What is Selleys No More Cracks Interior Powder Filler, and where should you use it?

Selleys No More Cracks Interior Powder Filler is a multipurpose powder filler for interior use on plaster, plasterboard, brick, masonry and wood. You mix it with water to a smooth paste, press it into cracks, dents and holes in walls and ceilings, and sand it back once dry. It withstands vibration and can be nailed and screwed once set.

The characteristic that decides whether it suits your job is the working time. Mixed filler stays workable for up to an hour, which is long by the standards of the category. That is what makes it a sensible choice for a room full of repairs: you can mix one batch and work your way around the walls rather than mixing repeatedly for each patch.

What the key numbers mean in practice

• Mix ratio: approximately 2½ parts powder to 1 part water, to a smooth paste.
• Workable for up to 60 minutes once mixed.
• Dry and paintable after 2–3 hours, depending on humidity.
• Sands easily to a smooth finish with fine sandpaper.

The hour of working time and the 2–3 hours of drying are separate clocks and it is worth keeping them apart. The hour is how long the paste in your bucket stays usable. The 2–3 hours is how long a fill in the wall takes before you can sand and paint it. Humidity extends the second one.

There is one warning attached to the working time that is easy to ignore and expensive to learn the hard way: contamination with dried product significantly reduces the working time and speeds up the drying time. In other words, mixing a fresh batch in a bucket with yesterday's dried filler stuck to the sides, or stirring with a crusty blade, seeds the new mix and it goes off early. Start with a clean bucket and clean tools every time. That is not fussiness — it is the difference between an hour of working time and considerably less.

Being able to nail and screw into it once dry is unusual for a wall filler and genuinely useful. If you have filled a damaged section of wall and later need a fixing in that area, this filler gives you something with substance to fix into.

Where to use it

It is a multipurpose interior filler, listed for:

• Plaster and plasterboard
• Brick and masonry
• Wood

It is designed to fill cracks, dents and holes in walls and ceilings. Its stated resistance to vibration suits it to the parts of a house that get knocked and shaken — walls near doorways, hallways and stairwells — where a brittle filler tends to loosen and drop out.

Selleys has a general walkthrough on how to fill cracks and dents in walls. If your repair is outdoors, use the Exterior Powder Filler instead — this one is for interior use only. The rest of the range is on the wall filler page.

How to apply it

1. Make sure the surface is clean, dry and free of loose material. On an old wall this usually means scraping back flaking paint or crumbling plaster around the crack until you reach sound material.
2. Mix approximately 2½ parts powder to 1 part water to form a smooth paste. Use a clean bucket and clean tools.
3. Use it within 60 minutes.
4. Press the filler firmly into the gap with a filling blade or scraper, and scrape off the excess as you go.
5. Allow 2–3 hours to dry, depending on humidity.
6. Sand with fine sandpaper to a smooth finish, then paint.

Pressing firmly is the part that gets skipped. A filler laid across the face of a crack rather than pushed into it has almost no depth holding it in, and it is the first thing to come away when the wall is knocked or sanded.

Limitations — where Interior Powder Filler should not be used

• For interior use only.
• Where movement occurs, use Selleys No More Gaps. The filler withstands vibration once set, but that is not the same as accommodating a joint that opens and closes. Cornice lines, skirting junctions and cracks that keep reappearing in the same place are movement, and they need a flexible product.

The distinction is worth getting right before you mix anything. A dent, a hole or a settled crack is a filling job. A joint between two building elements that move independently is a sealant job, and filling it will only buy you a few months.

Hazard classification

This filler is not classified as hazardous under Safe Work Australia GHS 7. It has no signal word and no hazard statements, it is not a scheduled poison, and it is not classified as Dangerous Goods for transport by road, rail, sea or air. Its composition is given as 100% ingredients determined to be non-hazardous or below reporting limits.

Do not carry that across to the exterior version. Selleys No More Cracks Exterior Powder Filler looks like the same kind of product — a grey powder you mix with water — but it contains 10–30% Portland cement and is classified with the signal word Danger, including H318: causes serious eye damage. The two products are mixed the same way and used with the same tools, so the habits transfer easily even though the hazards do not. If you are working with the exterior powder, read its own safety section.

For this interior filler the remaining precautions are the ordinary ones, and one of them is worth taking seriously because it is about dust rather than chemistry:

• Wear a dust mask while you tip and mix the dry powder, and again when you sand the set filler. Nuisance dust is still dust, and mixing a powder in a small room puts plenty of it in the air at head height.
• Eye protection while mixing. Dry powder is easily flicked up by a stirrer, and an eye full of any filler is an unpleasant afternoon.
• Wash the paste off skin with water before it sets, and wash your hands before eating, drinking or smoking.
• If any gets in an eye, wash it out immediately with water and seek medical advice if irritation persists.
• Keep it out of reach of children. Store the bag sealed in a cool, dry, well-ventilated place away from food.

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 No More Cracks Interior Powder Filler

How much water do I add?

Approximately 2½ parts powder to 1 part water, mixed to a smooth paste.

How long does the mixed filler stay usable?

Up to 60 minutes.

Why did my mix go off early?

Most likely contamination with dried product. Selleys warns that this significantly reduces working time and speeds up drying. Mix in a clean container with clean tools.

How long before I can paint?

2–3 hours, depending on humidity.

Can I use it outside?

No. It is for interior use only.

What surfaces can I use it on?

Plaster, plasterboard, brick, masonry and wood.

Can I nail or screw into it?

Yes, once dry.

Will it stand up to vibration?

Yes — it is described as withstanding vibration, which is why it suits walls that get knocked.

How do I sand it?

With fine sandpaper, once dry, to a smooth finish.

Can I use it where a crack keeps coming back?

A recurring crack usually means movement, and where movement occurs Selleys directs you to use No More Gaps rather than a filler.

Can I use it on ceilings?

Yes. It is designed for cracks, dents and holes in walls and ceilings.

Should I mix the whole bag at once?

Only if you can use it inside the hour. Mix to the size of the job in front of you.