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Summary: the interior of a ceramic covered jar lid must be precisely the same width as the opening of the jar. Learn how to measure a lid to a jar with tips from a master potter in this free ceramics video.
Jeff Zamek started making pots 36 years ago while working toward a business degree at Monmouth University. After which he went on to obtain B.F.A. and M.F.A. degrees in ceramics from...read more
"In making the lid, grip the piece lightly, with both hands, again, pushing down with your thumbs. Make a small hole, filling the hole with water and going down a little less than half inch from the bottom of the vat. With my thumbs, instead of going straight across, I will be starting at the bottom and then going slightly higher, as I get to the edge of the piece. That will form a slightly rounded bottom to the lid and, as you can see, the flange is already beginning to form. Using the other set of calipers, getting a reverse measurement, I'll have the outside diameter of the flange. At this point, it's fairly easy to move the flange out, if you have to, or in by pressing your right index finger in. You've made the shelf, you can move that in, supporting it with your left finger and then you can take another measurement. We can use a nice right angle to the rib to define that line, make a flat shelf but keep in mind, this lid is going to fit upside down on the bottom of the pot, on the pot."