Feet, Bases, and Keeping a Box from Cracking as It Dries
Okay, so you've got a box now, or close to one. Walls joined at the corners, hopefully clean, hopefully scored and slipped because I don't budge on that. This lesson is about the part underneath, and it's not glamorous, but it's where a lot of boxes go wrong on their way to the kiln.
The base isn't just a floor
New handbuilders treat the base like an afterthought. Cut a flat slab, stick the walls on top, done. But the base is a join like any other join, and it's doing more work than the corner seams because it's carrying the weight of everything above it, plus it's usually the thickest single piece of clay in the whole form, which means it dries and shrinks at a different rate than your thinner walls.
That mismatch is where cracks start. Not always right away. Sometimes not until the kiln, which is the cruelest timing possible because now you can't fix it, you just get to find out.
Building the base right
If you're building the box on top of the base slab, here's the order I use:
- Cut your base slab a little bigger than you need. You'll trim it flush to the walls later, and it's much easier to trim excess than to patch a gap.
- Score the base where the walls will sit. Don't wait until the walls are up to think about this — mark the footprint with your template or the actual wall pieces before anything gets slipped.
- Score the bottom edge of each wall piece too. Slip both surfaces, press together, and run a small coil along the inside seam the way we did a few lessons back. That inside coil is doing real work here — it's reinforcing the longest, most stressed join in the whole piece.
- Once the walls are up and the seam is blended, flip your attention to trimming the base flush from the outside. A butter knife held at an angle against the wall works fine. You do not need a fancy tool for this.
If you're building the walls first and adding the base after — which some people prefer because it's easier to keep the walls square — same rules apply, just in reverse order. Score, slip, coil, blend. No shortcuts because the base is bottom-side and nobody will see it. Somebody will see it, eventually, when it cracks in half on the way out of the kiln.
Feet: do you need them?
You don't need feet on a box. A flat base sitting flush on a flat shelf is completely fine, and honestly it's the easier, more forgiving choice for your first several boxes.
But if you want to add feet — little coil or slab nubs at the corners that lift the box slightly off the table — they help in one real way: airflow. A box sitting flat on a slab has almost no air moving under it as it dries, and that bottom surface dries slower than everything else. Feet let air get underneath, which means the base dries closer to the same rate as the walls. Less mismatch, fewer cracks.
If you add feet, attach them the same way as everything else. Score, slip, small coil if it's a bigger foot. And keep them small and simple. This is not the place to get elaborate. I've seen people build ambitious little clawed feet on their first box and then wonder why the whole thing is lopsided three days later. Fix cracks, not personality — but also, don't invite trouble.
Drying a box without cracking it
This is the part where the dry air here actually works against you the whole time, and I will say this until it's annoying: cover it.
A box is more crack-prone while drying than a bowl or a cup because it has flat panels and sharp internal corners, and flat panels shrink unevenly if one side dries faster than another. The fix is slow, even drying, which means:
- Loose plastic over the whole thing for the first day or two, not tight against the clay, just draped so moisture isn't leaving in a hurry.
- Check it once a day. If the rim or corners look lighter and drier than the base, that's your cue to slow things down further — more plastic, less exposure, maybe move it somewhere without a heat vent blowing on it.
- Don't set it near a window with direct sun, and don't set it near the fireplace because you were trying to be efficient about the thermostat. I've made that particular mistake and it's not a shortcut, it's a countdown.
A story about restraint
I mention decoration less in box lessons because there's less flat real estate to ruin, but I'll tell you this one anyway. My daughter Olivia once took a finished vase of mine — already trimmed, already dried, sitting there waiting for glaze — and stamped a pattern into it with a Lego brick she found on the floor. She didn't ask. I came back into the room and there it was, decorated, without my permission, using a toy.
I was annoyed for about four seconds. Then I looked at it and it was better than whatever I'd been planning. Cleaner, more restrained, and genuinely more interesting than my original idea, which had probably involved too many stamps and not enough blank space.
Glaze less than you think you should, and decorate less than you think you should, is basically my whole philosophy, and an eight-year-old with a Lego brick proved it to me by accident.
Before next time
Get your base attached and your seams reinforced, feet or no feet, and get it under loose plastic before you do anything else today. Ten minutes of distraction is enough for the dry air here to skin over an edge and start you toward a crack you won't see until it's too late to fix.
~erin