pass without the bead breaking up.

It skins in 20–30 minutes and is paintable in about 30 minutes, with excellent adhesion to timber, plasterboard, masonry and aluminium. Its movement capability is ±10%, so like the other Pro Trade acrylic filler it belongs in joints that move modestly rather than joints that move a lot.

Safety first: this product is a skin sensitiser

This is the most important thing on the page, and it comes from the product's Safety Data Sheet rather than its marketing. Pro Trade Gap Smooth Finish is classified as hazardous under Safe Work Australia GHS 7, with the signal word "Warning" and the hazard classification Sensitisation – Skin – Category 1. The hazard statement is H317: may cause an allergic skin reaction.

It contains the preservatives 5-chloro-2-methyl-4-isothiazolin-3-one (CMIT, CAS 26172-55-4) and 2-methyl-2H-isothiazol-3-one (MIT, CAS 2682-20-4), each at less than 0.05% w/w. A skin sensitiser is not the same as an irritant: the SDS notes that effects may be delayed, and that repeated or prolonged skin contact may lead to allergic contact dermatitis. Once sensitised, a person reacts on later exposures.

The practical consequence is that smoothing this product off with a bare wet finger — the standard technique with most acrylic gap fillers — is not what the manufacturer asks for. The SDS calls for protective gloves, protective clothing including eye/face protection, and a suitable respirator, and notes that nitrile rubber gloves are suggested as suitable for intermittent contact, with the user making the final assessment. Contaminated work clothing should not be allowed out of the workplace, and should be taken off and washed before reuse.

Other stated precautions: keep out of reach of children; read carefully and follow all instructions; avoid breathing dust, fume, gas, mist, vapours or spray. If it gets on skin, wash with plenty of water and soap; if skin irritation or rash occurs, get medical advice or attention.

It is not classified as Dangerous Goods for road, rail, sea or air transport, and it is a non-combustible material — although following evaporation of the water in it, residual material can burn if ignited.

Physical properties

Property	Value
Form	Paste
Colour	White
Odour	Characteristic
Solubility	Dispersible in water
Specific gravity	1.57
Viscosity	>21 mm²/s at 40°C
Flash point	Not applicable
Packaging	475 g cartridge (sold in 20-packs)

These are typical values from the product's Safety Data Sheet, which notes that they are typical values only and directs you to consult the specification sheet.

What the working times mean in practice

Skinning in 20–30 minutes is a generous window by trade standards, and it is what the "smooth finish" name is really about. Where a fast-skinning filler forces you to tool in short sections, this one lets you gun a longer run and then come back along it with a spatula or wet gloved finger. On a long cornice line, tooling in one continuous movement rather than in six-minute segments is what produces a joint without visible restart marks.

Paint-ready in about 30 minutes under standard conditions. The caveat Selleys attaches is worth reading before you commit a whole ceiling line: while the product is paintable with water- or oil-based paints, some water-based undercoats and flat paints may crack after drying, and testing is recommended. Flat and low-binder paints are the usual culprits — the film has less flexibility than a gloss and cannot follow a bead that is still shrinking underneath it.

Movement capability of ±10% is the design limit. Where a joint will move more than that, an acrylic filler of this type is the wrong choice regardless of how well it tools.

Where to use it

Suitable for interior and exterior use, on substrates such as:

• Wood
• Plasterboard
• Brick
• Glass
• Aluminium
• Ceramics
• Paintwork and many other building materials

How to apply it

Wear gloves, protective clothing and eye protection, and avoid inhaling dust or spray. Natural ventilation should be adequate under normal use conditions.

1. Clean the surfaces. Ensure the substrate is firm, dry and free of dust, grease and loose material.
2. Load the cartridge or tube and cut the nozzle to the required size.
3. Apply the bead into the gap or joint. Thicken as needed, but avoid overfilling.
4. Smooth or trowel the finish within the 20–30 minute skinning window.
5. Paint once it is paint-ready — about 30 minutes under standard conditions — with a water- or oil-based paint. For oil-based paint, confirm compatibility first.
6. Clean tools and excess material while wet, with water.

Limitations — where it should not be used

• Not suitable for joints expecting movement beyond ±10%.
• Although suitable for exterior use, performance depends on adequate paint-over and surface conditions. Exterior work needs to be coated.
• Substrate and paint selection may affect the final finish — some paints, particularly water-based undercoats and flat paints, may crack after drying. Test first.
• Avoid skin contact. The product is a Category 1 skin sensitiser and may cause an allergic skin reaction; effects may be delayed.

Clean up and storage

Clean tools and excess material with water while the product is still wet. Store in a cool, dry, well-ventilated place out of direct sunlight, away from foodstuffs, away from sources of heat and ignition, and away from oxidising agents. Keep the container standing upright and closed when not in use, and check regularly for spills. Dispose of contents and container in accordance with local, regional, national and international regulations.

For spills, wipe up small amounts with a clean rag or paper towel and seal in a properly labelled container. The material is slippery when spilt, so clean it up immediately.

First aid

The hazard classification, the composition and the protective equipment for this product are set out under Safety first above. What follows is what to do if something goes wrong anyway.

Exposure	What to do
Eyes	Wash out immediately with water, holding the eyelids open, and keep rinsing. In all cases of eye contamination it is a sensible precaution to seek medical advice.
Skin	Effects may be delayed. Remove contaminated clothing and flush the skin and hair with running water, then wash with soap. If swelling, redness, blistering or irritation occurs — including hours after the contact — seek medical assistance. A rash appearing late is the pattern that suggests sensitisation rather than simple irritation.
Inhalation	Move the person to fresh air, loosen tight clothing, keep them warm and at rest until recovered. Seek medical advice if effects persist.
Swallowed	Rinse the mouth with water. Do not induce vomiting. Give a glass of water to drink and seek medical advice. Never give anything by mouth to an unconscious person.

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 Pro Trade Gap Filler Smooth Finish

Can I smooth the bead with a bare finger?

The Safety Data Sheet asks for protective gloves — it classifies the product as a Category 1 skin sensitiser that may cause an allergic skin reaction. Nitrile gloves are suggested as suitable for intermittent contact.

How long do I have to tool it?

It skins in 20–30 minutes, which is a longer working window than the fast-skinning trade fillers and is what allows a smooth continuous finish on a long run.

How soon can I paint it?

It is paint-ready in about 30 minutes under standard conditions, with water- or oil-based paints.

Will the paint crack over it?

It can. Some water-based undercoats and flat paints may crack after drying — testing is recommended before you commit to a full run.

Can I use it outside?

Yes, it is suitable for interior and exterior use, though exterior performance depends on adequate paint-over and surface conditions.

How much movement will it take?

±10%. Beyond that, it is the wrong product for the joint.

What surfaces does it stick to?

Wood, plasterboard, masonry, brick, glass, aluminium, ceramics, paintwork and many other building materials.

Is it dangerous goods for transport?

No. It is not classified as Dangerous Goods for road and rail, marine or air transport.

Is it flammable?

It is a non-combustible material. However, once the water component has evaporated, residual material can burn if ignited.

What is in it?

The disclosed hazardous components are the preservatives CMIT and MIT, each at less than 0.05% w/w; the balance is ingredients determined to be non-hazardous or below reporting limits.

What size does it come in?

A 475 g cartridge, listed in the Safety Data Sheet as a 20-pack trade format.

How do I clean up?

With water, while the product is still wet.

If you need a faster paint-over, see Pro Trade Gap Filler Fast Skin, which skins in 6 minutes; for large cavities rather than joints, Pro Trade Expanding Foam. The full range is under gap fillers.