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Here is my setup to make brushing glazes and underglazes by-the-jar

Glaze mixing setup

Let's make a low SG version of G2934BL, totally DIY. Weigh out a 340g batch of dipping glaze powder. Include 5g Veegum (to gel the slurry to enable more than normal water) and 5g CMC gum (to slow drying and impart brushing properties). Measure 440g of water initially (adjusting later if needed). Shake-mix all the powder in a plastic bag. Pour it into the water, which is blender mixing on low speed, and finish with 20 seconds on high speed. This just fills a 500ml jar. In subsequent batches, I adjust the Veegum for more or less gel, the CMC for slower or faster drying and the water amount for thicker or thinner painted layers. Later I also assess whether the CMC gum is being degraded by microbial attack - often evident if the slurry thins and loses its gel. Dipping glaze recipes can and do respond differently to the gums. Those having little clay content work well (e.g. reactive and crystalline glazes). If bentonite is present it is often best to leave it out. Recipes having high percentages of ball clay or kaolin might work best with less Veegum. Keeping good notes (with pictures) is essential to reach the objective here: Good brushing properties. We always use code-numbering (in our group account at Insight-live.com) and write those on the jars and test pieces. This is so worthwhile doing that I make quality custom labels for each jar!

Context: CMC Gum, Where do I start.., Glazing large bowls inside-and-out.., Brushing glazes on large.., Blending an engobe and.., Medium fire white bodies.., Two low fire transparent.., Make and sell your.., A 2oz jar of.., Amaco PC-2 vs Ravenscrag.., Here s how we.., Control gel using Veegum.., Learn to mix any.., Two methods to make.., Blender Mixing, Brushing Glaze

Tuesday 11th February 2025

What is the best 3D mechanical design software for ceramics in 2025?

CAD software and 3D printing are a potential revolution in vessel mold-making for ceramics (3D modelling is another topic). But there are two big problems: There is no way a potter, hobbyist or even small manufacturer can afford the typical software cost. While it is true most have free or low-cost trial or hobby versions, the strings attached are deal breakers. The second problem is the complexity of learning - that can be a bigger obstacle than cost.

Fusion 360 seems to offer a way to on-board the CAD world, using the free version and its great learning resources and best-in-class user interface. It is new and modern, a YouTube star. It is fully parametric supporting constraints and a timeline. True, it can choke on more complex drawings on consumer computers, but we don’t need to do those. But, for commercial use, it costs $680/yr. But that is cheap compared to some others! Upon discovery of the capability, the cost might be doable for you. If not, there is a second option: Move to Shapr 3D after learning. It costs $299/yr, also works on iPad (which Fusion 360 does not) and it is similar enough to make the transition easier. It is less powerful and lacks the training support, but the things it does do well are what is needed for mold making in ceramics. It uses the Parasolid engine like OnShape and SolidWorks (that royalty is probably what raises the cost).

Here are the ones you cannot afford (and maybe don't want):
-OnShape runs in your browser. It focuses on collaboration for teams. Free-version drawings are public but going private costs $1500/yr!
-Rhino is usable for CAD but targeted at modelling. It is not fully parametric and does not have a traditional timeline (however Rhino+Grasshopper is life-changing for geeks, both for CAD and modelling). $1000 to buy but upgrading is $500+.
-Solidworks is fully parametric with editable history. But it is old, the interface shows it. It is low cost for hobby use but for commercial use it is far out of reach for individuals ($2600/yr in 2025).
-FreeCAD is becoming more viable. It is parametric, has constraints and exports and imports popular formats (but with lots of issues). Its model tree is equivalent to the Fusion 360 timeline, but more clunky and depends on careful setting of constraints. The learning curve right now puts it out of practical reach of most. But a capital injection, like Blender got, is coming.

