PeterH

People have used bisque moulds to slip cast in, although you may need to pick a bisque-firing temperature to maximise absorbancy. Note the contributions by @Tyler Miller and @Viking Potter in: Have you considered casting a plaster master in your silicone mould? If necessary immersing the mould in sand to minimise distortion. I assume/hope the silicone could be stretched to release the plaster master. PS I'll walk through the slip-casting process in order to make a few points about slip-casting. 1) Assemble mould The mould needs to be made of a very absorbent material (plaster is the almost universal choice). And you need enough plaster (or whatever) to absorb sufficient water from the slip to form the walls before you drain the mould. A slip-casting mould cannot have any undercuts, so the casting can be removed without damage. This form seems to require a 3-part mould: one for each "side" and another to handle the foot-ring. 2) Pour slip into mould. Casting slip needs to be suitably deflocculated and it contains a lot less water that watered down clay of the same viscosity. https://digitalfire.com/article/understanding+the+deflocculation+process+in+slip+casting Optimal casting requires that the slurry have minimal water content (e.g. 30% instead of 60%), good flow and draining properties and that it not settle out or gel too quickly. When the slurry is right the casting process works amazingly well. The slip is left for a while so that a thickened lay of semi-dry slip forms on the inside of the mould. The water removed from this layer has been absorbed by the mould. 3) Drain mould. The liquid slip is poured out of the mould, leaning the semi-dry layer layer on the mould walls. 4) Trim After waiting a while for the clay to firm-up a bit the casting can be trimmed. Small details of the mould are often designed to make this trimming fairly fool-proof. 5) Remove the mould. Wait until the casting is ready to remove from the mould. Too early release may result in slumping. Too late release can cause shrinking-on issues. ... then let the pot dry fully.

A slight quibble ... Digtalfire seems to think there can be issues when "late gassers overlap early melters". https://digitalfire.com/picture/huctibegac ... 1400F=760C So perhaps whiting can/does cause issues when used in combination with some early-melting ingredients, such as frit 3124.

I now realise my posting can be interpreted as a criticism of the advise in your earlier posting. This was certainly not my intention. I think adding another material with the same analysis as an existing one - simply because you are unaware of the existing entry - would be suboptimal practice. My current impression is that the OP wanted to use an existing entry for Frit 4064 but couldn't find it.

Hang on, something doesn't add up. Dick's advice is correct - if the glazy database doesn't already have an entry for the frit in question. However the database seems to have had an entry for Frit 4064 since 2018. https://glazy.org/materials/22651 Frit 4064 22651 Other Names Frit 4364, Frit 3531, Frit DA4064 Created 25 Sep 2018 Updated 5 years ago - are you sure the frit in question was 4064? - any chance of finger-trouble when you entered the name? - maybe try some of the alternate names? Confused, Peter

Looking for the x14 diagram on paragon's site I could only find one for the X14J, which seems to be for one segment only. https://eadn-wc04-7751283.nxedge.io/wp-content/uploads/WX14J.pdf @neilestrick The diagram gives a max temperature of 1650F (about cone 010?). Do you have any comments on expected element life versus firing temperature? It seems that the X14J was sold as a china painters kiln.

I hope that CMC has solved your problems, if not: - what cone/temperature do you bisque at - how dry is the glaze before you fire - what bodies have you tried (raku, e/w, s/w, hi-fire s/w, etc) - do you use real Gerstley B or a modern substitute

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

A memorable analogy

@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.

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.

Te previous thread is at

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.

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.

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/

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?

Deleted.

>>>> Please ignore, I thought I had deleted this FACTUALLY INCORRECT post <<<

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

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.

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.

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.

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

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

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.

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