Why Your Pugmill Clay Is Tearing (And How to Fix It)

If you’ve ever extruded a beautiful ribbon of clay from your pugmill, only to watch the edges start ripping and shredding a few feet in, you’re not alone. This is one of the most common pugmill complaints among potters especially for anyone new to working with a high-volume clay mixer for the first time.
A recent post in r/Pottery described exactly this scenario: clay extruding fine at first, then tearing at the edges. The potter tried adding water to fix it, which only made things worse. Here’s what’s actually going on, and how to get your clay (and your pugmill) back on track.
Why the Edges Tear
Torn or shredded edges on extruded clay almost always point to one thing: trapped air. A pugmill’s job is to mix and de-air clay as it pushes it through the barrel and out the die. If the clay isn’t fully de-aired or if it’s inconsistent in moisture from batch to batch — air pockets get squeezed and ripped open as the clay is forced through the die opening, especially on a narrow profile like a 2.5” x 0.5” ribbon.
Adding water seems like a reasonable fix when clay looks like it’s drying out, but more water at this stage usually makes tearing worse, not better. Wetter clay is stickier and shears more easily at the surface, and uneven moisture (wet pockets next to drier ones) creates exactly the kind of inconsistency that causes tearing in the first place.
How to Recondition the Clay
1. Stop adding water. Let the clay sit, wedged into a few large balls, in a sealed bag or under plastic for 24–48 hours. This gives moisture time to distribute evenly throughout the clay body instead of sitting in localized wet spots.
2. Wedge before you pug. Even with a pugmill, hand-wedging clay first breaks up large air pockets and creates more uniform moisture distribution, which makes a huge difference in how cleanly it extrudes.
3. Run clay through without the die first. Recycle it through the open barrel a few times to mix and de-air before attaching the die. Trying to extrude a precise profile while the clay is still inconsistent just multiplies the tearing.
4. Check your pugmill’s vacuum (if it has one). Many pugmills use a vacuum chamber to pull air out of the clay as it mixes. If the vacuum seal is weak or not engaged properly, de-airing won’t happen effectively no matter how many times you run clay through.
5. Go slow with a new mill. If you and the pugmill are both new to each other, run smaller batches at first. It’s easier to diagnose moisture and air issues in a few pounds of clay than in a few bags.
The Takeaway
Tearing is a symptom of trapped air and uneven moisture — not dryness. The fix isn’t more water; it’s patience, proper wedging, and giving the clay time to equalize before you ask it to extrude through a tight die. Once you dial in the right consistency for your specific clay body and machine, a pugmill becomes one of the most efficient tools in the studio for reclaiming and conditioning clay. Shop at our store today https://thekilnshop.com/product-category/pug-mills-clay-mixers/