Jump to content


  • Content count

  • Joined

  • Last visited

About JBaymore

  • Rank
  • Birthday July 19

Contact Methods

  • Website URL

Profile Information

  • Gender
  • Location
    Wilton, NH USA
  • Interests
    woodfiring, Japan, Chado, Iaido

Recent Profile Visitors

406,293 profile views
  1. Finished loading Fushigigama at the college this Fri., Sat., and Sun.  Already exhausted from being in charge of that operation.  Next.... in charge of the firing coming up starting Thursday morning and ending by about midnight Sunday night.  Will be right there all but from midnight until 6 AM each day, Fri, Sat, Sun..

  2. Tom, Yes.... but the point of the starting question from a hobbiest is that he is thinking of working on developing a clay body as a solution to not having a local supplier produce a body that works for him. And cost is a concern. So investing the kind of time it would take to really understand this stuff (time is money) is time away from actually making stuff. If he has that kind of techie interest, fine. But there likely are solutions that would make more sense for most folks. (There is also the equipment and health risks issues to address.) Mere mortals do not typically go into the depth concerning developing clay body understanding that you have. best, ........................john
  3. Look at the time and years you have put into working to understanding clay bodies already. best, ......................john
  4. Just by way of background, I use multiple clay bodies for various types of pieces... some are my own recipes I mix, some are commercial, and some are commercial that I then modify. I do have a decent batch clay mixer (over 40 years old now) with a good ventilation setup on it....which certainly helps. (To buy that equipment now would cost many thousands of dollars.) One clay body I use (in smaller amounts) I have shipped literally all the way across the USA from the other coast. No one else makes anything like it. The shipping is WAY more than the cost of the clay. Even given that.... clay is cheap (including the shipping costs). As far as clay/glaze fit goes, altering glazes is far easier than developing GOOD clay bodies. best, ..........................john
  5. Remember that your clay is actually close to the cheapest part of your operation. It is your TIME that is important and valuable and expensive. Mixing clay,.... heck even reclaiming clay.......... is very time intensive. Even with decent equipment.... and that equipment will cost you a lot of money. Money that will become part of your "clay cost" anyway. As a hobbiest, do you want to spend the time you have to devote to the hobby in mixing clay, or improving your forming and decorating skills and making pieces? Tyler and Mark are right on.......... try to find a commercial body that works and then tweak glazes to fit. best, ....................john
  6. You are remembering that correctly, Tyler. best, ........................john
  7. Reducing thermal conductivity

    Handle-less cups.... the Japanese have a name for them.... yunomi. They have a foot ring and are sized so that you grip them between the thumb on the lip and the middle finger on the footring....... solving the "hot on the hand" issue. I don't doubt that working this thru on a 'high tech' level that some solution to the conductivity issue is POSSIBLE.. ...... just that it is not practical .... particularly at a reasonable price point. Smooth ceramic shell over insulating material and so on. Mugs for $1000 each. best, ..........................john
  8. Flux Formula Limits For Porcelain

    Remember, that most of the 'famous' Chinese porcelains were thrown very thickly....and then trimmed at the dry state (yeah.... dust city) both inside and out with sharp metal tools to get them thin. Saw this process first hand when I was in Jingdezhen. best, .................john
  9. Absorption

