We have included this page to warn you about recipes that you find online. Be careful about wasting your time. And money. Do not think you will find a magic solution to all your dreams! What you will more likely find is alot of frustration and a stock of useless materials. Better to have a few recipes you understand and can control than 50 renegades that put you through hell to use and keep consistent or just work sometimes.
Reason 2 for record keeping in an insight-live.com account
It is so much easier to print a mix ticket for whatever total you want. Resulting in fewer errors, more confidence in batches you have mixed.
Reason 1 for record keeping in an insight-live.com account
Notes. It is a much better place to take notes than that old binder you use. And the chance of losing them is the same as the chance of losing the phone that you access them with. No, wait, it is way less. Because any internet connected phone or device with a browser can be used.
Is this your record keeping system?
Keeping your valuable notes like this? Recipes? Test results? Are your pictures lost in a cellphone with no keywords or connections to anything? If you test and develop you need to organize in a way that a book cannot do. Like link recipes to each other and other things like pictures and firing schedules. You need to group test recipes in projects, classify them. Calculate chemistry and mix tickets. Research materials. Do keyword searches. Book and binder records do not do this. Your account at Insight-live.com does!
Trafficked online recipes waiting for a victim to try them!
Last week a customer came to buy materials to mix these recipes she found online. Then we had a closer look. Many have 50+% feldspar/Cornwall/nepheline with little dolomite or talc to counteract their high thermal expansion, these are guaranteed to craze. Many are high in Gerstley Borate, it will turn the slurry into a bucket of jelly. Some have high tin, lithium and cobalt; exceptionally expensive materials. Many have metal carbonates, which can produce blisters and bubbles in the fired surface. Some contain almost no clay, they will settle like a rock in the bucket. A better way? Identify the mechanisms (colorants, opacifiers and variegators) in each and transplant these into your own base transparent glossy and matte recipes. These already fit your bodies, have good slurry properties and are stable. Use stains instead of metal oxides when possible.
Reason 3 for record keeping in an insight-live.com account
Its cleaner! When you finish mixing a batch you can throw away the mix ticket. You will be printing another the next time. And likely to a different total.
The next time I buy a bunch of materials to test an undocumented online recipe slap me!
Look at recipes before wasting time and money on them. Are they serious? This is a cone 6 GLFL test to compare melt-flow between a matte recipe, found online at a respected website, and a well-fluxed glossy glaze we use often. Yes, it is matte. But why? Because it is not melted! Matte glazes used on functional surfaces need to melt well, they should flow like a glossy glaze. How does that happen? This recipe has 40% nepheline syenite. Plus lots of dolomite and calcium carbonate. These are powerful fluxes, but at cone 10, not cone 6! To melt a cone 6 glaze boron, zinc or lithia are needed. Boron is by far the most common and best general purpose melter for potters (it comes in frits and gerstley borate, colemanite or ulexite; industry uses more boron, zinc and lithia frits). The lesson: Look at recipes before trying them.
Yikes. Cutlery marking this bad on a popular glaze!
An example of how a spoon can cutlery mark a glaze. This is a popular middle temperature recipe used by potters. The mechanism of its matteness is a high percentage of zinc oxide that creates a well-melted glaze that fosters the growth of a mesh of surface micro-crystals. However these crystals create tiny angular protrusions that abrade metal, leaving a mark. Notice the other matte flow on the left (G2934), it not only has a better surface (more silky feel) but also melts much less (its mechanism is high MgO in a boron fluxed base). It is does not cutlery mark at all!
A good matte glaze. A bad matte glaze.
A melt fluidity comparison between two cone 6 matte glazes. G2934 is an MgO saturated boron fluxed glaze that melts to the right degree, forms a good glass, has a low thermal expansion, resists leaching and does not cutlery mark. G2000 is a much-trafficked cone 6 recipe, it is fluxed by zinc to produce a surface mesh of micro-crystals that not only mattes but also opacifies the glaze. But it forms a poor glass, runs too much, cutlery marks badly, stains easily, crazes and is likely not food safe! The G2934 recipe is google-searchable and a good demonstration of how the high-MgO matte mechanism (from talc) creates a silky surface at cone 6 oxidation the same as it does at cone 10 reduction (from dolomite). However it does need a tin or zircon addition to be white.
