Using Paper Joints for Turning Bowls
George VondriskaDescription
Turning bowls on a wood lathe is an absolute blast, and if you haven’t tried it, you are missing out big-time! Once you experience the beauty and satisfaction of bowl turning, you’ll be hooked. Like anything new that you try in the shop, however, there is a learning curve associated with turning bowls. One of the first things that you’ll need to learn is how to get the bowl blank mounted properly on the lathe so that you can work efficiently and safely through your turning project. It’s not difficult, but it needs to be done properly.
Once you have spent some time in your new hobby, you will likely want to add a four-jaw chuck to your arsenal, as one of the advantages that this brings is the ability to quickly mount the blank onto your lathe. Many beginning wood turners do not buy a four-jaw chuck immediately, however, and instead work with the standard-issue face plate that comes with most lathes. You don’t want to just screw the face plate directly to the bowl blank, however, because the screws will likely penetrate through the bottom of your bowl, which will cause you to turn a strainer rather than a bowl. Is there an inexpensive solution, you ask?
Create a paper joint. A paper joint is a temporary joint that attaches a sacrificial base to the bowl so that the screws will not penetrate into the bowl. The joint will hold the blank securely while you turn your project, and the temporary base is easily removed when the turning is complete.
Let it cure overnight. Because of the high force that will be placed on the paper joint from the spinning lathe and cutting pressure, be sure to allow the paper joint to cure overnight before using it.
When you're ready to turn bowls on your lathe, it's pretty natural to use a face plate to mount the blank. If we take that face plate and we screw it right to the back of the blank, we're gonna have a couple of issues. One, screw holes in the back of our material. Two, because the screws are running through the blank, it automatically limits the depth of the cut on the other side because you don't wanna hit the tips of those screws. So here's an alternative. We take a piece of scrap wood, which I've always called a dummy board that can be cut from anything. In this case, it's Oak veneered plywood. We glue that to the back of our blank. Now, when the bowl's all done, we don't want that to be part of the bowl, we wanna get rid of it. So we're gonna add one more element, and that's a piece of paper in between, it's called a paper joint. The paper is just grocery bag. I cut that out of this. The key to the paper is that it has to be porous so the glue can soak in from both sides. No shiny pages out of a magazine, that would not work for this. So big picture, here's how this comes together. On what will be the back of your bowl blank, we need to find the center. So I'm just going corner to corner, corner to corner. And we're gonna want to dimple that center. Now I'll do that with a scratch. All this will make sense in a moment. Standard yellow glue is all we need. And you do wanna make sure that we do both surfaces, being the back of the bowl and the front of the dummy board. Now you might've noticed there's a screw that's run through the dummy board, and it projects out the back. And remember, I put a dimple in there with the scratch hole. Well, this is where that's all gonna pay off. Let that screw pop through the paper. And then this is kind of the hardest part of the whole thing. Find that dimple. Clamp it. And anytime you're clamping stuff that you're gonna use on a lathe, do make sure you give it significantly adequate drying time. I always let these sit overnight. And at the risk of jinxing myself, I can tell you, I've never had a paper joint fail while I'm turning a bowl. We use this in my bowl turning classes as a technique all the time. I've never seen them come apart until we're ready to take them apart. That brings me to the next stage. This is how to put the paper joint together. Be sure to catch our other video clip, which is once the bowl's all done, how do we separate the paper joint?
New to the site. How do you access the next video to separate the joint?
I learned about this method in shop class in 1967. Works great.
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