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PeterH

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  1. Sorry, I don't seem to have made myself clear. I'm thinking of a power-side that consists of - 3 x 208V elements - a power relay for each - the complexities/cost of a transformer. Seems likely to be as least as simple in the boxes as Neil's 1st & 2nd options to fix the 250V safety issues, and would presumably allow per-zone control if required.
  2. Have you tried an indian-ink test? Easy enough to wipe off if there are no cracks. My first crackle glaze was pre internet and I very much had to guess the recipe. Came out without a crack in sight. Thought well I've got the indian ink so lets see, lo and behold lots of crackle.
  3. Would a 208V 3-phase to 208V single phase conversion have any attractions? Need a big transformer of course.
  4. I have a very imperfect recollection of an idea that might be repurposed to help. I think somebody needed to remove pots from the bat "early" to avoid drying issues, but was distorting the pots when doing so. The solution was to put high-wet-strength paper (teabag paper) on the bat before throwing the pot. When the pot was dry enough: wire-cut under the paper and then pull on the paper to slide the pot off the bat without touching it. If the OP is dead set against bats, maybe paper could be used as a partial substitute? PS I seem to remember the teabag paper was available in 6" rolls (or was it squares). No idea of current availability. ... well at least somebody sells it https://www.thatscrafty.co.uk/thats-crafty-surfaces-tea-bag-paper.html https://www.vycombe-arts.co.uk/onlineshop/prod_3687465-Tea-Bag-Paper.html ... most hits seem to be for huge rolls of ill-defined product for commercial use https://tinyurl.com/5x2yt4sj PPS Obviously there must be a knack to get enough clay under the paper before you start throwing.
  5. So is it likely that both the new and the (rewired) old kiln could share an (installed to code) NEMA 6-50R socket? ... really what should be considered/needed for house re-wiring for both kilns, if the rewired one will be 10KW at 240V (~42A). [To be confirmed when more details emerge.]
  6. My thinking was that the 48/1 -- on the plate about replacement elements -- was consistent with 3 x 208V elements which -- if wired in parallel -- would be a 48A single-phase load giving 10KW. On the other hand I read the main plate as saying 3-phase (PH/HZ 3/60). If the plug was factory-installed it is highly likely to be within code (in some context). My knowledge of 3-phase practice only goes as far as knowing √3 is a magic number, and 16*√3 = 27.7
  7. Just sharing my confusion about US power supplies. All NEMA 14 devices offer two hots, a neutral, and a ground, allowing for both 120 and 240 V when supplied by split-phase power, or 120 and 208 V if the supply is three-phase. Might we be talking about a 208v 3-phase kiln? 3-phase would imply 3 208v elements each generating 10000/3 watts. For each element i=W/V = 10000/3/208 = 16A per phase. So 48A in total.
  8. Is this "Laguna MS-29 Clear Bright Glaze",? If so in https://www.axner.com/lagunams-29clearbrightglazedrysoldperlb.aspx points to Laguna's general dry glaze mixing instructions in https://4e1a0199-e3cb-4bc6-9d1a-f62c39960aec.filesusr.com/ugd/e5330f_6bae0b4596374aa7960ca367393ac0db.pdf Where it says Approximately 8 to 11 ounces of water per pound of dry glaze will be needed, but the amount needed varies per glaze. ... For specific recommendations on how much water to add call 1-800-4Laguna I make that a ballpark of 9.5 oz water to 16 oz dry-glaze. So there are 100gm of dry-glaze in 100*(16+9.5)/16 gm of made-up glaze (~160gm). Can someone do a sanity check on the figures.
  9. Not competing with Neil's excellent suggestion, but an example using wire. The Nichrome Wire Solution: An Alternative to Raku Tongs Makes Raku Firing Large or Lidded Pots Easy https://tinyurl.com/539u7ky2
  10. Which ball-clay are you using, and do you have a choice? Organic Matter in Clays: Detailed Overview https://digitalfire.com/article/organic+matter+in+clays%3A+detailed+overview Note: According to F. Q. Al Khalissi e W. E: Worral (Trans. Brit. Ceram. Soc., 8,1982,pag.145) organic substances can be completely removed by treating the ground clay with water oxygenated at 30% vol. and heated for several hours at approx. 80 C. https://www.potclays.co.uk/ball-clay-twva?search=ball clay PS Have you checked for black-core? PPS LOI looks like a simple way of checking the level of organics in your ball-clay. PPPS Would pre-burnout of some of the ball-clay as a power help? A thought inspired by this comment in https://digitalfire.com/material/ball+clay Ball clay typically does not comprise more than 30% of a body recipe so its opportunity to burn away is sufficient.
  11. At low concentrations, gaseous carbon dioxide appears to have little toxicological effect. At higher concentrations it leads to an increased respiratory rate, tachycardia, cardiac arrhythmias and impaired consciousness. Concentrations >10% may cause convulsions, coma and death. A few of the sites I used to visit had equipment rooms with CO2 flooding in case of fire, and took the dangers quite seriously. I think somebody had died in an incident at another company.
  12. Apparently yes https://www.mondaes.com/products/wonderwhitedryclaycone06 I cannot see a part number associated with it by this supplier. https://www.georgies.com/pdfs/catalog/Page PDFs/01-9.pdf But part number is CCD547
  13. Can you take a much higher resolution picture of a few of the spots? The fine-detail might give somebody a clue about their development. PS There seem to be a few low-density regions in the spotting, does that say anything about glaze/spot application (or movement)?
  14. That's a bit clearer, but I'm failing to see how the main pour could distort the shapes or lead to bleeding between the two slips. Are you certain that some of the slip in the main pour isn't infiltrating between the shapes and the mould? Perhaps you could scratch an unsuccessful casting to examine the 3D structure. If that's the case you might find this of interest Inlaid Slip Casting https://tinyurl.com/2j6ubnue
  15. Are you trying to do something like this? Or like one of these? Slip Casting Molds: What are they, why use them and how to achieve different aesthetics. https://www.jennyrijke.com/blog/slip casting molds different aesthetics-
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