PeterH

Yes it uses a target temperature rather than a target cone. But doesn't it also support program segments and ramp rates? https://thermaltechnologies.com.au/wp-content/uploads/2020/06/IPCO-Studio-3000-Manual_1_.pdf

When considering this it might be worth looking at the responses to this question on another thread.

Does the plate indicate a realistic firing temperature, or the maximum that can be reached with a full-spec power supply and new elements? I've seen a lot of recommendations that you need a cone 10 kiln to regularly fire at cone 6.

Nothing substantial to add, but this maybe of interest. The description "fine art" amaco kiln seems to relate to a series of kilns, can you find a more specific model number (might look like FA-<digits>). I'd hope there is a plate somewhere giving voltage, current, model number, etc. ... Can you find it and post a photograph? PS My impression is that these may not have been intended/marketed as general-purpose pottery kilns, for example the FA-44 is described as: http://www.americanceramics.com/html/amacofineartkilns.html The FA-44 is a well-insulated front-loading kiln with the capability to fire to Cone 03. Practical for small classrooms and studios, the FA-44 kiln is ideal for metal enameling, china painting, and glass decorating projects. An optional base is available for storing supplies and kiln furniture. ... @Callie Beller Diesel would you use a cone sitter for any of these applications? China painting typically relates to decorating already fired and glazed porcelain, hence: https://kilnfrog.com/collections/porcelain-china Porcelain or China Painting Kilns are typically smaller versions of Pottery kilns. They also typically fire at lower temperatures at 2000F. A kiln intended to function for pottery and ceramics is designed to fire to higher temperatures over 2200-2350F degrees, these high temperatures are necessary for firing the clay. I don't know if it's possible to find low-fire bodies and glazes which can be used at these temperature.

Oops, in that case Babs is right.

A very good idea. Which I tried to confirm by picking up the colours in graphics program, but they do seem different.

Perhaps a more eye-catching title title would be "Korean-speaking potter needs help".

Good idea Pres. May I suggest that @scottiebie considers trying to enlist the help of those Korean speakers on the forum. Perhaps by starting a new thread (with a title something like "Korean-language beginning-throwing videos and posters needed") explaining the problem. Maybe one of the more mainstream groups such as Studio Operations and Making Work would be more likely to catch their eye. A very superficial search suggests that English speakers might easily get overwhelmed by the number of Korean-language items on throwing Korean-style pottery (usually by experts).

I'm a great believer in "If it ain't broke, don't fix it". So I'm in total agreement that keeping to your tried and true process is the smart thing to do. To play devils-advocate. You are ensuring that there won't be problems during candling (by keeping below boiling point), and relying on your experience to know that any residual pore-water won't cause problems during the bisque. While somebody candling to 240F is ensuring that there won't be problems during the bisque (by removing virtually all the pore-water) , and relying on their experience to know that this won't cause problems during the candling. IMHO both are admirable strategies.

Most of it according to the first diagram I could find. Their ramp looks faster than yours, but I've no idea how "dry" the clay needs to be before starting this bisque firing. https://cawstudiopotters.wordpress.com/exp/kilns-firing/ Hamer & Hamer gives: The water of plasticity dries out from the clay in the atmosphere. The pore water is driven off by heat up to 120C (248F). The bound water remains as part of the clay compound (Al20O3,2SiO2,2H2O) until red heat, 600C (1112F). Elsewhere H&H say: the point at which the clay is theoretically bone dry is 120C (248F). I'm not sure what is meant by theoretically here. Is it the same thermodynamic style of argument that says diamond spontaneously decays into carbon (which it probably does, but it takes geological timescales to do so). I've no idea where (on the above diagram) all the water of plasticity has been expelled. Nor how much might be present before candling starts. PS Looking athttps://www.lakesidepottery.com/HTML Text/Tips/Clay drying and firing process.htm When the water has evaporated form between the clay particles, and all the remaining clay particles are in contact, drying shrinkage is complete. This is called the leather hard stage. The particles themselves are still damp, but their drying will not cause any additional shrinkage. So maybe the terminology is as simple as: Wet clay has water of plasticity, pore water & chemically combined water. Leather hard clay has only pore water & chemically combined water. Bone dry clay has only chemically combined water. Bisque clay has no water at all. ... which still leaves the practical matter of telling when an actual pot reaches these idealized states.

All embarrassingly good questions, I'll only answer the last one. Stuntman, singer and potter, he was somewhat of an exhibitionist and - at least at exhibitions - fired fast. His shopping-trolley kiln took about 10 mins for bisquit or raku, and 30 mins for stoneware. My vague memory was that his little-rocket reached cone 9 even faster. [Not certain if he used temperature or cones.]

In answer to your question. For water below it's local boiling point inward heat-flow causes the temperature of the water to increase, when the the local boiling point is reached some of it is converted to steam. The local boiling point is a function of the local pressure, which in turn will be influenced by any back-pressure generated as the steam tries to escape. AFAICT bara = absolute pressure in bars (atmospheric pressure is around 1 bar). My post was really just applauding @Kelly in AK for making the point that the thermocouple temperature doesn't indicate the current temperature of everything in the kiln, rather than offering a solution to the candling problem. And throwing in a little physics to indicate the complexity of the situation when evaporative cooling is involved. Hence just looking at the kiln's thermocouple probably doesn't give much insight into what is happening at the water-air interface within a damp clay body, and certainly not the temperature there. So - for example - wondering if the thermocouple can safely show a temperature just above boiling point (at atmospheric pressure) probably isn't a useful question. BTW I calculate that the 240F mentioned in the first post is the boiling point at ~2bar, so it cannot produce an back-pressure of more than about ~1bar. Hence 240F could well be safe for "normal" pots. ... figure generated via https://www.engineeringtoolbox.com/boiling-point-water-d_926.html?vA=2&units=B# ... I would certainly agree with treating "demanding/thick" and "high-invested-effort" items such as sculptures more conservatively. What I certainly don't understand is a point I heard Ian Gregory make. That he could fire (without candling) pots a few hours after he made them, but otherwise has to wait about a week to do so. A tentative guess is that a half-dry pot could have a dry (and thermally insulating) outer layer that lets the outer layer to become "too hot" before evaporative cooling kicks in, while a fully damp pot supports an evaporatively cooled interface moving gradually from the outer surface inwards. Anyway Ian Gregory's comment suggest that all damp pots are not equal, so we probably have to allow for the likely worst case in the load. In which case for normal pots perhaps a temperature picked to be incapable of generating "high" back-pressure might be a starting point, and a time derived from experience. Which is pretty well where we started. PS Has anybody done IR temperature measurements on pots while they are candling?

