Gwendeanne Posted July 14, 2011 Report Share Posted July 14, 2011 I don't remember my HS geometry. Does anyone have any websites or books they use to make pottery shapes. For instance, right now I'd like to find the center of my dome shaped plaster mold. I googled it without success. I'm also trying to make a roof from slabs, but would love a formula for a pyramid type shape. I use cardboard before I cut the slabs, but still need help with the shape for that. How does everyone figure these things out, do you get any assistance online? Link to comment Share on other sites More sharing options...
Marcia Selsor Posted July 14, 2011 Report Share Posted July 14, 2011 I just use a tape measure. For instance, a pyramid has four equal sides. Maybe look up an old solid geometry book. I really loved my Geometry class and I enjoy making tools for helping me building forms. You can see my articles like Right Angle Jig or Over the Hump in the archives of Ceramics Arts Daily. Marcia Link to comment Share on other sites More sharing options...
bciskepottery Posted July 15, 2011 Report Share Posted July 15, 2011 For your plaster mold, place the mold on some newsprint. Trace the circumfrence of the mold onto the newsprint, maybe using a compass to make the circle about an inch larger. Move the mold off the newsprint. Fold the newsprint circle in half, then again into quarters. Unfold and center the mold back on the newsprint. Connect the corners of the fold with the corner opposite. Where the two lines intersect will be the center of your plaster mold. If you center the mold on a wheel head (or a banding wheel), you can measure down one of the lines in one inch increments (or go smaller or larger) and use a Sharpie to make concentric circles. You can use those to make slabs of specific diameters. Your other option, a bit more pricey, is to buy a set of MKM decorating disks which are plastic mats that have points for various divisions (fourths, fifths, sixths, etc.). I've seen some potters use the clear mats with squares marked on them that are used by quilters and sewers to mark and measure slabs. Link to comment Share on other sites More sharing options...
TheSmartCat Posted July 15, 2011 Report Share Posted July 15, 2011 Google <volumes and areas of shapes> Lots of sites with formulas available. Link to comment Share on other sites More sharing options...
Gwendeanne Posted July 19, 2011 Author Report Share Posted July 19, 2011 Thanks Bciskepottery, your instructions on making the paper circle under the mold worked and I found the center! Thanks also for the other suggstions, I will try both. Pottery requires so much of this type of measuring, any tips are helpful and always appreciated. Link to comment Share on other sites More sharing options...
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