    Test without glaze. If the glaze has a single pinhole that goes to the body, or if the glaze is crazed....... any liquid inside it will reach this body. Then ... if the body is not impermeable to liquid passing thru......... it will eventually weep/sweat/leak. If you plot the percentage absorption on a graph relating % absorption to firing cone you are going to get a sort of a "curve" for any clay body. It is the shape of this curve that tells you a LOT about how that body will perform relative to absorption over a certain firing range. A steep slope in any area tells you that a slight change in the cone the work is fired to will have a DRAMATIC change in the absorption of the body. A more gradual curve slope tells you that there is more tolerance for firing variations. Usually the curve plotted is not in any way symmetrical..... meaning that the slope of the line on one side of the minimum absorption point will not reflect the shape of the line on the other. As a clay gets overfired, the % absorption will increase a bit as the body "fizzes" and voids start to show up. This side of the curve usually is a less steep slope area. (Of you also plot the strength of the clay in this overfired area...... the strength goes down steadily.) The steeper the drop to the minimum on the lower side of the line, the more specific the firing cone of the clay is. Clay bodies that are intended to be vitrified typically have a reasonable firing range of about 3 cones max. No such thing as a cone 6-10 body... and the new trend stating "cone 4 to 10" should likely be challenged legally as "misrepresentation" and not meeting the dictates of the law of merchantability. best, ...........................john
  10. Raku Proposal For School

    Yeah... Steven's work is wonderful. He is THE guy for American raku. See his couple of books on the subject. Lots of solid information in those. The usual and main goal in post fire reduction is to reduce any materials that are available to be reduced and also hot enough to be reactive, and to impregnate the porous body with carbon compounds. The more physical space around the object to be reduced in a container, the more AIR there is in there to start with. The less tightly sealed the container is, the more air leaks into that container. To create good fuel rich reduction, air is your enemy. The more air... the more fuel you need to get consistent reducing conditions. The more fuel burning, the more flame and smoke. Great for drama and pictures.... for other things.... not so much. So the basic tenets of using the minimum burnable material to get the job done is small tightly sealable containers, one object per container, select the container to just fit the particular object, make sure the piece is going into that container at the correct temperature for the goals, and then not opening the container until the piece is cool (no quenching or very "late" quenching). Follow this above and a relatively tiny handful of shredded newspaper or sawdust or hay or the like will create a wonderful level of reduction and carbonization. Surprisingly little material. While it is a little sensitive an analogy given recent events, most people di post-fire reduction in raku like using a shotgun. Blast enough pellets in the direction of the objective and you are bound to hit something. To reduce the smoke factor, you wand to use a rifle. Single bullet well aimed. Hope this helps. best, ............................john
  11. Bad Habits with Manganese

    My big questions is WHERE did you learn about the toxic qualities of manganese? Let's start there to see if what you learned is accurate. best, ....................john
  12. Raku Proposal For School

    Tyler G, For hair coverings ..... non-synthetic fabric (cotton, wool, etc.) baseball cap (brim backward to clear face shield) or a tightly tied 'scarf". You can also get fireproof welders caps and "head coverings". We've not used respirators, because we do very "smokeless" post-fire reduction. All that excessive smoke and flame is dramatic.... but not necessary to get results and is also bad for people in the area and the environment. Watch my dear friend Steven Branfman do raku at his studio....... almost no smoke at all. Plopping a dozen pieces or so all in a big garbage can half filled with combustibles is not the way to go. If you feel the need for respirators, I'd says a HEPA filter stacked on a chemical one. Likely well more than one 'threat' in that smoke. There are lots of "safety equipment" companies. Any welder's supply can get you most everything you need. Here's the type of leather coats we use (stocked in multiple sizes): https://weldingsupply.com/cgi-bin/einstein.pl?PNUM::1:UNDEF:X:30WC-L best, ..........................john
  13. Great news! best, ......................john
  14. Raku Proposal For School

    When I do raku with my college level students, the ones pulling pieces and the ones working a can lid are both wearing a leather welder's jacket over a metalicised Kevlar long apron, leather welder's gloves, leather welder's leg spats (below the apron), leather shoes, and a full face shield over some form of non-flammable hair covering. I've seen all sorts of raku "horror shows" out there. I once was on the wrong side of a student raku error myself about 35-40 years ago. 3rd degree burns. Burn unit a the hospital.... lots of treatments for months. No fun. best, ...........................john
  15. Yup........ last woman or man standing: https://www.brainyquote.com/quotes/quotes/c/calvincool414555.html best, ........................john