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glazenerd

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  1. Like
    glazenerd reacted to Brandon Franks in My First Crystalline Attempts   
    Crystalline Update:
     
    Achieved round crystals
    Ability to control population 
    Experimenting with colors
    Nearly finalized base recipe
    Nearly finalized firing schedule
    Improved throwing abilities 
     
     
    (My attached picture is from my most recent load, I resupplied my zinc and got a very reactive batch, I am adjusting the percentage .75 grams/batch which I have judged appropriate based on the other firing results)
     

  2. Like
    glazenerd got a reaction from Marcia Selsor in A trend observed   
    I started in 2007, after I saw a crystalline piece- most know the story. I knew when I started, it would be part time until I retired.
  3. Like
    glazenerd got a reaction from Roberta12 in A trend observed   
    I started in 2007, after I saw a crystalline piece- most know the story. I knew when I started, it would be part time until I retired.
  4. Like
    glazenerd reacted to liambesaw in From 4 cuft to 12 cuft, finally got a big boy kiln!   
    There it be!  Gonna need a dang step stool to load it though haha

  5. Like
    glazenerd reacted to Pres in Beginning wheel throwing projects   
    Just saw that I had missed this post, so glazednerd, just yesterday I was working with a few students (adults) and one was having the same problem you were. I told them that instead of ending the pull at the top of the pot to imagine that the pot was an inch or so taller and to "follow through" with the pull. This does help when coming to the top of the pot.
     
    best,
    Pres
  6. Like
    glazenerd reacted to neilestrick in Clay toxicity test for using in cookware   
    From a technical/legal standpoint, the non-toxic label does not mean it is food safe. A glaze can be certified non-toxic but not be food safe, and vice versa. In the US, all restaurant dishes are required to be made of vitrified clay with a smooth surface that can't harbor bacteria.
    I totally agree with @liambesaw. Most of what is being promoted on that website is marketing mumbo jumbo. Any commercially available clay bodies will likely have the same test results. She claims her clay is so pure that it's edible, and so is any commercial clay body with a non-toxic label. Nutrients? She also implies that pots that the rest of us use a lot of chemicals in making our pots, which is ridiculous. Even clays from 'isolated' areas can have naturally occurring lead in them. Where does she think lead comes from? It's an element, after all. I have a hard time believing that there is zero ppm lead in her clay. I'd like to see the actual report with the name of the lab, etc. The biggest danger with her unglazed pottery is the risk of food-borne illness from not using it properly since it's porous.
  7. Like
    glazenerd reacted to Hulk in Testing for clay origins   
    Hearst brought a few tons of building materials to California from across the pond.
    The black clay here in Los Osos is quite sticky and plastic. There are places where the cracks are over thirty feet deep by early Fall, when the shrinkage peaks (a few miles from here - our house is on sand) ...wonder if the San Luis Obispo mission adobe is from here? Being curious,
    "Roofing tiles, called tejas, were made from the same materials as the adobe bricks. A flat rectangle of clay was formed. It was then carefully placed over the round piece of a log which had been sanded so the clay wouldn’t stick to the wood. Some stories tell that the roof tiles were molded over the legs of the Indian workers, but other sources say that is just a legend.
    After the clay was molded into the curved shape, it was dried in the sun for several days. Then the tile was baked in a kiln for many days. The baking at a high temperature caused the adobe clay to turn red.
    Mission San Luis Obispo has been credited with the development of roofing tiles. Father Serra’s diaries, however, say that the first roofing tiles were made at Mission San Antonio de Padua. Mission San Luis Obispo then perfected the process. They made the tiles in large quantities and supplied them to other nearby missions. At San Luis Obispo, horses were kept walking in circles to mix the adobe clay with their hooves.
    Some mission buildings had tiles on the floor. These floor tiles, called ladrillos, were made from a thicker mixture of adobe clay, straw, and water. They were molded in much the same manner as the adobe bricks, partially dried in the sun, and then baked in kilns to make them hard.
    Adobe tiles were also used as water pipes at many missions, to carry the water from a river or stream to the mission compound, or to the fields for irrigation.
    Pottery bowls and pots were made at the missions, though not in great quantities. Clay pots were not commonly made by the California Indians, who instead made excellent baskets which served their needs for storing food. However, in later years some missions had pottery wheels for making bowls."
    "Because of flaming arrows, the mission was built with tiles; the first roof tiles made in California."
    "To Mission San Luís Obispo goes credit for establishing the use of red tile roofs that became a symbol of the California missions. Though first used at Mission San Antonio de Padua, roofing tiles were perfected and produced on a large scale by Mission San Luís Obispo.  The roofing tiles were patterned on those remembered by the padres from their days in Spain.  Water and local clay was mixed by having horses walk around in circles through the clay, which was then formed over curved wooden molds of tree trunks, dried in the sun and baked in a kiln.  The tiles were about 22 inches in length and tapered from 12 to 20 inches in width. Water came from a nearby stream, and was used to power a gristmill. 
    ...
    1769   Governor Portolá, on his way from San Diego north to Monterey, crossed a valley where grizzly bears were eating the tule roots in the marshy ground; named it La Cañada de los Osos (Valley of the Bears) and returned to the valley to get meat for the soldiers and missions.
    1772   Father Serra founded the mission; left the next day to return to San Diego, leaving Father José Cavaller in charge of building a chapel, barracks, priests' house and workshops of logs and tules.
    1773   Group of Spanish emigrants, including four families, arrived.
    1776   Tule thatched roofs set on fire by flaming arrows; many buildings destroyed.
    1792-1794  Construction of present church  with help from master Mexican craftsmen; made of adobe with tile roof."
     
