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glazenerd

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Posts posted by glazenerd

  1. Granular Magnetite (iron) at 2%.  From wet clay calculate 20% as water. 10lbs minus 20% water(2lbs) = 8lbs. Dry x 2% granular Magnetite. Judging from pic- 20 mesh speckles.  Make a 500 gram test batch and fire as a tile with usual glaze to judge speckle population. Add or subtract as per personal preference. Iron will be safer in your case given kiln location: granular manganese can fume. 

  2. Never had an instructor: then again I never intended to go down the rabbit hole this far either. I noticed early on in another forum where I lurked mostly: there would be ten different answers to one question. I understood that application and style could vary from potter to potter: but never made sense on the chemistry end of the equation. So I made the decision early on to seek out information by those with PhD behind their names. Oddly enough, found variance there as well- who knew? If I had a mentor; that would be Ron Roy: who I had the pleasure to spend three days with at NCECA in KC (2016). We email back and forth to this day. I have been asked several times to do classes in St. Louis- to date I have always declined. My wife, siblings, and two friends even know that I am involved with clay. Has always been my private sanctuary: and never discuss it locally.

    Tom

  3. Oddly enough: I would like to spend a day unseen in a corner, watching a newbie throw their first form, open their first kiln firing, or sell their first cup. The joy and excitement is contagious. Would have loved to spend a day with W.G. Lawrence (Phd@ Alfred) and pick his brain. Same for Orton Jr, Koppatchu, Horton, and a few others who laid the foundation on which modern pottery is built. 

  4. Sbsoso- welcome to the forum.

    You did not State clay body type: but I will go with porcelain. When doing production: not a bad idea to keep 25lbs from the previous lot to compare to the new lot if problems arise. No problems before, and now problems means the first stop is to check with supplier if others have reported issues. Like potters, clay manufacturers shop for low prices: which sometimes creates issues. You have a plasticity issue which you can only resolve by adding water. Adding water does not increase plasticity; just moves the body closer to its liquid limits. Adding water will also increase drying issues such as warping. Your plasticity issue is caused by one of two things: the % of plasticizer has been lowered, or the plasticizer (ball clay) has lower plasticity properties. The second is Nep Sy being used as a body flux. Nep Sy has 14% soluble salts that can migrate: which can cause rapid dehydration of water. Sodium is hydrophobic- fancy word for- not fond of water. Again adding water compounds the problem by allowing further migration of soluble salts. 

    As others stated: de-airing pugmill has zero influence. All a de-airing pluggers does is remove the air between clay particles which speeds up the transfer of negative particle charges. De-airing has zero influence of the actual chemistry of the material.

    Tom

     

  5. 32 minutes ago, Mark C. said:

    (Time for the young people to step in. )

    I wish some young potters would step in around here but as of late there are no takers. Seems nobody wants to be a full timer anymore around here.Might be a sign of the times.

    Even at shows in other nearby states I never see young potters coming into this field.

    About half the tradesmen around here retired, or moved south. Of the other half: 90% are 45+ years old. Everyone once in awhile I see 20-30's at the lumber yard. Local colleges and schools ceased trade classes over a decade ago. Most schools have dropped art classes. Local community college cut pottery classes way back. State college still has a strong pottery criteria; but heavily focuses on sculptural work. 

    Prez: that would be an interesting question: do your local schools/colleges still teach pottery courses (historical, not Covid related) Changes in focus, technique etc.  You get the drift ; phrase it as you wish. Curious to see changes.

  6. Like Min; moving is in my near future- next year or so. Will have to decide which kilns to keep, which to sell; along with other equipment. I built a 26x44 work studio over a decade ago that is stuffed with equipment and supplies; most of which will not go with me into my golden years. Truthfully, I wrestle with just walking away all together. Would not miss the glaze so much as I would miss the clay-chemistry.

    Tom

  7. Harvesting and processing wild clay is an emerging trend; more popular than most realize. Many are processing their own silica, fluxes, etc from wild sources. Natural basalt is gaining popularity for some amazing reds. The best looking celadon I have seen is processed from natural materials. Certainly not profitable or suitable for production: although some are heading that direction. Hunting wild clay is somewhere in the panning for gold category: hoping to find the perfect pit. Firing crystalline; absolute No for me- cannot give up modern kiln controllers.

    Tom

  8. Min: the first mention of slow cooling I seen was in an ACERS journal by Edward Orton, Jr. (The cone guy) in 1908. The mid 1970's is when I have noticed changes in modern pottery. However, I also noticed detrimental effects of technology in the last two decades. Modern kilns, glazes, and premix clays makes pottery easily accessible to any and all: which is a good thing. However, the ease of operation does not require the user to acquire any basic working principles of functional or food safety guidelines. We have all seen the end products on EBay and art fairs. 

