This glaze is "stretched" on the clay so it cracks. When the lines are close together like this it is more serious. If the effect is intended, it is called "crackle" (but no one should intend this on functional ware). Potters, hobbyists and artists invariably bump into this issue whether using commercial glazes or making their own.

"Art language" solutions don't work, at least some technical words are needed to understand it. Crazing is a mismatch in the thermal expansions of glaze and body. Most ceramics expand slightly on heating and contract on cooling. The amount of change is very small, but ceramics are brittle and glazes are rigidly attached. If they are stretched on the ware cracks will occur to relieve the stress (usually during cooling in the firing but sometimes much later). All glaze manufacturers advise against crazing on functional ware.

We wanted to compare the melt fluidity of G2934Y (left) to G2934 (right). To do that we prepared GBMF test balls (see below). The forming and drying process leave a flat spot so the gumball-sized balls are easy to place on a porcelain tile. During firing they flatten out. The degree to which they do acts as a measure of the flow (when compared with another). Many characteristics that one would not observe on glaze tiles reveal themselves in this test. In this case, we needed to know if the melt flow was at least as good (and this proves it is better). Reactive glaze tend to be the norm in recent years, their primary characteristic is being runny (having high melt fluidity). Their fired character...

Reactive glazes don't melt into a homogeneous melt and they don't freeze as a typical glass. The physical nature of the material powders (e.g. their particle size and the individual nature of how they respond to heat, soften, melt and interact with their own kind and others) create a melt that does not solidify into a homogeneous glass. These glazes are said to be dynamic. And unpredictable effects often occur during firing, like color variegation, speckles, streaks, mottled and flowing textures, crystallization, pooling, etc. The outcome is influenced by factors such as the materials chosen to source the needed oxides, firing schedule, kiln atmosphere, cooling or heating cycle, etc. These glazes are at their best when each piece has a unique, artistic character. But, this is also their worst feature, making them "tipping point glazes", ones whose visual character is a product of fragile and not well understood features of the materials and process. Small changes typically produce big changes in fired appearance (often to the chagrin of the potter).

I wanted an easy way to make molds for slipcasting handles that mate perfectly to any shape mug (or pitcher, teapot, etc). I want to pair cast with thrown or jiggered elements and join them using just slip (even when the clay is stiff). We have developed a flexible CAD design that puts 3D printing of case molds within the reach of almost anyone. It requires so little tooling it can be done in a kitchen using spoon mixing and a paper cup! These PLA shells, for example, print quickly to only 11 grams and they peel away from the plaster with a heat gun to give fine detail and perfect fit. Multiple cycles of redesign and print are practical to achieve just the right shape and fit. Cast handles can be produced in quantity and stored in a damp box, removing one of the biggest hassles in the production of handled ware. The feel of the handle is the first thing customers notice, even a hobbyist can now turn a "wet noodle" handle into something designed and utilitarian.

For many years we have searched for a credible alternative to our Lightnin lab mixer. We found this unit on Amazon but then bought it from FristadenLab in Nevada. These are made in China but packaged, documented, shipped and supported in Nevada. This cost about $300US (a programmable one costs a little more but this is the better option for ceramic slurries). The first impression is how heavy the unit is. The base is 1/4" solid steel. The rods are all solid stainless 5/8". The clamp is also solid metal. The shaft is 3/8" and is held in place by a good quality chuck which enables easy release. The propeller is about 2 1/2" in diameter and screws on, it would thus be easy to 3D print other propellers and mount them on a hex nut (e.g. to fit into glaze jars). The locking mechanism enables mounting at an angle (important when trying to achieve the highest speed without sucking air bubbles). It plugs in via a 24v DC adapter (which means it has a DC motor). When switched on it speeds up gradually and the dial offers fine control of speed. On this occasion, we mixed 3500g of plaster in this 2 IMP gallon bucket (2.5 US gallon) with no problem. It runs completely silent and should easily mix this pail full of glaze or casting slip. A propeller mix like this is a great start to DIY glazes.