    Here's a detailed article (written 110 years ago):
    http://web.nationalbuildingarts.org/collections/clay-products/clay-tile-roofing/brief-history-of-roofing-tile/
    One could read about tile roofing all day.
    :|
    To the op, the answer is likely somewhere between maybe and yes.
    That's more than enough from me!
  8. Like
    glazenerd got a reaction from LeeU in Testing for clay origins   
    PD
    I have some historical knowledge, after retiring from 45 years of home building. There were several plants in the Us at one time, but most are gone because synethic materials have taken over the market. I believe the one in zflorida, and California are still operational there were brickyards in almost every state from the 1870,s until after WW2 because weight made it too hard to ship.many of those brickyards also made Terra Cotta roofing tiles. 
    Most all tiles made in North America were the classic Terra Cotta orange because iron disulfide is the most common iron source here. Some deeper orange and reddish colors came out of NY, Arkansas, Oklahoma, and Georgia because those areas have megnetite and hematite iron deposits. 
    One notable difference in historic tiles was the nail punch pattern, In North America, a round single center punch was used. Ital, France, and Spain used a square punch, until the more recent decades. European tiles were generally thinner because they could fire higher because of the iron, American/ Mexican tile was thicker and fired lower.  
    It is most likely locally made; and a good chance the brick yard that made it is long gone. Check with your local historical society. Pending the age; it could have been imported from Mexico as "Spanish" tile. The odds that it was imported are minimal. If it is a point of historic s importance: you could have a crushed sample analysis done and identify the iron source. 
     
    Tom. 
     
  9. Like
    glazenerd got a reaction from terrim8 in Purple Lustre Glaze Mystery   
    I have seen that purple before in crystalline glaze. Titanium reacts with iron\ zinc when fired in reduction to produce purple. I have gotten purple in oxidation using prescribed levels of iron and titanium. I would start an experimental recipe with 8% titanium, 3% iron, and 4-5% zinc: and reduce on the cooling cycle. I do not know the exact recipe, although by the run Nep SY is most likely the primary flux.
    Tom
  10. Like
    glazenerd got a reaction from Rae Reich in Testing for clay origins   
    PD
    I have some historical knowledge, after retiring from 45 years of home building. There were several plants in the Us at one time, but most are gone because synethic materials have taken over the market. I believe the one in zflorida, and California are still operational there were brickyards in almost every state from the 1870,s until after WW2 because weight made it too hard to ship.many of those brickyards also made Terra Cotta roofing tiles. 
    Most all tiles made in North America were the classic Terra Cotta orange because iron disulfide is the most common iron source here. Some deeper orange and reddish colors came out of NY, Arkansas, Oklahoma, and Georgia because those areas have megnetite and hematite iron deposits. 
    One notable difference in historic tiles was the nail punch pattern, In North America, a round single center punch was used. Ital, France, and Spain used a square punch, until the more recent decades. European tiles were generally thinner because they could fire higher because of the iron, American/ Mexican tile was thicker and fired lower.  
    It is most likely locally made; and a good chance the brick yard that made it is long gone. Check with your local historical society. Pending the age; it could have been imported from Mexico as "Spanish" tile. The odds that it was imported are minimal. If it is a point of historic s importance: you could have a crushed sample analysis done and identify the iron source. 
     
