What is Selleys Spakfilla Rapid, and where should you use it?

Selleys Spakfilla Rapid is a ready-mixed, lightweight, fast-drying filler that is virtually non-shrinking and non-cracking, and needs only one application. It is white, water based, and its headline feature is the one in the name: a thin fill can be painted in 30 minutes.

That speed is the reason to choose it, and the qualifier attached to it is the reason to read the rest of this page. Thirty minutes applies to applications less than 2 mm thick, painted with water-based paints. Anything more than 2 mm takes 24 hours. There is no gentle gradient between those two figures — going a little deeper costs you the day, so it pays to keep fills genuinely thin.

Technical specification

Property	Typical result
Technology	Water based
Appearance	Smooth paste
Colour	White
Sand / paint time — less than 2 mm	30 minutes
Sand / paint time — more than 2 mm	24 hours
Packaging	180 g and 260 g tubs
Use	Interior and exterior
Minimum temperature	5°C

These are indicative data from the product's technical data sheet only, and are not intended for the preparation of specifications.

What the key numbers mean in practice

The 30 minute figure changes how a job is sequenced. On a conventional filler you fill everything, leave it, and come back hours later to sand and paint. With Spakfilla Rapid, filling a room's worth of picture hook holes and small dents and then painting the same wall in one visit is realistic. That is the whole value proposition.

The 24 hour figure is the boundary of that promise. More than 2 mm deep and you are on a full day's wait. So is anyone painting with oil based paint: Selleys states to allow 24 hours before painting with oil based paints, regardless of depth.

Two conditions extend the times further: cold and humid weather. In an unheated room in winter, 30 minutes is optimistic.

Virtually no shrinkage means no overfilling and minimal sanding. That is not just a convenience claim — on a lightweight filler, heavy sanding is genuinely risky, because the filler is softer than the plasterboard face around it and you can dish the repair or cut through the paper. A flush, smoothed-off fill that needs only a light sand is the intended result.

The technical data sheet also lists Spakfilla Rapid as moisture and mould resistant, which is unusual in a lightweight interior filler and part of why it is rated for exterior use as well.

Where to use it

It is suitable for filling:

• Wallboard
• Wood
• Masonry
• Plaster
• Plasterboard
• Primed nail heads

It is rated for interior and exterior use. Outside, protect the repair from rain until it is dry and painted over with two coats of paint — the paint system is what weatherproofs the repair.

The two pack sizes suit different jobs: the 180 g tub for a handful of repairs, the 260 g tub for a room. For jobs needing substantial filling on tougher substrates, see Spakfilla Heavy Duty; if you would rather have the filler tell you when it is dry, Spakfilla Coloursmart goes on pink and dries off-white. The full range is on the wall filler page.

How to apply it

1. Prepare the surface. It must be clean, dry and free of loose or protruding material — sand lightly if necessary.
2. Using the spatula provided, press the filler firmly into the hole or crack and smooth it off. There is no need to overfill: it exhibits virtually no shrinking.
3. Wait until it is completely set — 30 minutes in thin applications.
4. Sand lightly, if necessary, before painting with water-based paints. Minimal sanding is required for a smooth finish.
5. Clean the dust and loose filler particles off before painting, using Selleys Sugar Soap or Selleys Super Kleen.
6. For oil based paints, allow 24 hours before painting.
7. Outside, protect the repair from rain until dry and painted over with two coats of paint.

Step 5 is the one most people skip, and it is the reason a fast repair sometimes looks poor after painting. Sanding leaves fine dust across the wall; paint applied over that dust does not adhere properly and the repair reads differently to the surface around it. Cleaning takes a minute and it is the difference between a 30 minute repair that disappears and one that shows.

One more thing to expect: some paints may temporarily discolour when applied over the filler, but will revert to the correct colour once dry. If the first coat looks off over your repairs, wait for it to dry before doing anything about it.

Reviving a stiff tub

If the filler has stiffened before use, stir it with a spatula. If it is still too dry, add one teaspoon of water and stir again to the consistency you want. Product that has actually hardened should be discarded.

Limitations — where Spakfilla Rapid should not be used

These are the manufacturer's stated limits:

• Do not use on plastic, metal, or exterior timber likely to swell or shrink on absorption of water.
• Avoid using below 5°C or in wet conditions.
• Do not nail.
• Do not use where load or compression occurs, as the product may be crushed — Selleys gives the example of behind a door, where the knob touches against the wall.
• Where movement occurs, use Selleys No More Gaps.

The door knob example is worth dwelling on, because that dent in the wall behind a door handle is one of the most common repairs anyone makes, and it is explicitly the wrong job for this filler. A lightweight filler will be crushed by the same impact that made the mark, and the repair will fail the first time the door swings hard. Fixing the cause — a door stop or a knob buffer — is part of the repair, not an optional extra.

