Monthly Tech-Tip from Tony HansenI will send practical posts like these (from thousands I maintain). No ads or tracking. We are troubleshooting the confirm email, for now you will be subscribed immediately (the first monthly email will provide one-click unsubscribe). BlogTest bars from a few days of firingsHere is how to enter the data into Insight-live![]() Multiple batches of fired test bars, organized by temperature, have already been weighed and measured (the weights and lengths are written on the sides of the bars). Each batch is accompanied by the cones from the firing in the test kiln (these influence how the temperature is recorded and adjustments to kiln firing schedules). Since we are working on many runs, tests and projects at any given time, these tests pile up rapidly. And they generate a lot of SHAB test data that needs to be input into your Insight-live.com account promptly. Context: Shrinkage/Absorption Test, Entering TestData Into Insight-Live.., Physical Testing Thursday 27th March 2025 DIY mold making using 3D printing just got easier.Mold natches, spacers, clips and embedsAvailable on the Downloads page ![]() Plastic natches are cast into plaster molds to provide a durable and good-fitting interlock between pieces. The traditional self-interlocking 3/8" or 9.5 mm (nipple diameter) one has not proven suitable for mold making based on 3D printing. Our solution is a four-part system. To use it, your 3D printed mold shells only need matched 13.5mm holes. Context: DIY natches spacers and.., CAD drawing of handle.., Standard 3 8 inch.., Glue-sticking the 3D printer.., Downloadable 3D model for.., Casting Slip, Mold Natches, Mold Natches Wednesday 26th March 2025 Mixing and pouring plaster into a 3D printed shell mold-Size of mixing container: 1L per 1000g of plaster. Context: Glazy Plaster Calculator, USG Plaster mixing instructions.. Tuesday 25th March 2025 Mason stains in the G2934 matte base glaze at cone 6![]() Stains can work surprisingly well in matte base glazes like the DIY G2934 recipe. The glass is less transparent and so varying thicknesses do not produce as much variation in tint as glossy bases do. Notice how low many of the stain percentages are here, yet most of the colors are bright. We tested 6600, 6350, 6300, 6021 and 6404 overnight in lemon juice, they all passed leach-free. The 6385 is an error, it should be purple (that being said, do not use it, it is ugly in this base). And chrome-tin pink and maroon stains do not develop the color (e.g. 6006). But our G1214Z1 CaO-matte comes to the rescue, it both works better with some stains and has a more crystal matte surface. The degree-of-matteness of both can be tuned by cooling speed and blending in some G2926B glossy base. You can mix any of these into brushing or dipping glazes. Context: Mason 6021 Red Stain, G2934, Stains Mason, G1214Z1, 5 titanium dioxide in.., G2934 cone 6 DIY.., Here is my setup.., Medium Temperature, Base Glaze, Ceramic Stain, Cone 6 Thursday 20th March 2025 Mason stains in the G2926B base glaze at cone 6![]() This glaze, G2926B, is our main glossy base recipe. Stains are a much better choice for coloring it than raw metal oxides. Other than the great colors they produce here, there are a number of things worth noticing. Stains are potent; the percentages needed are normally much less than for metal oxides. Staining a transparent glaze produces a transparent color, it is more intense where the laydown is thicker - this is often desirable in highlighting contours and designs. For pastel shades, add an opacifier (e.g. 5-10% Zircopax, more stain might be needed to maintain the color intensity). The chrome-tin maroon 6006 does not develop well in this base (alternatives are G2916F or G1214M). The 6020 manganese alumina pink is also not developing here (it is a body stain). Caution is required with inclusion stains (like #6021). Bubbling, as is happening here, is common - this can be mitigated by adding 1-2% Zircopax. And it’s easy to turn any of these into brushing or dipping glazes. Context: Mason 6021 Red Stain, Stains Mason, G2926B, Concentrate on One Good.., Mason 6600 Black Stain, Here is my setup.., G2926B cone 6 transparent.., When using stains customize.., Medium Temperature, Cone 6, Colorant, Base Glaze, Ceramic Stain Thursday 20th March 2025 Gunmetal black mug demos liner glazing:Safe glaze inside, pigmented matte outside.![]() The outside glaze is G2934Y cone 6 black. I use the C6DHSC slow cool firing schedule to get this degree of matteness in the black. The body is the natural MNP (Mother Nature's Porcelain), it vitrifies to zero porosity around cone 4 (yet is stable to cone 8). At cone 6 it produces incredibly strong ware and works well with these two glazes. The inside liner glaze is GA6-B (made using real Albany Slip rather than Alberta Slip in this case). Although the melt characteristics of these two glazes are so different they can be applied to meet in a perfect line at the rims of pieces. Food safety labelling is not what you think it is - do liner glazing to be