The way potters and hobbyists traditionally pack electric kilns is the height of energy wastage. This 18x22 hexagonal kiln load of bowls is a good example. A traditional pack on the left does 24. The new method using 3D printed setters on the right does 36. The left firing contains only 5.3 kg of bowls with more than 60kg of furniture - each 220g bowl incurs 2700g (6 lb) of kiln furniture weight - seven times as much! This type of packing also leads to uneven firing and puts a heavy load on the electrical components. The bigger the kiln the greater the efficiency.

These light-weight stackable setters don't exist yet. But they soon will. I designed specifically for this bowl and printed samples using PLA. Sintered alumina, the ultimate material, has 3x density over PLA - so we can predict the weight at 160g. These setters allow free flow of air, even the foot of the bowl is exposed. They can be printed upside down with one pass of the nozzle for most of the geometry.

New uV hardened resins for dental applications are the inspiration for this idea. These resins and hardeners are commodity items online now, anyone with a clay 3D printer (or the ability to retrofit an existing PLA printer) can experiment with recipes (even of inexpensive refractory materials like kaolin, ball clay silica) and print these.

Simply put: Glaze misfit. The glaze is under compression and it is pushing outward. That compression was created as these terra cotta pieces cooled in the kiln. After the glaze solidified, somewhere above red heat, it became a glass and began to contract. The body, to which that glaze is attached by a glass bond, had its own higher rate of contraction. The glaze has some advantages in this battle. Its thick application gives it extra power to assert its thermal expansion. The body is over-fired and has become brittle. The unglazed outsides, incised designs and varying thickness provide points of weakness where cracks can start. The body resists the relentless force from inside but the odds were stacked against it and the pieces do not even make it out of the kiln. Of course, the glaze could be applied thinner, ware could be fired lower, it could have a more even cross-section and the outsides could be glazed. All will help, but increasing the thermal expansion of the glaze (by increasing KNaO at the expense of other fluxes), is one change that would fix this issue.

Lilly will take you step-by-step through the 3D design process of drawing a propeller. We tried many methods of doing this to finally arrive at a simple procedure that produces a flexible parametric design. Follow the full transcript as you watch. You can use the same process to create one in this or other CAD software. Our design has only nine steps yet is flexible enough to accomodate a different number of blades, changes in the blade shape, angle, thickness and size and different heights and diameters for the hub and hole. If you would like this 3D file in Fusion 360 format, it is available in the Files manager in your Insight-live.com account.

In the past, we have used Adobe Premiere for making videos. This video marks our transition to using KDenlive instead (please be patient with the rough edges until we learn this better). We are using it on Linux! It is amazing that a tool this powerful exists as free software (although they accept donations).

This assembly is the bottom half of a 3D printed 0.8mm wall thickness PLA mold. Until now I have super glued a thin disk onto the bottom, but a plaster pour again woke me up to how much outward pressure the heavy slurry exerts on molds tasked to contain it - the glue failed! This time I am doing a "belt and suspenders" solution. This bottom disk is much thicker and stronger and it is removable. These paper clamps hold it onto the flange and are recessed so the whole thing can sit flat-side down on the table.

Cutting-edge ceramic 3D printing is happening in dental! The focus is not primarily on the printers, attention is going into the paste. They are calling it "the resin" because acrylic resin is the likely medium. Pure alumina powder is being used (also pure silica). Imagine having a pure alumina tooth! What temperature does it take to fire these (and burn out the photopolymer network)? 1600C! They are achieving high percentages (likely 70%+) of the powder in an acrylic resin base and yet the slurry is very fluid (so it can be printed in a very narrow extrusion) and has minimal fired shrinkage. They are adding uV hardeners, this enables solidifying the material as soon as it leaves the printer nozzle. Data sheets specify exactly what uV wave length is needed. The key to the success of these efforts is meticulous lab work to perfect and adapt already established processes and materials. This material-centric lead could be adapted to so many other branches of ceramic fabrication and so many other materials could be made into resins. Another exciting area is investment casting. Thin ceramic shells are being printed and molten metal poured in to get shapes never before possible.