I remember the first time I saw an open segmented bowl sitting on a display table at a local craft fair. It looked like a magic trick made of wood and negative space. Unlike a traditional solid bowl or even a standard closed segmented piece, this thing had tiny, intentional gaps between every single block of wood. It looked delicate, like a woven basket, but it was rock solid. I spent a good ten minutes just staring at it, trying to figure out how someone could possibly glue all those tiny pieces together without losing their mind.
If you're a woodturner, or even just someone who appreciates the craft, the transition from solid wood to segmented work is a big leap. But moving from closed segments to an open segmented bowl? That's a whole different ballgame. It's a test of patience, precision, and your ability to stay calm when you're "turning air."
Why bother with the gaps?
You might be wondering why anyone would go through the extra trouble. A closed segmented bowl is already a lot of work. You have to cut the angles perfectly so the ring closes without any visible glue lines. It's satisfying, sure, but the open style adds a layer of depth and lightness that you just can't get any other way.
When you build an open segmented bowl, you're playing with light. You can see through the walls of the vessel. It's less about the mass of the wood and more about the silhouette and the patterns created by the voids. It turns a heavy piece of timber into something that feels architectural. Plus, honestly, it's a bit of a flex. It shows you've mastered your jigs and your lathe technique to a point where you aren't afraid of a little "interrupted cut."
Getting the math right (without a headache)
I'm not a math guy. If you start talking to me about complex trigonometry, my eyes usually glaze over. However, you can't really wing it when you're making an open segmented bowl. Everything has to be calculated because if your gaps aren't uniform, the whole piece looks "off" once it starts spinning.
Most people use a "Wedgie Sled" or some kind of precision miter fence. The key is the number of segments per ring. Let's say you're doing 18 segments. In a closed bowl, those 18 pieces would touch and form a solid circle. In an open bowl, you're essentially cutting those same pieces but leaving a space—usually about half the width of a segment—between them.
The trick is using a specialized indexing plate on your lathe or a dedicated gluing jig. You aren't just gluing a ring together on the bench and then stacking it. You're often gluing the segments one by one onto the previous layer. It sounds tedious because it is, but it's the only way to ensure those vertical columns of wood line up perfectly.
Choosing the right wood
Not all wood is created equal for this kind of work. Because the contact points between the segments are so small, you need wood that glues well and doesn't splinter easily. I usually tell people to start with something stable like Maple, Walnut, or Cherry.
Maple is great because it's bright and shows off the gaps really well. Walnut provides that classic, rich look. If you want to get fancy, you can mix them. A dark Walnut segment followed by a bright Yellowheart or Bloodwood segment can create some stunning geometric patterns. Just be careful with oily exotic woods like Cocobolo or Teak; if you don't wipe the joints with acetone first, those tiny glue surfaces might fail. And in an open segmented bowl, a failed glue joint is a recipe for a very bad day at the lathe.
The "Sticking" point: Gluing it up
This is where the real work happens. Most turners use a "segment stomper" or a specialized press. You start with a solid base (the "feature ring" or just a solid puck of wood) and then you start building up.
You apply a tiny bit of glue to the bottom of a segment, place it down, and use a spacer to make sure the gap is exactly the same as the last one. Some guys use little plastic blocks; others use metal shims. It's a slow process. You're basically building a brick wall in a circle, but the bricks don't touch on the sides.
I've found that using a fast-setting wood glue or even a high-quality thick CA glue for positioning can save you hours. But if you're using PVA glue (the standard yellow stuff), you've got to give it time to tack up. If you rush it and the segments shift, your open segmented bowl will look like a leaning tower of Pisa once you start turning it down.
Turning air: The scary part
Once the glue is dry and you've got this "wooden cage" mounted on the lathe, it's time for the moment of truth. Turning an open segmented bowl is nothing like turning a solid bowl. When you turn a solid piece, the tool is always in contact with the wood. Here, the tool is hitting wood, then air, then wood, then air—maybe 24 or 36 times per rotation.
It makes a distinct whirr-whirr-whirr sound. It's intimidating. If you're not careful, the tool can catch in one of those gaps and blow the whole thing apart. The secret? Sharp tools and high speed. You want your bowl gouge or scraper to be razor-sharp so it slices through the wood fibers instead of grabbing them. You also want the lathe spinning fast enough that the tool "floats" across the gaps rather than dropping into them.
I always wear a full face shield. Not just safety glasses—a full shield. When a segment flies off at 1,000 RPM, it doesn't just fall; it becomes a projectile. But don't let that scare you. If your glue joints are solid and your cuts are light, it's surprisingly smooth.
Sanding and the finish line
Sanding an open segmented bowl is, frankly, a bit of a nightmare. You can't just hold a piece of sandpaper against the spinning bowl like you normally would. If you do, the edges of the segments will round over, or worse, the sandpaper will catch in a gap and yank your hand toward the spinning piece.
Most of the time, I end up doing a lot of power sanding with a small 2-inch disc while the lathe is off or spinning very slowly. You have to be meticulous. You also have to deal with the "inside" of the gaps. Some turners use small files or even strips of sandpaper glued to popsicle sticks to get inside those little windows. It's the "final 10%" of the work that takes 50% of the time.
For the finish, I usually go with a spray-on lacquer or a wipe-on poly. Trying to apply a friction polish or a heavy wax is tough because the gunk gets trapped in the openings. A few light coats of spray give it a nice, even sheen without filling in those beautiful gaps you worked so hard to create.
The payoff
When you finally take that open segmented bowl off the chuck and hold it up to the light, all that frustration disappears. There's something so satisfying about the way the shadows fall through the piece. It's light, it's intricate, and it's a conversation starter. People will pick it up and turn it over in their hands, asking, "How did you get the holes in there?"
You can tell them it's all about the math and the patience, but mostly, it's just about the love of the craft. It's not the fastest way to make a bowl, but it might just be the most rewarding. If you've been sticking to solid wood, maybe it's time to give the open style a shot. Just remember: keep your tools sharp and your glue joints clean. You'll do just fine.