    Tom. 
     
  11. Like
    glazenerd got a reaction from Hulk in Testing for clay origins   
    PD
    I have some historical knowledge, after retiring from 45 years of home building. There were several plants in the Us at one time, but most are gone because synethic materials have taken over the market. I believe the one in zflorida, and California are still operational there were brickyards in almost every state from the 1870,s until after WW2 because weight made it too hard to ship.many of those brickyards also made Terra Cotta roofing tiles. 
    Most all tiles made in North America were the classic Terra Cotta orange because iron disulfide is the most common iron source here. Some deeper orange and reddish colors came out of NY, Arkansas, Oklahoma, and Georgia because those areas have megnetite and hematite iron deposits. 
    One notable difference in historic tiles was the nail punch pattern, In North America, a round single center punch was used. Ital, France, and Spain used a square punch, until the more recent decades. European tiles were generally thinner because they could fire higher because of the iron, American/ Mexican tile was thicker and fired lower.  
    It is most likely locally made; and a good chance the brick yard that made it is long gone. Check with your local historical society. Pending the age; it could have been imported from Mexico as "Spanish" tile. The odds that it was imported are minimal. If it is a point of historic s importance: you could have a crushed sample analysis done and identify the iron source. 
     
    Tom. 
     
  12. Like
    glazenerd reacted to Callie Beller Diesel in Troubles With Slip   
    Sieving will get rid of the lumps long enough to work with it for a session, but you’ll have to remix or resieve the next time you go to use the same batch.  
    +1 for either adding more dry material or leaving some out the night before to thicken rather than trying to adjust with Epsom salts. Having less water in the mix can also help your slip not shrink as much.
  13. Like
    glazenerd reacted to Min in Troubles With Slip   
    @Hannah Greenblott, sounds like maybe you just added too much that wasn't blended in well. At about the 2 minute mark in the video below you can see how little John Britt uses in his deflocculated slip to thicken it back up again. 
     