This background reading explains how the various types of electric motor can run "backwards" if mis-wired or a replacement wasn't a "drop-in". How to Reverse Your Electric Motor https://www.hecoinc.com/blog/why-is-my-motor-running-in-the-wrong-direction

Yes indeed. While it takes 100 cal/gm to heat water from freezing point to boiling point it takes another 541 cal/gm to turn it into steam. In domestic terms you put an uncovered stew in the oven at 180C and it fairly rapidly reaches boiling point, but then quietly sits there evaporating for several hours at 100C. The downside of course is that water expands by a factor of 1600 when it turns to steam, which needs to escape. Don't know the figures for chemically combined water. Latent Heat and Freezing and Boiling Points https://www.e-education.psu.edu/earth111/node/841 PS Loosely related The Art, Science, and Allure of Spain’s Water-Cooling Jugs https://www.atlasobscura.com/articles/botijo-jug But behind its apparent simplicity, the details of the botijo’s cooling system are incredibly complex. In the 1990s, two Spanish scientists developed a mathematical model to explain the details. They placed botijos in an oven and measured the water evaporation rate and the temperature drop over time. In the end, they came up with two lengthy and complicated differential equations to explain the mechanism. An ancient method of cooling water explained by mass and heat transfer http://quim.iqi.etsii.upm.es/botijo.pdf ... they placed a botijo full of water at 27.5C in an oven at 39C (simulating a hot day), seven hours later the water was at 24C. ... and you certainly don't want to follow the maths, but I don't expect that for candling pots is any simpler.

I'm not an Instagram user, but this might be worth looking at https://www.instagram.com/explore/tags/glazesharing/

Joanna Oliver uses it see https://tinyurl.com/mr23nadx You might try asking her, contact link at top RHS of https://www.joannaoliverceramics.com/blank-mpvle She sounds like she might be willing to share recipes:

Could you share the picture with us?

Although never say never ... https://www.plumetismagazine.net/technique-poterie-tournage-corde/

I cannot remember where I first saw mention of this technique, but I suspect that it was in one of your postings a decade or so ago. This image part-way through the stop-motion video I linked confirms that the clay is not coiled. Also note the profile board defining the outer shape The clay looks (and is described) as rather softer in another reference https://deborahsilver.com/blog/tag/handmade-garden-pots/ It is much more efficient to press the sticky clay into the rope. The form keep the clay from succumbing to gravity. ... These pictures detail how the wet clay is pressed into the rope covered form. The texture you see here-the finger marks of the person making this pot. ... Once the wet clay is pressed into the ropes, the wheel turns, and the surface is smoothed.

While trying to re-find earlier references I came across this smaller-scale example: John Maude demonstrates 'Jarre a la Corde'. https://www.easybats.com/jarre-a-la-corde-fun-stuff.html The frame and central axle idea looks really promising for heavy/tall pots, and might also take pointy bottoms in its stride. ... John Maude might be a useful contact. A google for Jarre a la Corde throws up a lot of interesting hits, including videos. PS An earlier ref still seems to work. ... although sadly the reference http://www.terre-en-formes.com/en/savoir_faire.html no longer works. PPS An image search for Jarre a la Corde also turns up some interesting pictures, for example showing different frame constructions. The first to catch my eye was http://www.prometheas.fr/blog/rencontres/rencontre-avec-pierre-bruzzi-la-corde-sensible-du-potier.html

I assume that this graph shows the progress to 1080C (and the kiln just hangs from there, but this isn't shown) ... is it coincidental that this glitch happens at the end of one ramp and the start of another? If the kiln was simply running out of steam wouldn't the angle of the ramp gradually reduce -- unless there was a sudden change in the thermal situation (like the lid springing a little further open).

For what it's worth, a firing schedule by original 4-way switch positions and the resultant power to the elements.

Is the handle also cast, or are you joining dissimilar bodies? PS Should you contemplate changing your process you may find some relevant comments in this thread, which covers more than the title suggests.

My guess at the physics of the process... Sodium Silicate is not a release agent, it's a deflocculant. It lets you make a workable slip with less water. But it's not the more the better, there is a sweet spot (which your usual casting slip will/should-be close to). Basically the mold sucks water out of the slip causing it to cast. The casting get slower as - - the cast walls get thicker (more resistance to water flow) - the mold gets saturated with water (and stops sucking) The first required patience (and perhaps optimization of slip properties). The second requires -- - either a thick mold which can comfortably absorb all the water that needs to come out of the slip to complete the casting. - or exceptional patience to wait while water evaporates out of the saturated mold, which then can start sucking again. - in either case starting with a really dry mold can only help. That's because in that case the extra water may saturate the mold even when you are only casting thin walls.

MOP over a black glaze