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2019 Jiggering-Casting Project of Medalta 66 Mug
A cereal bowl jigger mold made using 3D printing
Beer Bottle Master Mold via 3D Printing

Build a kiln monitoring device
Coffee Mug Slip Casting Mold via 3D Printing
Comparing the Melt Fluidity of 16 Frits
Cookie Cutting clay with 3D printed cutters
Evaluating a clay's suitability for use in pottery
Make a mold for 4-gallon stackable calciners
Make Your Own Pyrometric Cones
Making a high quality ceramic tile
Making a Plaster Table
Making Bricks
Making our own kilns posts using a hand extruder
Making your own sieve shaker for slurries
Medalta Ball Pitcher Slip Casting Mold via 3D Printing
Medalta Jug Master Mold Development
Mold Natches
Mother Nature's Porcelain - Plainsman 3B
Nursery plant pot mold via 3D printing
Pie-Crust Mug-Making Method
Plainsman 3D, Mother Nature's Porcelain/Stoneware
Project to Document a Shimpo Jiggering Attachment
Roll, Cut, Pull, Attach Handle-making Method
Slurry Mixing and Dewatering Your Own Clay Body
Testing a New Load of EP Kaolin
Using milk as a glaze

Better Porosity Clay for Brown Sugar Savers

Terra Cotta brown sugar savers are made by hundreds of companies and individuals. However would you like to make ones that have triple the porosity and are safer? Standard terra cotta clays need to be fired to cone 06 at least (to assure they will not chip or break at the edges). Ideally, they should be fired to cone 04. That means typical porosity will be about 8-12% (as measured by the SHAB test). However terra cotta clays have an issue regarding safety: Their geological origins, by definition, make them contaminated clays. Contaminated with iron, calcium, magnesium, sodium, and potassium in significant amounts (e.g. 1% or more). These contaminants act as fluxes, causing the clay to vitrify at low temperatures. Terra Cotta clays are nature's trace element library of the periodic table of elements, these are present in compounds that are both soluble and insoluble. The darker the colour and the less porous they are the more likely they are terra cotta.

For many years I have suggested to people that they use a clay specifically formulated to have a much higher porosity and have the potential to be safer. The vast majority of people just answered that it was not a big deal. But I think it is - the whole purpose of these discs is to be porous and making them more porous has to be better.

I am still testing, stay tuned for the recipe and what you need to know to use it. In the meantime we can help you develop a body in a group account at In doing this you will learn the secret material that makes the high porosity possible.

Related Information

Terra Cotta brown sugar savers on Amazon - you can do better

Brown sugar saver clay

These are sold at a wide range of prices. We bought two of these and tested their porosities. One absorbed 10% of its weight in water. That means a 30-gram saver would soak up only 3 grams of water. The other soaked up three times as much. The manufacturer of that one took advantage of the extra porosity by making a saver half the weight of the others. That one is not a terra cotta, they are iron staining a mix of commercial kaolin or ball clay and adding a filler.

By Tony Hansen
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