  14. Like
    glazenerd got a reaction from Rae Reich in Troubles With Slip   
    Hannah:
    premixed slip uses Darvan 7 or equal as a long chain deflocculant. This type of ionic polymer works by neutralizing sodium and magnesium ions. When you added Epson salts: you added magnesium strearate which disrupted that chemical suspension which caused flocs (clumps) to form. Adding sodium silicate, epson salts (magnesium) causes a chemical reaction. In the future, to thicken it- it is best to add dry powdered clay you recycled from throwing, dried slip or whatever source you can recycle from. 
    T
  15. Like
    glazenerd got a reaction from Hulk in UNESCO Cultural Preservation   
    UNESCO (United Nations) catalogues and records significant cultural art and artifacts- including pottery. The link below is for a remote village in Ukraine that does hand painted pottery. (Stunning) Follow the UNESCO links for a complete list of unique pottery from around the world.
    https://usa.mfa.gov.ua/en/news/open/id/76732 
    Tom
  16. Like
    glazenerd got a reaction from Rae Reich in Storing Crystalline Glazes   
    Brandon:
    The 50% frit content makes this glaze prone to hard panning- the 25% zinc does not help either. I will send you some glaze jelly- will fix you right up.
    T
  17. Like
    glazenerd got a reaction from dhPotter in Storing Crystalline Glazes   
    Brandon:
    The 50% frit content makes this glaze prone to hard panning- the 25% zinc does not help either. I will send you some glaze jelly- will fix you right up.
    T
  18. Like
    glazenerd got a reaction from Genboomxer in Another Newbie Playing with Native Soil   
    Gen- I will add SoCal to my list. From the color response you are dealing with iron disulfide. I would fire to cone 3, and check color response: then fire to cone 1- and check it again. I will assume you are after classic Terra Cotta. Once you determine the highest cone value verses color; you can then build flux additions around that cone to lower absorption. 
    T
  19. Like
    glazenerd reacted to Magnolia Mud Research in Stacking Glazed Plates   
    Make terra-sig from your clay body and apply and burnish the bottoms or foot rims.  Then you will not need to grind the surface after the firing.  
  20. Like
    glazenerd got a reaction from Rae Reich in Plain Porcelain with unwanted brown “flashing”   
    Sarah:
    I looked up your Super White: which is Grolleg kaolin based, but also uses ball clay as a plasticizer. Grolleg is about as clean as clay gets and fires high white; however using ball clay introduces contaminants such as magnesium, titanium, and iron. In this case it is not iron, but rather magnesium reacting with titanium. In addition, this body has higher flux levels which also play a role in creating the brown toasty color. Leave the plug out until 1100C, and do not allow pieces to touch each other, nor should you stack them. See test bar 4 below: which is high titanium, flux, with lower iron and magnesium.
    Tom
  21. Like
    glazenerd got a reaction from LeeU in Plain Porcelain with unwanted brown “flashing”   
    Sarah:
    I looked up your Super White: which is Grolleg kaolin based, but also uses ball clay as a plasticizer. Grolleg is about as clean as clay gets and fires high white; however using ball clay introduces contaminants such as magnesium, titanium, and iron. In this case it is not iron, but rather magnesium reacting with titanium. In addition, this body has higher flux levels which also play a role in creating the brown toasty color. Leave the plug out until 1100C, and do not allow pieces to touch each other, nor should you stack them. See test bar 4 below: which is high titanium, flux, with lower iron and magnesium.
    Tom
  22. Like
    glazenerd got a reaction from Benzine in Plain Porcelain with unwanted brown “flashing”   
    Sarah:
    I looked up your Super White: which is Grolleg kaolin based, but also uses ball clay as a plasticizer. Grolleg is about as clean as clay gets and fires high white; however using ball clay introduces contaminants such as magnesium, titanium, and iron. In this case it is not iron, but rather magnesium reacting with titanium. In addition, this body has higher flux levels which also play a role in creating the brown toasty color. Leave the plug out until 1100C, and do not allow pieces to touch each other, nor should you stack them. See test bar 4 below: which is high titanium, flux, with lower iron and magnesium.
    Tom
  23. Like
    glazenerd got a reaction from Hulk in Plain Porcelain with unwanted brown “flashing”   
    Sarah:
    I looked up your Super White: which is Grolleg kaolin based, but also uses ball clay as a plasticizer. Grolleg is about as clean as clay gets and fires high white; however using ball clay introduces contaminants such as magnesium, titanium, and iron. In this case it is not iron, but rather magnesium reacting with titanium. In addition, this body has higher flux levels which also play a role in creating the brown toasty color. Leave the plug out until 1100C, and do not allow pieces to touch each other, nor should you stack them. See test bar 4 below: which is high titanium, flux, with lower iron and magnesium.
    Tom
  24. Like
    glazenerd got a reaction from liambesaw in Plain Porcelain with unwanted brown “flashing”   
    Sarah:
    I looked up your Super White: which is Grolleg kaolin based, but also uses ball clay as a plasticizer. Grolleg is about as clean as clay gets and fires high white; however using ball clay introduces contaminants such as magnesium, titanium, and iron. In this case it is not iron, but rather magnesium reacting with titanium. In addition, this body has higher flux levels which also play a role in creating the brown toasty color. Leave the plug out until 1100C, and do not allow pieces to touch each other, nor should you stack them. See test bar 4 below: which is high titanium, flux, with lower iron and magnesium.
    Tom
  25. Like
    glazenerd got a reaction from Rae Reich in Purple Lustre Glaze Mystery   
    I have seen that purple before in crystalline glaze. Titanium reacts with iron\ zinc when fired in reduction to produce purple. I have gotten purple in oxidation using prescribed levels of iron and titanium. I would start an experimental recipe with 8% titanium, 3% iron, and 4-5% zinc: and reduce on the cooling cycle. I do not know the exact recipe, although by the run Nep SY is most likely the primary flux.
    Tom
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