A pug mill is a machine that mixes clay, compresses it and pushes it out as a dense, evenly moist log ready to use. De-airing models also pull a vacuum to remove trapped air. Studios mainly use pug mills to recycle scraps and trimmings into consistent, workable clay, saving hours of hand wedging and a lot of wasted material.
Walk into a busy ceramic studio and you’ll probably hear about reclaim before long. Every throwing session produces trimmings, slop and collapsed pots, and turning that mess back into usable clay is a constant job. In larger studios, a pug mill often does the heavy lifting.
At Le Studio Art Space in Mordialloc, clay preparation is part of everyday life in our ceramic studio, and pug mills come up whenever people talk about setting up their own space. This guide explains what a pug mill is, how it works, why studios use one, how it compares with hand wedging, whether it suits a small studio, and what it can’t fix.
What A Pug Mill Is
A pug mill is a machine designed to process clay. At its simplest, it takes clay in at one end, mixes it with rotating blades or augers, and pushes it out the other end as a compact, cylindrical log called a pug.
The name comes from pugging, an old term for working clay into a uniform, plastic state. Large pug mills have been used in brickworks and potteries for a very long time, while smaller versions suit studios and schools.
There are two main types. Standard pug mills mix and compress clay. De-airing pug mills add a vacuum chamber that pulls air out of the clay as it passes through, producing denser clay that’s often ready to use without further wedging.
Some modern machines also combine mixing and pugging, letting you add dry clay, water or reclaim and mix it to a set consistency before extruding. These are sometimes called mixer pug mills.
Pug mills come in a range of sizes, from compact benchtop units suited to individual potters to large floor machines in schools and production potteries. Several brands are available in Australia, including locally made options.
How A Pug Mill Works
You start by loading clay into the hopper at the top. This might be scraps, trimmings, softened reclaim or fresh clay that needs mixing.
Inside, a shaft fitted with angled blades or an auger turns slowly. It chops, mixes and pushes the clay forward, blending different moisture levels together.
In a de-airing model, the clay passes through a vacuum chamber. A pump removes air from the chamber, and the clay is shredded so trapped air can escape before it’s compressed again.
Finally, the clay is forced through a tapered barrel and out of a nozzle. The tapering compresses it into a dense log, which you cut to length with a wire.
Moisture control matters. If clay goes in too wet, it comes out too soft. Too dry, and the machine struggles. Many potters add a little water or blend wetter and drier clay to hit the right consistency. Our guide to signs clay is too wet or too dry helps you judge it.
Most pug mills are cleaned less often than you might expect. Many potters leave clay inside between sessions, sealing the nozzle so it stays moist, then clean thoroughly only when changing clay bodies.
Why Ceramic Studios Use A Pug Mill
Recycling clay is the biggest reason. Throwing and trimming generate a surprising amount of scrap, and without an efficient way to reclaim it, studios either waste clay or spend hours reprocessing it by hand. Our reclaim clay calculator shows how quickly scraps add up.
Consistency is another. A pug mill blends clay thoroughly, producing even moisture throughout. That consistency helps throwing, reduces cracking and makes results more predictable.
Saving time and effort matters too. Hand wedging large amounts of reclaim is physically demanding. A pug mill can process a large batch in the time it takes to wedge a few kilograms by hand.
Pug mills can also reduce strain on hands, wrists and backs, which is important for potters who work long hours or teach multiple classes a week.
For teaching studios, a pug mill helps manage the steady stream of reclaim from students, keeping clay available and costs down.
Some potters also use a pug mill to customise clay. Blending two compatible bodies, adding a little grog for texture, or softening a stiff batch can all be done in one pass. It’s worth testing any custom blend before committing a full kiln load, since even small changes can affect shrinkage and firing behaviour.
Pug Mill Versus Hand Wedging
Hand wedging is the traditional way to prepare clay. Methods like ram’s head and spiral wedging remove air and even out moisture, and they’re a core studio skill every potter learns. Our article on what a wedge tool does covers a related technique for cutting and checking clay.
