Jump to content

PeterH

Members
  • Posts

    1,403
  • Joined

  • Last visited

Everything posted by PeterH

  1. Just for the record Ceramic Arts Daily publish "15 tried and true glaze recipes" for (at least) raku, cone 6 & cone 10. https://ceramicartsnetwork.org/docs/default-source/uploadedfiles/wp-content/uploads/2015/08/15rakuglazes.pdf https://ceramicartsnetwork.org/freebies/guide/15-tried-and-true-cone-6-glaze-recipes https://ceramicartsnetwork.org/freebies/guide/15-tried-and-true-cone-10-glaze-recipes
  2. @Chilly did you have any undercuts?... PS Comparing fondant moulding with press moulding (probably the the closest pottery equivalent) ... The fondant process: — uses a flexible non-absorbent mould — the fondant sets hard (without shrinking?) — the set fondant doesn't adhere strongly to the mould? — fondant sets strongly enough that peeling the flexible mould off undercuts doesn't damage them The press moulding process: — uses a rigid and absorbent mould — the clay shrinks and becomes harder as it dries — minimal drying time needed/required —— the mould absorbs water from the clay; so no air-drying needed and clay-mould adhesion is minimised —— if the clay dries too much it will shrink-on any texture in the mould — you cannot cleanly extract the (still fairly soft) casting if there are any undercuts. So I suspect that you could have issues with — air-drying the clay — getting the clay firm enough — clay shrinkage — clay-mould adhesion — the undercuts PS Using paper-clay would probably strengthen the clay and speed air drying to some extent.
  3. An relevance? https://www.lickinflames.com/obvara_june_2021.html Generally speaking, the hotter the pot going into the mixture, the darker it will be. Nearly glossy black pots are from the hotter side of the firing range and tan pots are usually from the cooler side of the range. Really hot pots held in the mixture longer will yield fewer patterns. Cooler pots held in the mixture longer will possibly not carbonize as they cool below the threshold where carbonizing can take place.
  4. Yes, but it may introduce more problems than it solves. To my untutored eye it looks like firing with a sitter would probably solve your slumping issues. ... but would introduce glazing issues. The classic bone china solution uses a supported high-fire bisque and an unsupported lower-fire glaze, which creates its own problems. Bone China https://digitalfire.com/glossary/bone+china The process is completely different than what a potter would do: Bisque fire, glaze, high fire. Bone china is bisque fired to high fire and then glazed at a very low temperature. Since the porcelain has zero porosity, getting a glaze to stick and dry on it is not easy, the process needed goes well beyond what a normal potter would be willing to do. PS Balancing slumping and decoration has a long history. Robert Tichane expressed his surprise when he finally realised that the ancient Chinese cup he regularly drank from had a guilded rim to disguise the lack of glaze on the rim (a result of firing the cup rim-down to minimise slumping). I'm having difficulty visualising your "handmade leather molds". I assume that they are semi-flexible press-moulds, but am unsure how you extract the bowl from the mould.
  5. What cone/temperature do you fire to? PS I'm a little confused about the small print in the kiln spec. Continuously working time on 1240 C (2264): 10 minutes ... and in the manual https://www.technicalsupermarket.com/(EN) RH-16L KILN INSTRUCTION MANUAL.pdf Using this kiln at temperatures higher than 1,240°C/2,264°F or for longer than 20 minutes at these temperatures may cause problems with heating element(s) and/or with the kiln’s metal body that are NOT under warranty.
  6. Sorry, came up with a complete blank under that name. BTW I believe that chick grit is finer than chicken grit, for example: https://www.legbarsofbroadway.co.uk/grit-soluble-insoluble/
  7. Pure speculation ... If you continue having problems -- I wonder if the t-sig might be the issue, for example - by not adhering to the resist slip sufficiently - by not adhering to the body sufficiently (any signs of t-sig on the AWOL slip?) Obviously it works well for the Riggs, as can be seen in Terra Sigillata 101: How to Make, Apply, and Troubleshoot Terra Sig https://ceramicartsnetwork.org/daily/article/Terra-Sigillata-101-How-to-Make-Apply-and-Troubleshoot-Terra-Sig Naked Raku Orb by Charles and Linda Riggs, 2003. 7 in. (18 cm) in width. Stoneware painted with white terra sigillata and polished with a soft cloth, bisque fired to cone 010, covered in resist slip and glaze. Sgraffito through glaze before raku firing to 1400ºF (760°C). ... but do any of the t-sig troubleshooting ideas in the article apply?
  8. >>>> Please ignore, I thought I had deleted this FACTUALLY INCORRECT post <<<
  9. On very little evidence this might be a grass-ash (rather than a wood-ash). South Okanagan Grasslands Protected Area https://bcparks.ca/south-okanagan-grasslands-protected-area/ The Richter Pass has long been a priority for conservation efforts in the Okanagan. The primary role of the South Okanagan Grasslands Protected Area is to protect the dry grasslands and open forests that represent one of the four most endangered ecosystems in Canada. Glazy has some lawn-ash analyses at https://glazy.org/materials/15037 The materials section at glazy might complement digitalfire's coverage https://glazy.org/materials?primitive=1 Digitalfire also has Those Unlabelled Bags and Buckets https://digitalfire.com/article/those+unlabelled+bags+and+buckets