A flameware recipe. Are they kidding?
This is a flameware, made from a recipe promoted by a popular website. Are they serious? How could you throw this? Maybe it is possible, but we need an explanation. How could the page fail to mention how coarse this surface would be? How porous and weak ware would be? We find many body and glaze recipes on the internet. These almost always just sit there, taking screen space, not explaining themselves in any way.
How do you turn a transparent glaze into a white?
Right: Ravenscrag GR6-A transparent base glaze. Left: It has been opacified (turned opaque) by adding 10% Zircopax. This opacification mechanism can be transplanted into almost any transparent glaze. It can also be employed in colored transparents, it will convert their coloration to a pastel shade, lightening it. Zircon works well in oxidation and reduction. Tin oxide is another opacifier, it is much more expensive and only works in oxidation firing.
The rutile mechanism in glazes
2, 3, 4, 5% rutile added to an 80:20 mix of Alberta Slip:Frit 3134 at cone 6. This variegating mechanism of rutile is well-known among potters. Rutile can be added to many glazes to variegate existing color and opacification. If more rutile is added the surface turns an ugly yellow in a mass of titanium crystals.
Cone 6 glaze speckling mechanism
This cone 6 white opacified glaze has an addition pigment-bearing granular mineral to create speckle (e.g. illmenite, manganese granular, ironstone concretions). This speckling mechanism can be transplanted into almost any glaze. Unfortunately, the metallic particles that produce the speck are often heavy and settle quickly in the glaze slurry. This can be prevented somewhat by flocculating the slurry.
Why does this glaze look like this? What are its mechanisms?
This is cone 6 an oxidation transparent glaze having enough flux (from a boron frit or Gerstley Borate) to make it melt very well, that is why it is running. Iron oxide has been added (around 5%) producing this transparent amber effect. Darker coloration occurs where the glaze has run thicker. These are all simple mechanisms, which, once understood, can be transplanted into other glazes. This glaze is also crazing. This commonly occurs when the flux used is high in K2O and Na2O (the highest expansion fluxing oxides). K2O and Na2O produce the brilliant gloss. They come from feldspars, nepheline syenite and are high in certain frits.
Compare two glazes having different mechanisms for their matteness
These are two cone 6 matte glazes (shown side by side in an account at Insight-live). G1214Z is high calcium and a high silica:alumina ratio (you can find more about it by googling 1214Z). It crystallizes during cooling to make the matte effect and the degree of matteness is adjustable by trimming the silica content (but notice how much it runs). The G2928C has high MgO and it produces the classic silky matte by micro-wrinkling the surface, its matteness is adjustable by trimming the calcined kaolin. CaO is a standard oxide that is in almost all glazes, 0.4 is not high for it. But you would never normally see more than 0.3 of MgO in a cone 6 glaze (if you do it will likely be unstable). The G2928C also has 5% tin, if that was not there it would be darker than the other one because Ravenscrag Slip has a little iron. This was made by recalculating the Moore's Matte recipe to use as much Ravenscrag Slip as possible yet keep the overall chemistry the same. This glaze actually has texture like a dolomite matte at cone 10R, it is great. And it has wonderful application properties. And it does not craze, on Plainsman M370 (it even survived a 300F-to-ice water IWCT test). This looks like it could be a great liner glaze.
Tune your matte glaze to the degree of matteness you want
G2934 is a popular matte for cone 6 (far left). It is not matte because it is not melting enough or is covered with micro-crystals, it is an MgO matte (a mechanism produces a more pleasant surface that cutlery marks and stains less). But what if it is too matte for you? This recipe requires accurate firings, did your kiln really go to cone 6? Proven by a firing cone? If it did, then we need plan B: Add some glossy to shine it up a bit. I fired these ten-gram GBMF test balls of glaze to cone 6 on porcelain tiles, they melted down into nice buttons that display the surface well. Top row proceeding right: 10%, 20%, 30%, 40% G2926B added (100% far right). Bottom: G2916F in the same proportions. The effects are similar but the top one produces a more pebbly surface.
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