PeterH

Video of the polisher in action Possibly examples of the OP's work at: https://toaf.ca/gallery/jason-schiedel

Related thread here

If you are buying a meter is it worth getting one with a clamp ammeter? They look quite cheap and presumably can be used to measure in-situ per-element current.

PS It seems that a lot more products now have magic in the title. So an eBay search for something like magic cloth calligraphy is required.

Pictures might help identify your problem. You seem to be saying that the casting partially detaches itself from the mould at some point. Two ways that this can happen are: 1) A vacuum develops in the mould as the slip is poured out, pulling part of the casting away from the mould. Which can happen if the neck of the mould is blocked by the slip at some point (preventing the free entry of air). In extreme cases this is accompanied by a glugging sound. Note that this can be caused either by poor pouring technique or unsuitable slip properties. 2) Excessive trimming before the cast is dry either physically dislodges the wall or removes support during drying. One thread on the topic:

+1 for LinR's suggestion. Article here https://ceramicartsnetwork.org/daily/article/Resist-Inlay-A-Simple-Decorating-Technique If you want to use a pen,you may find this thread of of interest.

Pure speculation. As pH meters are so cheap (while presumably still functional) might it be worthwhile monitoring the pH of "unstable" glazes with slightly soluble components. Hoping it gives an early clue about when magnesium additions are required. e.g. Digital pH Tester Pen Water Pool Hydroponics Drinking LCD Test Pocket Electric https://tinyurl.com/4pd8wn4m PS I've no idea what range of pH covers the flocculation process. The buffering effect of the clay could make is very small.

Who is your supplier, and have you looked for alternative suppliers? It would be a pity if your first order didn't look like your existing samples.

Certainly temperature has an effect. And I think that a small amount of clay will deflocculate faster than a larger amount would (as it needs fewer sodium ions to do so). Flambe magic (John Britt's experience of crystal forming in glazes through thermal cycling) http://ceramicstoday.glazy.org/articles/flambe_magic.html Deflocculation https://cawstudiopotters.wordpress.com/deflocculation/

I wonder if the amount of clay in the glaze influences the number of sodium ions needed to change the pH by a given amount? If so the level of deflocculation will change faster the less clay there is about to "buffer" the pH -- as the rate of leaching of sodium ions from the nepheline syenite is presumably hardly influenced by the amount of clay about.

That's what I hope the experts will explain. I was just pointing out the use of a specific suspension agent for another glaze very high in nepheline syenite.

I'll leave it to the experts after mentioning this high nepheline syenite glaze previously posted, which uses a particular suspension agent. PS Glaze additives: https://clayworkssupplies.com/wp-content/uploads/2022/03/Glaze-Suspenders-and-Additives.pdf

Do you have a recipe (typical or "base" if you have many variants). What are the soluble ingredients? Do you dip or brush, and what volume of glaze are we talking about. Your wording suggests that all the glaze solidifies, but you title says hard-panning which I associate with a thinnish hard layer at the bottom of a liquid.

Certainly ingenious, and devised years before digital controllers were a possibility.

It produces a pulse-width modulated power supply. https://techcircuit.org/how-an-infinite-switch-works/

A manual for a popular kiln-sitter, to give you a flavour of maintenance issues. http://www.fireright.com/docs/kilnsitter/lt3andk.pdf

If it is necessary to convert the kiln to a normal 240V power supply. Am I right in thinking that it would be difficult to do this while retaining the 4-way switches. (This makes me really doubt that the kiln has already been modified for 240V operation.) While replacing each 4-way switch with an infinite switch looks pretty straightforward, and gives you a little more temperature control. I have a feeling that @Bill Kielb expanded on this idea in another thread, but I couldn't find it.

Are you sure that you are supplying the correct power to the kiln? PS It looks to me like the way the switches are wired means that you may be able to apply full power without the neutral wire, but low and medium definitely require the neutral wire.

If you have it handy I would welcome a reference. Does your" hmm" indicate that you have a problem with the statement? PS I think that this statement is a reflection of the fact that phase diagrams are "funny" in the sense that they represent what happens given sufficient time to reach stability. The classic example is that of carbon, a part of the phase diagram is given in: https://opengeology.org/petrology/8-igneous-phase-diagrams-and-phase-equilibria/ Diamond is thermodynamically unstable at pressures less that 10s of kilo-bars. So at normal atmospheric pressure of 1 bar it apparently shouldn't exist! ... given sufficient time it will convert to graphite ... but it persists over geological timescales.

Don't some/many commercial "paper" clays use flax fibres, which I assume don't rot. My experience with paper clay was also long time ago. Non-paper fibres were available but IIRC the minimal order was both expensive and very bulky -- while cheap toilet paper was readily available everywhere. PS Another option to prevent rot, keep the paper clay dry. Also see the next post in that thread, which recommends copper carbonate. Which I believe is sometimes used as a disinfectant in in glazes.

Is this thread any help?

I don't think that firing within the manufacturer's guidelines guarantees that your form won't slump. Probably only an issue with forms outside the usually pottery shapes, as previously observed by Hulk. Think of a sheet of printer paper. Hold it by the short edge and it flops about. Tape the long edges together and it forms quite a strong cylinder. Compound curves are probably even better at resisting deformation. I suspect that during firing sheets of clay bend easily, unless the bending requires local stretching or compression of the sheet.

I imagine that the relatively small amount of plastic materials in many casting slip doesn't help. https://digitalfire.com/article/understanding+the+deflocculation+process+in+slip+casting First consider how casting body dry ingredient recipes differ from plastic bodies. Casting bodies do not need to be nearly as plastic as jiggering, throwing or pressing bodies since they do not require shaping. Plasticity is only needed to impart shrinkage so the piece can pull away from the mold and to give it adequate dry strength. Too much plasticity is actually bad because plastic materials are less permeable to the passage of water through them, the casting process is slower (casting speed is an important factor in the process) and ware can split in molds with undercuts.

This effect of variation near texture is know as glaze breaking. A not very helpful link to start you off

Making a "nice" egg shape might be a little tricky. If you don't have throwing skills you might try something like this... You might find refining the shape of the two cups on a "found" egg-shaped object before you join them gives more realistic results. Although I doubt that a chocolate Easter-egg would be strong enough. Maybe an Easter-egg shaped gift box? If you do have throwing skills there are several egg-throwing videos on YouTube, such as ... https://youtu.be/uXO8wlCVxLA https://youtu.be/iymjWjUVskI https://youtu.be/D8OyAgu-cjI