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glazenerd

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  1. Like
    glazenerd got a reaction from MFP in Who wants to see an explosion, look here!   
    It's official: you are now a veteran potter.
  2. Like
    glazenerd got a reaction from Marcia Selsor in Important Ceramic Artists Who Should Be Known   
    My personal favorite- Taxtile Doat. - most crystalline glazers count him as the godfather of this speciality glaze.
    http://history.ucpl.lib.mo.us/results.asp?search=Doat%2C+Taxile+Maximin%2C+1851-1939
    check out the 4 foot wide porcelain bowl he threw in 1910. 2 assistants turned the wheel. 
    Help found the University Pottery (University City, Mo.) 1910. Proceeds funded the Woman's' Sufrage Movement.
    Teachers - he also wrote some of the earliest curriculum for Art Ed. 
    Have toured what is now called: University Museum.  
  3. Like
    glazenerd got a reaction from Bill Kielb in QotW: How do you feel about culture theft?   
    Been following this topic, but I know just enough about Japenese/Chinese/Korean culture to say something wrong. One of the many times I wish Baymore was around: these cultures were his speciality. Being a Westerner, I will add a twist to it.
     Modern technology has managed to put most of the worlds population onto a single stage/platform. The assimilation of culture that once took centuries, now only requires a mouse click. Marco Polo bought back porcelain pieces from China: and Europe spent 500 years trying to replicate them. Any potter can click Sung/Ming dynasty and start throwing in an attempt to duplicate it. The unfortunate side effect of instant knowledge, is the loss of culture and application.
     The old saying goes "imitation is the sincerest form of flattery."  Should the blog writer be offended or flattered that others are trying to imitate her culture?  Obviously some have hijacked strictly for ill advised sales promotions. Yet others love the work, love the culture, and are sincerely trying to imitate it.  Personally I think she should educate rather than reprove. It is a futile effort to chastise those who have no respect to begin with.
    thats my 5 cents  worth.  The extra 3 cents if for shipping and handling.
    Tom
  4. Like
    glazenerd reacted to Rae Reich in Giffin Grip 1984   
    In 1979, I paid $1000 for a catenary 12 cu ft hardbrick kiln and assorted shelves and glazes. 'Course, it had to be mapped, disassembled, hauled across town in an ancient pickup (stop loading when tires distort), bricks cleaned and reassembled. Oh, we were an energetic crew of potters and friends! 
  5. Like
    glazenerd reacted to Mark C. in Firing Schedule Variables   
    (Sorry Bill, I broke my two cup rule. Never answer questions until I finish the second cup.)
    if that coffee where stronger (fresh ground beans) only one cup would be nessacary.
  6. Like
    glazenerd got a reaction from LeeU in QotW: How do you feel about culture theft?   
    Been following this topic, but I know just enough about Japenese/Chinese/Korean culture to say something wrong. One of the many times I wish Baymore was around: these cultures were his speciality. Being a Westerner, I will add a twist to it.
     Modern technology has managed to put most of the worlds population onto a single stage/platform. The assimilation of culture that once took centuries, now only requires a mouse click. Marco Polo bought back porcelain pieces from China: and Europe spent 500 years trying to replicate them. Any potter can click Sung/Ming dynasty and start throwing in an attempt to duplicate it. The unfortunate side effect of instant knowledge, is the loss of culture and application.
     The old saying goes "imitation is the sincerest form of flattery."  Should the blog writer be offended or flattered that others are trying to imitate her culture?  Obviously some have hijacked strictly for ill advised sales promotions. Yet others love the work, love the culture, and are sincerely trying to imitate it.  Personally I think she should educate rather than reprove. It is a futile effort to chastise those who have no respect to begin with.
    thats my 5 cents  worth.  The extra 3 cents if for shipping and handling.
    Tom
  7. Like
    glazenerd got a reaction from Rae Reich in What’s on your workbench?   
    Controlling the rate of drying has been on my agenda for a few years now. Couple of years back I was mixing a wetting agent into porcelain in an attempt to control it: those who got samples know how badly that flopped.
    so I have been working on a spritz made mostly of organic/food safe materials. To date, I have extended drying time by roughly 30%. When I get up to 50% or so, I will unveil it. However, I have no laboratory rats to test toxicity on, so PM me if you want to volunteer to drink a cup or two. ( that was Westerner joke by the way).
    T
  8. Like
    glazenerd got a reaction from Bill Kielb in Firing Schedule Variables   
    Bill: results from Ougland & Brindley study on heat work.
    2192F (1200C) minimum further development of the clay body after this point. Minor decreases in absorption, along with minor increases in glass content. See chart below. Typical cone six ramp hold temperature for maturity.
    -----------------           ---------------------
    2192F (1200C.). Glass 62.   Silica 21.    Mullite 19
    2372F (1300C).  Glass 66.   Silica 16.    Mullite 21
    (Ougland & Brindley)
     