Clean up and storage

Clean up: uncured product can be removed with water, and application tools may be cleaned with water. Cured product has to be removed by scraping or sanding.

Storage: keep the container closed when not in use. With a ready-mixed water based filler, an open or poorly sealed lid is what produces the hardened, unusable product described above.

Hazard classification

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

• Sensitisation — Skin — Category 1. H317: may cause an allergic skin reaction.
• Eye irritation — Category 2A. H319: causes serious eye irritation.

It is not classified as Dangerous Goods under the Australian Code for the Transport of Dangerous Goods by Road & Rail or New Zealand NZS5433.

What is in it

Chemical entity	CAS number	Proportion (w/w)
Alcohols, C12–C14, ethoxylated, sulfates, sodium salts	68891-38-3	1–10%
2-Octyl-2H-isothiazol-3-one (OIT)	26530-20-1	<0.1%
1,2-Benzisothiazol-3(2H)-one (BIT)	2634-33-5	<0.05%
5-Chloro-2-methyl-4-isothiazolin-3-one (CMIT)	26172-55-4	<0.05%
2-Methyl-2H-isothiazol-3-one (MIT)	2682-20-4	<0.05%
Ingredients determined to be non-hazardous or below reporting limits	—	Balance

The product is mostly water, fillers and binder. The surfactant at 1–10% is a sodium alkyl ether sulfate, the family used in detergents and shampoos and a chemical class associated with eye irritation; the four entries below 0.1% are isothiazolinone preservatives, the family associated with skin sensitisation in water-based products. The SDS does not attribute either classification to a named ingredient, so this page offers those connections as chemistry rather than as sourced fact.

The speed of this filler is what makes the skin classification worth reading. A thin fill is paintable in thirty minutes, which is exactly why it gets used for quick jobs done bare-handed — a finger in the tub, a smear into the hole, a wipe on a rag. Sensitisation is not irritation: it is the immune system learning to react to the material, it is generally permanent once acquired, it is triggered thereafter by much smaller exposures, and it is built from repeated casual contact rather than from one bad incident. A fast product invites the repetition.

H319 — serious eye irritation — matters most when you are filling or sanding above head height, which is most of what a wall and ceiling filler gets used for. The same applies to reviving a stiffened tub with a teaspoon of water: stirring it back to consistency is prolonged hand contact, and it is easy to rub an eye afterwards without thinking.

Protection

• Eye protection — safety glasses, particularly for overhead filling and for sanding.
• Gloves — nitrile rubber, suitable for intermittent contact per the SDS, with the user making the final assessment.
• Dust mask — when sanding the dried filler.
• Ventilation — natural ventilation is adequate under normal use conditions; keep air circulating in the room you are working in.
• Wash hands before eating, drinking or smoking. Wash contaminated clothing and protective equipment before storing or reusing.

First aid

Exposure	What to do
Eyes	Rinse cautiously with water for several minutes, holding the eyelids open. Remove contact lenses if present and easy to do, then keep rinsing. If eye irritation persists, get medical advice or attention.
Skin	Remove contaminated clothing and wash with plenty of water and soap. If a rash or irritation develops, including hours later, get medical advice or attention.
Inhalation	Move the person to fresh air, 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 Selleys Spakfilla Rapid

Can I really paint it in 30 minutes?

For applications less than 2 mm, with water-based paints, yes — once it is completely set. Deeper fills take 24 hours, and so do oil based paints.

How long does a deeper fill take?

More than 2 mm: 24 hours.

Does cold or humid weather change that?

Yes. Expect longer drying times in cold or humid conditions.

Do I need to overfill?

No. It exhibits virtually no shrinking, so press it in and smooth it off.

How much sanding will it need?

Minimal — a light sand if necessary once it is completely set.

What sizes does it come in?

180 g and 260 g tubs.

What surfaces can I use it on?

Wallboard, wood, masonry, plaster, plasterboard and primed nail heads.

Can I use it outside?

Yes. Protect the repair from rain until it is dry and painted over with two coats of paint.

Can I use it on plastic or metal?

No. Do not use it on plastic, metal, or exterior timber likely to swell or shrink with water absorption.

Can I fill the dent behind my door where the knob hits the wall?

No. That is a compression point, and Selleys specifically names it: do not use where load or compression occurs, as the product may be crushed.

Can I nail into it?

No. Do not nail.

Do I need to clean the wall before painting?

Yes. Clean the dust and loose filler particles off using Selleys Sugar Soap or Selleys Super Kleen, so the paint adheres properly.

My paint looks discoloured over the repair. Is that a problem?

Some paints temporarily discolour over the filler and revert to the correct colour once dry.

The tub has stiffened. Can I still use it?

Stir it, and add one teaspoon of water if it is still too dry. Discard it if it has actually hardened.

How do I clean up?

Water while the product is uncured, including for tools. Cured product comes off by scraping or sanding.