A pug mill replaces much of the bulk preparation. It can handle large volumes, blend clay of different moisture levels, and produce dense logs quickly.
A de-airing pug mill often produces clay that can be used straight away for many purposes. However, many potters still give pugged clay a short wedge before throwing, both to align the clay particles and to feel its consistency.
Hand wedging also teaches you about clay. Feeling moisture, plasticity and air pockets through your hands builds understanding that a machine can’t give you.
Some tasks remain manual. Adding grog, mixing small test batches or wedging a single ball for throwing are often quicker by hand.
In practice, most studios that own a pug mill use both methods. The machine handles bulk reclaim and mixing, while potters wedge smaller amounts by hand before working.
Is A Pug Mill Right For A Small Studio
Cost is the first consideration. Pug mills are a significant investment, often costing more than a pottery wheel and sometimes more than a small kiln. Our pottery equipment cost calculator can help you weigh the numbers.
Space matters too. Even compact models need a sturdy bench or floor space, room to load and unload, and access to power. They’re heavy, so moving them around isn’t easy. You’ll also want a spot near a sink or reclaim area, since moving buckets of wet clay across a studio quickly gets tiresome.
Volume is the deciding factor for many. If you throw occasionally and produce small amounts of scrap, reclaiming by hand may be perfectly manageable. If you throw daily or teach, a pug mill can quickly pay for itself in time and clay.
Maintenance and cleaning take effort, especially when changing clay bodies, and noise can be a consideration in shared or home spaces.
Many potters choose to use a shared studio with a pug mill rather than buying one. Our article on buying a kiln versus using a community studio explores similar trade offs.
What Competing Pug Mill Guides Leave Out
Most pug mill guides focus on features and brands. They rarely mention how much reclaimed clay quality varies. Reclaim can include glaze contamination, plaster chips, dust or different clay bodies mixed together.
A pug mill blends whatever goes in. If plaster gets into reclaim, it can cause pieces to blow out or pop after firing. If different clay bodies are mixed, firing behaviour and colour may become unpredictable.
That’s why good studio habits matter. Keep reclaim buckets clearly labelled by clay body, avoid mixing in glaze slop, and keep plaster well away from reclaim areas. Our guide to what to do when clay dries out covers reclaim basics.
A pug mill also can’t fix clay that has gone sour, mouldy or contaminated, although mild odours from organic matter are common and usually harmless. It can’t restore plasticity lost to heavy contamination either.
Finally, it won’t replace good technique. Clay that’s pugged perfectly will still crack if it’s dried unevenly or fired too fast. Our ceramic studio and workshops and classes cover those skills alongside clay preparation.
Curious how a working studio keeps its clay in good shape? Come and see how clay is prepared, reclaimed and used in the ceramic studio at Le Studio Art Space in Mordialloc, and ask our makers how they manage reclaim.
Frequently Asked Questions
Do I need a pug mill to start pottery?
No. Most beginners never need one. Hand wedging and simple reclaim methods work well for small amounts of clay.
What is the difference between a pug mill and a de-airing pug mill?
A standard pug mill mixes and compresses clay. A de-airing pug mill also removes air using a vacuum, producing denser clay.
Can I skip wedging if I use a pug mill?
De-aired clay is often ready to use, but many potters still wedge briefly before throwing to check consistency and align the clay.
Can a pug mill mix different clay bodies?
It can physically, but mixing bodies can change firing behaviour. Most studios keep clay bodies separate and clean the machine between them.
Can I see a ceramic studio’s clay setup at Le Studio Art Space?
Le Studio Art Space’s ceramic studio welcomes visitors and new members. Ask about a visit to see how the studio manages clay, equipment and reclaim.
This article is provided for general educational purposes by Le Studio Art Space. Always follow the manufacturer’s operating and safety instructions for any clay processing equipment.