    Off topic,  Ron Roy emailed me: he is doing a work shop nearby in June. Looking forward to seeing my friend. 
    Tom
     
  9. Like
    glazenerd reacted to Min in Firing Schedule Variables   
    Tom, for the sake of clarity (for the newer potters on the forum) it would be a good idea to say this would be for a cone 6 firing. Thanks.
  10. Like
    glazenerd got a reaction from Bill Kielb in Firing Schedule Variables   
    If anyone ran measured effects of heat work, it would be Orton Sr.  He wrote several abstracts for American Ceramic Society, I will nose around and see what I can find. The other source would be Ougland and Brindley from the British Ceramic Society: "Effects of a High Temperature on Kaolinite"  I read that abstract, and quoted some of it in my threads. It has since been pulled down, sadly. 
    I have been pricing gradient kilns: and potters gasp at the price of an electric. Keep waiting for a good used one to come along.  From my observation pending kiln size: there can be up to 40F difference in a large chamber. Years ago I started mixing my crystalline glazes via PH meter. I raise the PH in cold spots, and lower it in cold spots: works fairly well. 
    I would put conduction up to 2000F, and radiation there after. 
    Edit add: If Edison did not have Telsa: his inventions would have been few.  IMOIMO
    Tom
  11. Like
    glazenerd got a reaction from LeeU in QotW: What ceramic skill do you wish you had more training in?   
    Lee: let me give you an example of being me.
    YOU form your favorite stoneware clay and notice how pliable it is, how it takes texture, how fast it dries, and how plastic it is.
    i form the same clay and: 80/10/10, with 8.2CEC,  potassium body flux, with 30% plastic materials. 
    You have much more fun than I do    But TY.
  12. Like
    glazenerd got a reaction from LeeS in Vitrification and Glaze Fit Issues with Cone 10 Glacia   
    Lee:
    your option 2 will work. Powder down your reclaim: you only need 500 grams. Make 4-100 grams test samples. 
    Bar 1 add 5% Nep Sy. Bar 2 Add 10%  Bar 3 15% and Bar 4 20%  all four are flat tiles. Fire them flat on a kiln washed shelf to avoid plucking. Then run absorption test on each one- be sure to note on each bar the Nep Sy addition. Whatever level produces 2% or under absorption level-use that to fix the rest.  You only need to do this test once: assuming all your reclaim has had the same prior results.
    From this point, weigh out dry reclaim in bulk: do not need to powder it down.  EX. 10,000 grams of dried reclaim x 10% Nep Sy = 1000 gram flux addition. From this point, slurry it down as usual. Or pug..  
    Sounds like operator error at the factory!  Although I hear more and more instances of clay misbehaving. Not impossible they dug through a vein at the mine with much lower sodium content- Custer went through that in the 90's. There are some ball clays that have changed, as well as some fire clays- it happens. Clay supplier on the East coast has been having tackiness issues, drying issues. From my testing they have dug through a vein of smecite deposited in the ball clay field.
    Tom
     
