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Cottonwood Bowl

by Richard Gaskell - In 2009 I got a large chunk of wet cottonwood to turn. Wet wood will ooze water and when the piece of wood is turning, that water sprays everywhere. I had to make a tent of plastic sheeting to keep the rest of the shop dry.

This is going to be the bottom of the bowl. I'm doing "out-board" turning where the headstock is turned so the work hangs over the floor because it is just too big to turn over the bed of the lathe. Notice the hardwood board I use to prop up the toolrest and the 2x4 to steady the lathe.

Here I've started turning the bottom down until I have no more bark. I'll need to make a spigot for the chuck to hold while I turn the top and inside of the bowl.

The wood shavings come off in long, wet ribbons. When you have a continuous cut it shoots across the enclosure like streamers. In the picture below you can see I've got down to solid wood and am starting to make the spigot.

I've finished shaping the bottom and rounded the sides at the top of the bowl. My plan is to roll the edges in at the top because I like bowls that enclose the contents. The chuck is on the spigot and I'm ready to work on the top.

I've been turning at a slow speed because the wood is so unbalanced. My first job is to take off the extra wood so I can start shaping and hollowing out the bowl. In the picture below you can see the edge closest to the camera slopes back quite a bit so I'm going to have to cut all of the sides down to match that.

We're now round and it's time to start shaping. In the picture below, I've got the bowl so that I have solid wood all around. I'm going to do some shaping because right now the bowl looks too squatty and I prefer rounder sides. I want to make the sides quite thin so I'm going to have to work quickly because the wood will start to dry out and change shape.

I've got the outside shape the way I want it and now I'm working on the inside. I take a light and shine it close the the wall. The wood, being so wet, is translucent and you can tell how thick the wood is by the colour. If it's red/orange, you're fine but if it's white, you've cut too far! I have to undercut the top part of the inside. Thrilling stuff because if the bowl dries out too quickly it will crack or warp and you've just made your bowl into firewood.

The large cone in the middle is to keep as much mass in the middle of the bowl for as long as possible to add stability. It gets in the way, though so I have to cut it down as I go. 

Now the walls are done, the middle mass is gone and I'm shaping the round-out to the bottom of the bowl. I have to work quickly because you can already see how the edge of the bowl is starting to warp. I'm planning to dry the bowl in the microwave to reduce the chance of cracking but I need to finish first!

Below is the nearly finished bowl. I love the thinness of the sides and the figuring is spectacular but will really show up once oiled. Now comes the scary part - I have to turn the bowl around again and use a chuck to hold the rim of the bowl so I can finish the bottom of the bowl. If it dries too much or I put too much stress on the rim, the bowl will be ruined.

I have to take the spigot off without going through the bottom of the bowl. Gently does it!

The finished bowl after being dried in the microwave and oiled. It warped even more but most of the movement took place while it was steaming in the microwave so it warped rather than cracking.

 

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