Ready mixed filler vs powder: shrinkage and depth

You are in the aisle with a tub in one hand and a bag in the other. Ready mixed filler vs powder is not a brand contest. It is how the material sets, how deep you can go in one pass, and whether you will open the container again. Ready-mixed paste hardens as water leaves it, so one deep fill can shrink. Powder is mixed when you need it and sets chemically. Toupret UK, writing about its own range, describes powder as the low-shrinkage option with a shorter working time, and ready-mixed fills at about 10 mm, with fine smoothing at about 2 mm.

Products Compared kept eight amazon.co.uk surface fillers, checked on 15 October 2026. Every one is a ready-mixed paste, with no powder bag in the set. A hairline or a nick you will finish today is where that paste is the practical buy. A deep hole that shrinkage would reopen is where you look at powder, outside this comparison. We did not run a lab shrinkage test. Links to amazon.co.uk use the tag pcuk26-21. A qualifying purchase can earn a commission at no extra cost to you.

In short

For a hairline or a nick you will finish today, buy ready-mixed paste, which is the only type in the surface filler comparison. For a deep hole where drying shrinkage would reopen the repair, look at powder, which is not one of these eight listings. Paste layers are about 10 mm, then more after drying. Fine smoothing is thinner.

Ready-mixed paste dries as water leaves it

Ready-mixed filler arrives as a paste. You press it into the crack, and it hardens because water leaves it, into the air and into a porous wall. That drying is the whole set. A thick plug can pull back as it loses water, and the repair can open a hairline of its own a day later. Toupret states the point directly: ready-mixed paste shrinks as it dries. A shallow nick has little water to lose. A hole filled in one proud lump has more.

People still buy the tub because the job is usually that nick: picture hooks, a screw hole, a knock on a corner. The paste is already mixed, at a thickness you can knife on, without weighing powder. Working time is until the paste skins, not a chemical clock from the moment you add water. Replacing the lid lets you come back. Leaving it off is how the paste skins.

The limit is depth in one go. Treat a stated millimetre figure as a layer, not as a dare. If the paste sinks as it dries, the answer in these products is another layer after the first has dried, not a wetter mix and not a second brand stirred in. We are not giving a water ratio for reviving a tub that has already gone hard. That method was not in the datasheets we used.

Powder sets chemically and shrinks less

Powder filler is a dry mix you combine with water. Toupret describes it as setting chemically, with little shrinkage, and the same page does not put a depth limit on powder the way it does on ready-mixed paste. The trade-off it does name is practical: mixing is an extra step, and the working time is shorter. Once water is in the powder, you use that batch. You do not put the chemical set back in the bag.

Powder is the candidate for a deep hole, and the wrong fuss for three picture hooks. Toupret’s “no depth limit” line describes its own powder. It is not a licence to fill any cavity with any bag. We will not invent a brand, a scoop ratio, or a number of minutes.

Powder is the better fit when shrinkage would reopen the repair, and the worse fit for a hairline you can finish from a tub you already trust. The fine products in this set are ready-mixed pastes. A bag that says powder is a different purchase from those eight cards.

Depth: about 10 mm of paste, then another layer

Toupret puts ready-mixed fills at about 10 mm and fine smoothing at about 2 mm. Those are the manufacturer’s bands, and the kept listings sit near them. Palace’s ready-mixed data sheet, dated 28 October 2024, describes layers no thicker than 10 mm, then more after drying. Polycell’s multi-purpose page describes about 10 mm in one go for that ready-mixed product, again with further layers after drying. Palace’s 1 kg card, B07XMM93KC, repeats layers no thicker than 10 mm. It was £6.99 on 15 October 2026, with 4.5 from 4,537 reviews, and it is an interior paste.

Fine paste is the thinner job. Toupret’s about 2 mm is the smoothing band. Palace’s 600 g fine card, B07XGMLGRX, caps deeper repairs at layers of no more than 3 mm. Using that tub as a one-pass deep-hole filler is the mistake the comparison is written to stop. The paste may look filled at lunchtime and show a sink by the evening, because the water has left.

Build depth as layers, and let each one dry before the next. A hole that needs 15 mm is two campaigns with a multi-purpose paste that states 10 mm, not one heroic knife-load. Cold rooms and thick layers make a printed time a minimum. The Palace sheet’s full-cure note is at 20°C. We are not inventing a winter multiplier. If you need the clocks before you paint, they belong in how long to leave filler before painting.

The eight listings are all pastes

Every kept listing is ready-mixed paste. Palace fine, 600 g, and the Langlow two-pack of the same 600 g size, are the fine-surface end. Polycell’s 330 g tube, the Decex kit around a 396 g Polycell tube, Palace’s 1 kg tub, Sinto’s 5 kg pail, and the Zawan 1.4 kg kit are the larger pastes. FOME FLEX Finish is the lightweight putty aimed at plasterboard joints and screw holes. None of those cards is a bag of powder.

If your hole is a nick, stay inside this set and choose by depth, surface, and pack. Fine against multi-purpose is the versus page: fine or multi-purpose filler. Pack size, interior or exterior, and whether you will use the tub again sit on the buying guide. A 330 g tube will not cover a badly marked wall. A 5 kg pail is a loss if you only have three hooks, or if the lid arrives open.

Review counts are not a shrinkage test. Polycell’s 330 g tube showed 4.6 from 14,595 reviews. FOME FLEX showed 4.7 from six reviews marked as reviewed in Germany. Those are different kinds of evidence. Zawan’s file had no review line. Read the depth sentence on the card you buy. A high star rating on a fine paste does not turn it into a deep-hole filler.

When the hole is a deep gap, not a nick

A deep gap is a hole where one 10 mm layer will not meet the back, or where a single drying paste would have to shrink across a void. About 20 mm is deep-gap filler territory, and that product was not kept, so this page names no brand and no price for it. If the hole has no backing, the honest repair is often a patch, not a thicker paste. Plasterboard with a void behind the face is that case.

Use powder when you have decided the repair is deep, the edges are sound and dry, and you can mix and place a batch inside its working time. Use ready-mixed paste when the damage is shallow, you want to stop and start, and the tub states a depth that covers the nick in one or two layers. Gloss, dust, and damp bond poorly either way. Clean the hole before you commit to either material. A damp wall is a prior job, not a reason to switch from paste to powder.

The sources we used do not say you must mix the whole bag. Mixing is the extra step and the working time is shorter, so mix what you can place. Leftover wet mix is not a tub you recap for next month. Dry powder in a sealed bag is a different storage problem from paste that skins because the lid was loose.