  13. Like
    glazenerd got a reaction from Rae Reich in Hudson River Clay   
    If no one else will, then I will post a line from the Tina Turner classic
    "Proud Mary keep on Rollin".    And you should be proud. Figuring out a recipe is not easy.
    T
  14. Like
    glazenerd got a reaction from Min in Vitrification and Glaze Fit Issues with Cone 10 Glacia   
    Lee:
    your option 2 will work. Powder down your reclaim: you only need 500 grams. Make 4-100 grams test samples. 
    Bar 1 add 5% Nep Sy. Bar 2 Add 10%  Bar 3 15% and Bar 4 20%  all four are flat tiles. Fire them flat on a kiln washed shelf to avoid plucking. Then run absorption test on each one- be sure to note on each bar the Nep Sy addition. Whatever level produces 2% or under absorption level-use that to fix the rest.  You only need to do this test once: assuming all your reclaim has had the same prior results.
    From this point, weigh out dry reclaim in bulk: do not need to powder it down.  EX. 10,000 grams of dried reclaim x 10% Nep Sy = 1000 gram flux addition. From this point, slurry it down as usual. Or pug..  
    Sounds like operator error at the factory!  Although I hear more and more instances of clay misbehaving. Not impossible they dug through a vein at the mine with much lower sodium content- Custer went through that in the 90's. There are some ball clays that have changed, as well as some fire clays- it happens. Clay supplier on the East coast has been having tackiness issues, drying issues. From my testing they have dug through a vein of smecite deposited in the ball clay field.
    Tom
     
  15. Like
    glazenerd got a reaction from Benzine in Vitrification and Glaze Fit Issues with Cone 10 Glacia   
    Lee:
    your option 2 will work. Powder down your reclaim: you only need 500 grams. Make 4-100 grams test samples. 
    Bar 1 add 5% Nep Sy. Bar 2 Add 10%  Bar 3 15% and Bar 4 20%  all four are flat tiles. Fire them flat on a kiln washed shelf to avoid plucking. Then run absorption test on each one- be sure to note on each bar the Nep Sy addition. Whatever level produces 2% or under absorption level-use that to fix the rest.  You only need to do this test once: assuming all your reclaim has had the same prior results.
    From this point, weigh out dry reclaim in bulk: do not need to powder it down.  EX. 10,000 grams of dried reclaim x 10% Nep Sy = 1000 gram flux addition. From this point, slurry it down as usual. Or pug..  
    Sounds like operator error at the factory!  Although I hear more and more instances of clay misbehaving. Not impossible they dug through a vein at the mine with much lower sodium content- Custer went through that in the 90's. There are some ball clays that have changed, as well as some fire clays- it happens. Clay supplier on the East coast has been having tackiness issues, drying issues. From my testing they have dug through a vein of smecite deposited in the ball clay field.
    Tom
     
  16. Like
    glazenerd reacted to Min in Vitrification and Glaze Fit Issues with Cone 10 Glacia   
    Since the clay is getting water logged after firing to cone 10 and according to Clay Planet that porcelain should have an absorption of <1% (from the description of the pugged version of that clay),  I would conclude the absorption is much higher than what is posted. There wasn't enough flux added to the mix. I would measure the absorption yourself then contact Clay Planet with your result plus the batch number and hear what they have to say. I would hold off on trying to get a glaze to fit until you have the body itself sorted out. 
  17. Like
    glazenerd got a reaction from GreyBird in Hudson River Clay   
    Mary:
    in my testing, I noticed Hudson clay is extremely sensitive to application thickness. Also noticed color shifts when I increased potash content. Soon as I get time, going to slurry down a sample and spray it on.
    Tom
  18. Like
    glazenerd reacted to GreyBird in Hudson River Clay   
    Its funny how things work out sometimes... I had posted a photo from a book a while back which pictured a "rust red"platter. I had to take the photo down as it was copyrighted, but the discussion talked a lot about obtaining the red I was looking for that I saw on that platter. I had given up on the idea after many failed tests. And subsequently moved on to develop the Hudson River Clay glaze. The last tile I pictured here in this post showed some really great rust red blooming from the dark glaze. I fired that in my test kiln and matched the heat rise and fall of my large kiln, or so I thought. Until I went to run these two mugs when I noticed that after it reached temp I had the numbers put in wrong and the kiln actually cooled much quicker than it would have in my large kiln. So I fixed the error and let the cups fire with a slow cool of 190° per hour to like 1490 the let it cool the rest naturally. The results were a rust red alternating with shiny black very similar to that elusive platter red I was trying to achieve. I do have a question in all of this... Notice how the clay appears stained reddish from about 1/2" from the bottom up. I'm sure the cups were clean when they went in and not sure where this discoloration is coming from. could it be that the Iron soaked from the glaze through the clay? Maybe if I cool at 200° per hour or let it cool naturally next time it'll have less time to soak through?


