Sunday, September 10, 2017

Ball Opener

picking out PVC pipe fittings

I made and started using this new tool, called a "ball opener" last month. I didn't know anything about the tool until I watched this Tom Whitaker video on YouTube:

The tool looked easy to make and I thought it might help some of my students, so I gave it a shot. 

my CPVC ball opener

In the video, Whitaker talks about using CPVC. I had some initial trouble finding the parts so I picked up PVC pipe and fittings. Then I found the CPVC and decided to make a version from both materials. The PVC is a little thicker and I was able to find a cross shaped center piece with four openings. The CPVC is thinner (though they are both labeled as the same size) and I only found a t-shaped center.

my double-ended PVC ball opener

Putting together the tool was really simple. I used a mitre box to cut the pipe and my husband had some primer and cement to attach the pieces. I made a mess with the primer, but the whole process was fast and easy.

adding water to the hole I started with the ball opener

The ball opener is designed to be inserted into a centered ball of clay on the wheel. The tool is pressed straight down in the center of the clay. Because the center pipe is slightly shorter than the side pipes, it will not hit the wheel head, but will leave a 1/4" or 1/2" floor in the clay. Then the tool can be pulled towards the body, opening up the ball of clay and leaving a flat floor.

opening out the floor with the ball opener

In the video, Whitaker suggests that using the tool is simple, which is true, and that the tool doesn't bounce around at all. I found that the tool did bounce, but I suspect some practice on my part will help with that. In my initial test of the tool, I only used it for roughly 15 pieces.

pulling the walls up with the ball opener in the reclaim bucket

Initially, I thought this might be an acceptable tool for beginning students. I figured it wasn't really necessary for me because I know how to throw. What surprised me is that it immediately improved my results. Out of 15 pieces I threw with this tool, 15 dried and fired through the bisque with no cracks in the floor. Without the tool I don't lose much, but I probably lose 10% to small s-cracks in the floor. 

oops, my recycled clay had some junk in it

I used both tools and both ends, which means that some of my floors were closer to 1/2" with a 1/4" wall, but still, no cracks. I even threw with some reclaim clay with no cracking. Additionally, throwing with this tool was faster. Usually it takes me longer to drill the hole, open the floor, and compress the floor. These steps were rolled into one fast step with the ball opener. 

feet with not cracks

The results were pleasing. I think I may make a dozen or so more of these tools to take to school. They won't work for bowls with rounded bottoms, but they might be a relief for students making cylinders. Students should probably still learn the old-fashioned way, but this is such a simple tool they could make one themselves for use after YVC.

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