Context: G-Code 3D Printer instructions.., Fusion 360 on YouTube , Getting a consultant on.., All-in-one 3D printed block.., 3D Modeling, 3D Design, 3D-Printing

Monday 10th February 2025

Marbling stained porcelains - Watch out for firing shrinkage differences

A multicolored marbled porcelain bowl has cracked at the boundary between red and green

Stains can and do influence the degree of vitrification of a porcelain. Some stains will make a porcelain more refractory (decreasing fired shrinkage), others will make it more vitreous (increasing the firing shrinkage). Obviously, the greater the percentage of stain the greater the effect. Stained porcelains having differing fired shrinkages will stress at boundaries in accordance with the degree of difference in their fired shrinkages. In this piece, you can see how the boundary between the red (more vitreous) and green (less vitreous) porcelains is the point-of-failure. The only solution is to adjust the porcelain recipe to move the fired maturity in a direction that counterbalances the effect of the stain. For example, you could employ three recipes (regular, more vitreous, less vitreous) and use the indicated one for each stain added.

Context: Marbling, Firing Shrinkage

Monday 10th February 2025

Testing your own native clays is easier than you think

Simple tests being done on a found clay

Some simple equipment is all you need. You can do practical tests to characterize a local clay in your own studio or workshop (e.g. our SHAB test, DFAC test, SIEV test, LDW test). You need a gram scale (preferably accurate to 0.01g) and a set of callipers (check Amazon.com). Some metal sieves (search "Tyler Sieves" on Ebay). A stamp to mark samples with code and specimen numbers. A plaster table or slab. A propeller mixer. And, of course, a test kiln. And you need a place to put all the measurement data collected and learn from it (e.g. an account at insight-live.com).

Context: Shrinkage/Absorption Test, How to Find and.., Mother Nature's stoneware and.., These are behind the.., A must-have Laboratory variable.., Heavy duty mixer mounted.., Niko Leung finding and.., Get a kitchen blender.., Why you need to.., Case Study Testing a.., Characterization, Clay body, Native Clay, Brick Making, Digitalfire Insight-Live, Physical Testing, Slurry Up

Wednesday 29th January 2025

Standard 3/8 inch mold natch

Available on the Downloads page

Once you try these you will never go back to making molds without them. Unfortunately, these are not easy to get in North America. Or even online. But you can 3D print them yourself (we use PLA filament). This design interlocks with standard 3/8" natches used in industry. There are more aspects to printing and using these than meets the eye, here are some aspects to know:

-The base can be widened for sticking on the build plate better. If you need to print large numbers it might be advisable to use a glued plate to make sure they stick well.
-The inner edge is chamfered to ensure better insertion of the nipple.
-Print without infill for better strength.
-These are hollow, no support is needed.
-The bottom can be widened to stick better to the build plate.
-The ribs can be moved.
-A 9.8 mm hole is needed in the mold.

Context: Coming soon Throw the.., 3D printed three-piece jigger.., CAD drawing for 3D-printing.., Mold Natches, F3D

Wednesday 29th January 2025

The best way to make black clay: Don't.

Make a black clay body with stain

To prove that using an engobe is the best way to make a black cone 6 stoneware clay surface consider the mug on the left, a version of L4768E. This is not the best way but it is the one most used (and what Plainsman Clays does with Coffee Clay). This is a DIY mix, the darkest that it is practical (I used the hyper-red burning C-Red clay as a base, thus needing much less umber to darken it). While it looks black beside red burning bodies, beside this true black it doesn't, First, it is not a body, it is just a thin veneer of stained porcelain engoben (if the surface is all we see why stain it all the way through?). That being said, some people need a totally black and safe clay, like this one, and can afford to make it themselves (if that is you try using the L4053B recipe as a starter). Get a plaster table and a propeller mixer and you will be unstoppable!

What about using metal oxides to make the engobe? Black stain is expensive but is far superior (and safer) for black. Consider using 10-15% colorant in this 500g mug, which would require 50-75 grams of stain (~$5-8). 10% stain in an engobe applied in this thin layer likely needs only a few grams of stain (for pennies of cost). What about using a commercial black underglaze? There are normally vitreous, would stick to a kiln shelf and not cover evenly like this.