  19. Like
    glazenerd reacted to GreyBird in Hudson River Valley clay   
    Yes! Go to Croton Point, park in the big parking lot facing the playground. Walk in past the playground parallel to the river. You'll be walking South. When you come to the end of the field you'll see a path/dirt road that goes up and to the left a bit. Follow that up about 100 yards and you'll see a path on your right which leads down to the river. Now just keep walking South along the river and look to your left. There are many places where trees have fallen over and you can see the clay entangled in their roots. Also where the walls of the river get steep and high you will see clay there. You'll need to check the tide chart and go at low tide. I imagine if Croton Point is not close to you you can probably find the same anywhere that you have the river walls exposed.
    PS... I had the clay analyzed and it came back surprisingly clean  
  20. Like
    glazenerd reacted to Hulk in Got clay?   
    yep, as a newbie, trying some different clays seemed a good idea - the next break after 100 lbs is 500 lbs, so went with 100 each of several clays in my first "big" order; for glaze mats, went with 50 lb bags of what I thought for sure would be useful, e.g. silica, epk, neph sy… Perhaps by next order will have figured which frit(s) to bulk up on; so far, looks like glazes with frits 'have better. There's another cost analysis topic...
  21. Like
    glazenerd got a reaction from Babs in Calcined Kaolin   
    Kaolin can have up to 15% natural shrinkage! most of which comes from combined molecular moisture. Specifications for natural clay are not expressed by "shrinkage" as is the case with blended clay bodies.LOI (loss on ignition) is used to express the loss of weight in comparison to the total weight. EX: LOI is 13%  so for ever 100 grams of material, 13 grams will be lost when heating up to bisq temperatures. Organic materials, lignite coal, and molecular moisture are examples of materials lost on ignition.
    The primary reason kaolin is calcined (EPK) is control excessive shrinking of material during firing; up to bisq temps. Materials can flake off or crack when there is excessive LOI. Calcining does not effect material characteristics, nor does it lower melting temps.
    T
  22. Like
    glazenerd got a reaction from Callie Beller Diesel in QotW: What skill outside of pottery making has helped you most in your pursuit of making pottery?   
    After working on and building a 1000 plus houses the last 45 years: carpentry and mechanical skills. Most know I only make and sell custom tile designs. That starts on my AutoCad system as a drawing; which I can print up to 24 x 36". From there it goes to the scroll saw, and individual pieces are cut out of 1/2" plywood. Next I cut 1.5" strips of metal 16ga.) on my brake. I either bend the folds on my brake, or heat it and bend to form circles, arcs, concave,convex- whatever. The metal is then stapled 1/4" x 1" to the edge of the plywood: and now I have a die. The only thing I hand cut is a medium rare steak: the clay gets stamped. 
    T
  23. Like
    glazenerd got a reaction from roderick in Questions about plasticity and natural clay   
    Tom
  24. Like
    glazenerd got a reaction from Hulk in QotW: In terms of your pottery work, where do you seen yourself five years from now?   
    Liam:
    i agree, Mark has an inspiring success story in the pottery biz. After 45 years in carpentry, I am aware of the time, energy, and sacrifices he made to build it. Pottery is unique; full time, part time, weekenders, full time hobby, to monthly dabble. My only intention starting out was to "play" with crystalline glaze, until I accidentally fell down this very deep rabbit hole. Rabbit holes are also unique, but also common in pottery. To answer the QotW: I do not want to make any pottery plans: because it is the only area of my life that is not. I find the unplanned happy accidents of discovery a relief from a lifetime of calculations.
    T
  25. Like
    glazenerd reacted to Hulk in Slow bisque kiln help   
    Hi Tstst!
    Regular contributor Glazenerd has posted bisque schedules here, with some details on why the holds ...looking...
    Overview
    Some specific defects; see "Cone 6-10 Firing Schedule for dark or red bodied clay bodies."  in last post
    See also
     
    Perhaps someone familiar with your clay can add more - hope the above links are a good start? There are several others threads on the subject here as well.
    My kiln is fully manual, so I'm watching for the critical ranges and fiddling the switches to get the slow down (holds)...
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