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About PeterH

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  1. Worked example at Glaze Chemistry Basics - Formula, Analysis, Mole%, Unity, LOI https://digitalfire.com/article/glaze+chemistry+basics+-+formula%2C+analysis%2C+mole%%2C+unity%2C+loi I assume that you are familiar with the Seger Formula, and the advantages of ignoring the relative masses of the molecules when thinking about glaze structure. I've not seen %m before, but it looks like it is a single-column alternative to the Seger Formula when the latter's three-column structure doesn't make sense. For example: if a 'flux' is refractory at the firing temperature, or there is boron
  2. Just to mention turning boxes where you mainly turn wet/setting plaster against a profile. This is FIGURE 6.5.1-E Plaster turning box with a profile of a vase to be modeled. From Forming Techniques for the Self-Reliant Potter https://tinyurl.com/y5y6keh9 This is a wooden frame which is fitted with a metal shaft that can be rotated by a hand crank. It is used in combination with a profile. The metal shaft is first prepared by wrapping it with paper or cloth, and providing it with a metal pin. The paper prevents plaster from sticking to the shaft, and the pin is fixed so that i
  3. Are you involved in the waxing process, which I believe to be usually carried out while the pot is still warm from the firing? https://domainegeorgia.wordpress.com/kvevri/kvevri-lining/ If you are "delivering" unwaxed pots can you help by pre-heating the pot in a warm (portable?) kiln? http://winemaking.winetrailtraveler.com/2014/08/09/preparing-our-qvevri-coating-the-interior-with-beeswax/ Winemakers that purchases qvevris that have not been waxed should heat the qvevri before waxing. They do this by building a fire in a pot and lowering into the qvevri to heat the inside. We decided
  4. That looks a really interesting programme to be associated with. PS To my surprise it seems that spiral ribs on the inside of fermentation vessels are potentially useful. Passive wine macromixing from 3D natural convection for different winery tank shapes: application to lees resuspension https://media.proquest.com/media/hms/PFT/1/VDuHH?_s=iiT5MlyJGUtjIN33LtiG%2FoO6Ioo%3D
  5. I'm not pushing the idea, just mentioning it for 'compare and contrast'. I think that a rough interior would be unacceptable: as it breaks with tradition, and must hinder the important seasonal cleaning. I've no idea of the likely effect on the wine, but it must make any convection currents near the walls more turbulent. Presumably smoothing/trimming the interior might be possible when the form is leather-hard, although as you say access is limited. PS There are a pittance of qvevri references in the How to beginning using earthen pots for wine making thread. - One document is now
  6. I was reminded of an old French tradition for making large pots: https://deborahsilver.com/blog/tag/handmade-garden-pots/ This method of making large pots with wood armatures wrapped in rope is a centuries old technique. The form begins with a series of wood verticals that describe the height of the piece, and the diameter of the top and the bottom. Multiple wood ribs that describe the overall shape of the pot are fixed to the central verticals. Keep in mind that the pots are made top side down. Heavy rope is carefully wrapped around the wood ribs. The ribs and the rope crea
  7. Let's try that again. Can you confirm that we are talking about 15% linear shrinkage? If so, lets say we want to finish with a cube of 1" side, volume =1x1x1 cubic inches Using the calculator from How and Why To Make A Shrinkage Measure https://www.ceramicartsqld.org.au/index.php/component/k2/how-and-why-to-make-a-shrinkage-measure So the volume of the wet cube is 1.18x1.18x1.18 = 1.64 cubic inches PS The calculator uses 1.18 = 1/(1-0.15) rather than 1.15 as the shrinkage is 15% of the wet size rather than the dry size.
  8. Maybe I'm getting confused between linear and volume shrinkage. Shouldn't that be 21.65x1.15³ = 32.33
  9. https://ceramicartsnetwork.org/ceramics-monthly/clay-tools/making-clay-tools/tips-and-tools-extruder-conversion/
  10. Perhaps just avoiding thread drift, has anybody tried this? Which seems to have been in Nelson’s A Potter’s Handbook. The Student and Teacher’s Thixotropic Clay http://janestreetclayworks.com/2011/03/05/the-student-and-teachers-thixotropic-clay/ NB Most important thing about thixotropic clay DO NOT PUT IT INTO A PUG MILL, OR OTHER COMPRESSION MACHINES. It will break even the strongest gears.
  11. In case it stirs your memory Freely available, but not cheap (change location and currency) https://www.bookfinder.com/search/?full=on&ac=sl&st=sl&ref=bf_s2_a1_t1_1&qi=DPUGysRcr1ZO3LIKrUsJIavjYUg_1497963026_1:2:4 ... but the shop seem to have a special offer https://ceramicartsnetwork.org/shop/making-marks/
  12. @Prateek And another one, making a jolly mold in https://pureandsimplepottery.com/pages/jiggering Looks fun but messy
  13. Thin pickings: Jiggering in https://ceramicartsnetwork.org/wp-content/uploads/sites/6/2015/06/Ceramics_Monthly_oct85_cei1085d.pdf P16- in thesis https://scholarworks.rit.edu/cgi/viewcontent.cgi?article=2470&context=theses If you have access (I don't) Mold Making for the Jigger by Bill Campbell Ceramics monthly June/July/Aug 1987
  14. If you are meaning postings like https://tinyurl.com/y2opgn4a Then "flux" seems to refer to a Mayco flux glaze https://www.maycocolors.com/index.php/colors/mayco-flux
  15. You might find some information in the thread Oil based "plasticine" clay recipe
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