Context: A special gummed engobe.., L3954J black engobe on.., Stained engobes can be.., Brushing engobe fitted to..

Monday 27th January 2025

What does Goldart look like if you fire it by itself?

Goldart fired bars

Goldart (left) compared to Plainsman Midstone (right). Goldart is a buff and vitreous stoneware at cone 10R. These are fired at cone 7, 8, 10 oxidation and 10 reduction (bottom to top). Soluble salts in the Goldart impart a darker coloration to the reduction fired bar). The Midstone has some coarser particles that make for larger speckles in reduction.

Context: Goldart, Midstone

Saturday 25th January 2025

Are you a doctor? Prescribe pottery!

Two doctors prescribing pottery

These two AI dotors are really with the plan! Everyone knows the calming effect pottery can have, no wonder it is recommended over chemicals as a way to deal with stress. Pottery acts as a form of meditation, creative therapy, and stress relief all rolled into one. The MidJourney.com AI doctor on the right is perfecting his skills at home before recommending them to patients. His six-fingered hands doubtless improve quality of the ware. The Google Gemini doctor on the left is very serious about the potential of pottery, having integrated her potter's wheel right into her office desk. She is a very clean thrower also. Pottery offers a unique combination of benefits that can be therapeutic for those dealing with stress and depression:

-The process of working with clay demands focus and presence. The tactile nature of the material and the repetitive motions can help quiet the mind and induce a "flow state" where you lose track of time and worries.
-Pottery enables you to channel feelings into something tangible and beautiful, fostering a sense of accomplishment and control.
-Creative activities can lower stress hormones and the physical act of kneading and shaping clay can release tension.
-Successfully creating a piece of pottery, no matter how simple, can boost confidence and provide a sense of pride.
-Joining a pottery class or group can provide a sense of community and belonging, reducing feelings of isolation.

Context: Where do I start..

Thursday 23rd January 2025

New Facebook group: CAD+3D = Molds for Ceramics

It is about using consumer 3D printers (and mostly PLA filament) and professional CAD software (now available for DIYers) to make plaster molds for ceramics. It prioritizes being green, learning to formulate and use your own casting bodies and glazes. Here is what you'll gain:

-Step-by-step guides.
-A constant emphasis on using as little filament and producing as little waste as possible.
-Insights into the cost-effectiveness and simplicity of these tools.
-Motivation to build your own repository of designs, constantly build better skills to improve them and leverage rapid redesign cycles and efficient production.
-Learn to formulate, mix, test and adjust your own casting bodies.

Whether you're a curious hobbyist or a seasoned mold maker, this group will show you why these technologies are the future. It's easier, more affordable, and more rewarding than you think. Let’s mold the possibilities together!

Context: Join our Facebook group..

Thursday 23rd January 2025

Stained engobes can be applied thinly yet fire opaque

A black engobed leather hard mug

This black engobe, L3954F, is on a cone 6 buff stoneware (at leather hard stage). It contains only 7.5% Mason 6600 black stain. How is that possible? Why do people add so much more to their underglazes? Because this recipe has been tuned to have the same degree of maturity as the body - it therefore fires totally opaque. This contrasts with underglaze/engobe recipes containing significant frit, among other issues, their vitreous nature renders them translucent. Thus, up to 40% stain is needed to crowbar their opacity enough to intensify color. And a thicker application (that carries other issues).

Notice how thinly and evenly this is applied. This was possible because of another key factor: The slurry was adjusted to be thixotropic. The thinner layer enables drying more quickly. The body-compatible engobe recipe also means fewer issues with flaking during drying, better fire-fit.

Context: Absolutely jet-black cone 6.., The best way to.., Engobe

Thursday 23rd January 2025

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