    That said: technology has opened doors on previously extremely challenging techniques and glazes. I spent all of one month attempting to fire crystalline glaze in an old kiln with a sitter before I quickly realized I was not spending 8 hours babysitting it. Kiln controllers rank high on technological improvement list. Anyone who had or played on a kick wheel: would say the same about an electric wheel. I have been playing around with self glazing clay bodies----one of these days....

    T

  9. Min: the difference between us doing a triaxle and them doing a triaxle: they have PhD behind their names.  Which comes back to the thread's premise: they have lab equipment of measure: we do not.

    Bill- late 60's into the 70's. 

    A standard cone 6 porcelain is 30% KnaO, and cone 10 is 25% KnaO. Heat work being the offsetting factor. 

  10. 7 hours ago, Bill Kielb said:

    I never could find out why 6, not five, or four or seven? And energy, only anecdotally.  Cones are a great one but credit Hermann Seger.   I like all those examples though, hidden game changers right in plain sight.

    U of I study found that KnaO was completely melted/spent at 2190F. Above 2230F =/- cristobalite begins to form. In a clay body 3/8-1/2" wall: potassium begins to melt (fluid) at 2044F and sodium 2012F. The combination of these factors is the basis of cone 6 firing target. Ougland & Brindley (British Ceramic Society) found glass content at cone 6 was 61% and glass content at cone 10 was 66%. Mullite at cone 6 was 19% and mullite at cone 10 was 21% Their study was based on a triaxle blend of 1/3 kaolin, 1/3 KnaO, and 1/3 silica. (porcelain).  So now you have the why!

  11. Bill: cone 6 rose up in the early 80's because of power shortages/costs. Ceramics/pottery uses extensive technology; but we only end up seeing the consumer product results. Mines use slurry technology, magnetic separators, and power sievesthat do tons per hour. Orton cones are based in technology (chemistry). The pentameter Laguna uses ensures clay remains reasonably consistent. K26 brick, magnesium insulation, advancer shelves, controllers, relays, and thermocouples.

    T

  12. TY Min.  A couple of Doctors in the States have said they do not work. However, States, Counties, and hospitals have been asking the public to bring these masks in if they have them. To my knowledge, the mask worn in hospitals are N95, unless they are using the full level 4 bio suits. Certainly some mixed messages State side.

  13. Like Roberta: my wife and I live on acreage- surrounded by more timber and farmland. Very thankful we do not live in a dense urban area. I retired from home building almost 2 years ago, I still do high end finish work for high end contractor friends. I work alone mostly, rarely deal with people face to face: and have work for several more months. I am fully aware of my fortunate situation: so my concerns are for others who will be hurt by the uncertainty of these times. My mother is 87; my brother has her for a month, then my sister for a month: then me. She will stay with one of us until this storm passes. On the bright side: many potters have masks or respirators if those needs arise. 

  14. I started out of the gate making and firing crystalline glaze: which also meant making my own glaze. From there it naturally evolved into making my own glazes; including my own versions of temmoku and others. The first ton of clay I purchased, then started making my own- later buying a pugmill. Currently, I use R2 porcelain that I specifically developed to promote crystalline growth. I make my own suspender and brushing medium: that Britt named glaze jelly. Made my own tile setters, and other kiln furniture. I prefer to explore and learn.

    T

  15. Marcia:

    Speaking of crystalline glaze- I read a thesis paper on crystalline glaze written by a student at SIU-C in 1973. As a historical perspective: 1973 was 25 years before any formal books on crystalline glaze was published ( Macro Crystalline Glaze by Peter Isley) I have read it several times: the insights and theorem are well within the boundaries of modern crystalline chemistry. The author of this thesis paper was YOU.

    T

     

  16. A recent thread on culture made me think about periods of art history. Being an arm chair historian, I often go through the history of potters before us: Adelaide Robineau's Scarab Vase comes to mind. Historians put art (including pottery) into periods: Medievel, Renaissance, Baroque, and Neo-Classical for instance. (Google "periods in art history"- you will find them)  Each period in recent history lasted 100-200 years: the current period began in 1800. So if periods last 200 years, that would mean beginning in 2000, a new period should have begun.....but it has not! 

    Qotw : what name would you ascribe to the current period of art history that began in 2000? 

  17. 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

  18. 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

  19. 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

  20. 23 hours ago, liambesaw said:

    There will be plenty of time to retire when you're dead.  

    I spent the last 45 years telling myself that, not sure I agree these days.

    like most here, my life was the typical series of following schedules to earn a living. Planning, plotting, and projecting the path ahead. I find myself curious about not going to bed in order to get up at regulated time. I am curious to know what it is like not to meet deadlines, keep appointments, and plan for months ahead. Not sure I even know what "living for the day" means. I have held many titles over the last 45 years, most of which have little meaning: I find "couch tater" appealing lately.

    T

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