  10. Yes. Of course you are going to have a seam in the middle of the handle which may leave some sort of casting mark in the handles which you will need to make-good. PS Interesting but of low relevance: a thread that started out with a question on cast handles and digressed big-time.
  11. I think that you will find this difficult. It's more usual to use some sort of clay "build-up" to keep the plaster under control, as in PS A handle is nice and thin so there is no difficulty using a solid clay build-up. For larger objects you may want to minimise the amount of clay used for the build-up. e.g. https://youtu.be/pXQgi6vW22I?t=698 To state the obvious: bits of plaster can explode in the kiln, so keep any clay used for mould-making well away from the clay you use for making pots.
  12. There is a half-way house you might consider. Using a digital meter on a disconnected kiln. Measuring the resistance between connectors 2 & 6 on the relays before and after your changes would have clearly indicated a wiring problem while the kiln was still open. Probably before you had started rewiring the second element pair. The measurement could also give and indication of when the elements need replacing. Ideally you would like to know the resistance of each element, but that would require breaking & remaking the connections.
  13. Can you confirm that: - the controller is "alive" - it behaved exactly as it did when starting previous firings - it isn't displaying an error message Did you hear any relay clicks? PS Diagrams at http://coneartkilnsshop.com/index.php/wiring-diagrams/ ... are you using 240v? http://coneartkilnsshop.com//wp-content/uploads/Wiring_Diagrams/pottery/BXGX_1822D_1240rev21Aug23.pdf http://coneartkilnsshop.com//wp-content/uploads/Wiring_Diagrams/pottery/BXGX_1822D_1208rev21Aug23.pdf
  14. A little more detail (and perhaps a picture) would help the experts decide what's the best option for you. Some suggestions in this thread
  15. What size sieve do you use? Several people - including Min - pre-sieve their wollastonite through an 80-mesh sieve. This thread discussed the use of additives to ease this process, and possibly reduce the size of the larger filtered particles.
  16. It was a very tentative suggestions and I would certainly wait to hear what the experts say. If the idea seems worth testing I would start (and probably end) with ensuring that the wollastonite is well sieved, preferably with one of the additives mentioned. Personally for serious test I would mix with the additive and slake overnight before and after sieving to allow time for any surface "interactions" to occur. Maybe try with a cup of glaze taken from your well-stirred bucket. But with your low density of defects you'll need to dip a lot of test-tiles to cover the area required! PS Glaze Pinholes, Pitting https://digitalfire.com/trouble/glaze+pinholes%2C+pittingI If pinholes are isolated and few in number it may be possible that a contaminant is getting into the glaze. Pour a sample through a fine screen to check. Do not underestimate the value of ball milling to improve fired glaze surface qualities, many a problem with pinholing and blistering has been solved this way. Many companies ball mill up to 12 hours for best results.
  17. I've been having vaguely similar thoughts about larger wollastonite particles. I'm not suggesting that wollastonite particles can out-gas, but could their presence influence the seeding and/or movement of bubbles?
  18. In case it's of interest- googling site:community.ceramicartsdaily.org fibre soda firing threw up some hits including ... which includes In the 90's I decided to do a couple of soda firings in my ancient, Geil, fiber kiln. It sprayed the interior with ITC 100 and after just a couple of firings the old fiber just wouldn't stay put with the ITC. If you're looking for light construction you might try using IFB's, and coating 5 sides of interior bricks with the ITC 100. ... which uses fibre as a short-lived sacrificial liner Elsewhere I found this thread ... which includes this post
  19. I think it very unlikely that an organic plant-based dye would survive the firing process. Some ideas on colourants in: A Pit Firing Color Palette https://ceramicartsnetwork.org/pottery-making-illustrated/pottery-making-illustrated-article/A-Pit-Firing-Color-Palette Ferric chloride requires the use of adequate safety precautions. Read the literature if you are going to try it. A starter might be http://jsbarts.blogspot.com/2015/10/use-of-ferric-chloride-safety.html Some ideas in this thread, perhaps this post is a good place to start
  20. Two googles that might be worth trying, and an example hit from both. site:glazy.org "standard 266" https://glazy.org/recipes/22329 Shows a base glaze with several different colourants. "standard 266" glaze selecting the "images" option https://www.flickr.com/photos/133519868@N03/32484512766 Finally .. Glazy has an Alfred Blue at https://glazy.org/recipes/217896 ... and the referenced "University of Maryland Glazes" article is on p32 of ... https://ceramicartsnetwork.org/docs/default-source/uploadedfiles/wp-content/uploads/sites/6/2015/06/ceramics-monthly-feb80-cei0280d.pdf
  21. Maybe loosely relevant. @ChenowethArts has previously posted on ocarinas, although hasn't visited here since Jan '22 ...his website seems to still be online http://www.paulchenoweth.com/ but dates seem to be '21 ... contact page (was?) https://www.paulchenoweth.com/?page_id=718
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.