safe. Context: Albany Slip, Meet two glazes at.., Feeling good about the.., Liner Glazing Thursday 20th March 2025 Shrinking glaze = peeling glaze![]() Dipping glazes peel like this because they contain clay and shrink as they dry (the fact that all of them don't do this is actually amazing). Success is a matter of the shrinkage being low enough, the drying being fast enough, the layer being thin enough, the bisque being absorbent enough, and the bond with the bisque being good enough. Glazes with high clay content, thick applications or multi-layering are the main offenders. Thixotropic slurries apply most evenly and are least likely to go on too thick. Dipping glazes having 15-20% kaolin or ball clay are easiest to slurry up and have the best application and drying properties. Mixing base layers as first-coat dipping glazes is also important. Context: Glaze Layering, Glaze peeling on drying.. Friday 14th March 2025 A potter fixes a leaching glaze problem![]() G1214Z1 is a popular cone 6 calcium matte glaze recipe. It has very high melt fluidity, enabling a fine grained crystalline matte surface to develop during cooling. A potter was steered to this recipe after finding that G2934 magnesia matte fired too variegated when stained blue. However, her first effort with this failed a leaching test. She had a secret weapon: An account at Insight-live.com, where recipes and their calculated oxide formulas can be compared side-by-side. Leaching glazes are most often runny because they contain excessive fluxing oxides. She simply increased the SiO2, it is the glass that makes up the lion's share of all glazes (higher amounts of it characterize glossy glazes). Al2O3 couples with it to improve durability (and the Si:Al ratio is a factor in the degree of matteness). With an accompanying small increase in the B2O3, the magic glass:flux that makes most cone 6 glazes possible, the got the result on the right. The good news: It passed the GLLE test for leaching. There is a lesson here: She had to compromise the degree of matteness a little to get the food safe product. A benefit is that it is also less prone to cutlery marking. Happily, it turned out that much less blue stain was needed. Context: G1214Z1, G1214Z matte glaze melt.. Friday 7th March 2025 Testing a new brand of dolomite![]() Dolomite is a key material for glazes, especially mattes. We were forced to adopt a new brand and needed confidence it was equivalent. Three tests were done to compare the old long-time-use material (IMASCO Sirdar) with a new one (LHoist Dolowhite). The first melt flow tester compares them in a very high dolomite cone 6 recipe formulated for this purpose; the new material runs just slightly more. The second tester is uses the G2934 cone 6 MgO matte recipe with 5% black stain; the new material runs a little less here. The third test is the high dolomite glaze on a dark burning clay to see the translucency and compare the surface character. They are very close. These three gave us the confidence to proceed. Context: Dolomite, Glaze Melt Flow -.., Downloadable 3D model for.., Material Substitution, Melt Fluidity Wednesday 5th March 2025 Melt fluidity differences are not obvious by just comparing glazed ware![]() These two Plainsman M370 test mugs were fired at cone 6, the left one with G2934 matte glaze, the right one with G2934Y4 matte. They look and feel identical in the hand. The two glazes have the same chemistry. But they employ different materials to source that chemistry. The secret of of the matteness is high MgO (magnesia content). In the glaze on the left MgO is sourced by dolomite, a lot of it. The glaze on the right sources it from a special frit, Ferro 3249. The impact of this difference is visible in the melt fluidity tester, the fritted one is melting and flowing much better. On other clays, especially stonewares, the G2934 can have a dry surface that cutlery marks. Thicker applications make it worse. But the Y version exhibits no such issues. Its mattness, durability, cleanability and hardness are so good that it is being used in floor tile. Context: G2934Y, Downloadable 3D model for.., G2934Y variations for fired.., Melt Fluidity Tuesday 4th March 2025 | Contact MeUse the contact form at the bottom on almost all the pages on this site or let's have a Other ways to Support My WorkSubscribe to Insight-Live.com. 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Login to your online account Chemistry plus physics. Maintain your recipes, test results, firing schedules, pictures, materials, projects, etc. Access your data from any connected device. Import desktop Insight data (and of other products). Group accounts for industry and education. Private accounts for potters. Get started. Download for Mac, PC, Linux Interactive glaze chemistry for the desktop. Free (no longer in development but still maintained, M1 Mac version now available). Download here or in the Files panel within your Insight-live.com account. What people have said about Digitalfire
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