PeterH

Simply posting a link to another thread isn't a question. The first link is to a quiz on kiln design terminology. The answers are in the first post in that thread! But the answers can also be deduced from the majority guesses given in the replies. The second link is to a survey request on "sustainability in your ceramics practice" that doesn't seem to have generated a significant number of replies (probably because it was far too open-ended). Hard to see what the question could be. This thread is about "dishwasher and microwave safe pottery".

It will look something like this

I doubt it, but am not in a position to know. However you would only be using it to seal the unglazed edge of the collar, which would presumably not be in contact with the soil. Minimising any opportunity to leach.

Copper in lead glazes gives a very characteristic deep green that was very popular when the use of lead glazes was common. Lots of it about in my youth in the `50s and early `60s, mainly in older buildings. Sadly there seems to be no lead-free equivalent, for technical reasons. 1) The colour is explained by "crystal field theory". See The Origins Of Color In Minerals http://www.minsocam.org/ammin/AM63/AM63_219.pdf 2) In hand-waving terms the glass structure adopted by the lead ions leaves spaces into which the copper ions fit which distort the energy levels of the copper's electron orbitals. This distortion results in a green colour. Pedantically orbital-hopping electrons remove quite a lot of reddish light from the incident white light, leaving a green colour. 3) I believe that only lead (and lots of it) creates the environment where this happens. There remain lots of green copper glazes. From Copper in various cone 6 base glazes (Free Online Glaze Class Pt. 8) https://tinyurl.com/mrxx2ycu Perhaps this area might be of interest. ... but hard to tell without seeing actual examples.

Gearbox oil-change mentioned in http://www.potters.org/subject46261.htm and http://www.potters.org/subject25713.htm

In case anyone wants to try them in searches: Ted Randall & Dr Brownell were involved http://ceramicsfieldguide.org/pdf/val-cushing-handouts/special-extras/Cushing-OutdoorClay.pdf

Perhaps relevant: Outdoor Weather Resistant Ceramics https://digitalfire.com/article/outdoor+weather+resistant+ceramics This is a common sealer available at a hardware store. I have dipped the terra cotta tile and it has dried. The surface of the dipped portion is smoother and has a slight sheen. That is the price paid for sealing the matrix against freeze-thaw spalling.

Again only loosely related to the topic. A post by Val Cushing on an Alfred University test to see if non-vitrified bodies are susceptible to freeze/thaw damage. It's based on the ratio on two tests of porosity. http://ceramicsfieldguide.org/pdf/val-cushing-handouts/special-extras/Cushing-OutdoorClay.pdf https://digitalfire.com/article/outdoor+weather+resistant+ceramicsAn old newsgroup posting on the subject. freeze-resistant ceramics--reply to vince http://www.potters.org/subject98627.htm https://digitalfire.com/article/outdoor+weather+resistant+ceramicsAre any similar tests done for architectural terracotta bodies? PS Oops should have looked at Digitalfire first Outdoor Weather Resistant Ceramics https://digitalfire.com/article/outdoor+weather+resistant+ceramics It is possible to perform a simple test based on the principle that a sample of fired ceramic boiled in water will absorb more moisture than one that is simply soaked. This is because for the former, the entire network is filled, for the latter only the pores. This test compares the cold soaking absorption or open porosity (C) of a clay with its boiled absorption or closed porosity (B) . The structural ceramic industry requires a C/B result of less than 0.78 (in products firing to more than 5% porosity) in order to pass CSA and ASTM specifications for outdoor use. If you are buying clay, your supplier should be able to tell you what the porosity will be at the temperature you plan to use it. If it is over 5% (as noted above) then you should be aware of the closed-over-open porosity also. If they sell the material for sculpture and know that customers are using it outside in freeze-thaw conditions, they should be able to tell you this figure.

Different cultures, different practices. It can be very confusing at times.

Can you give us a recipe for a typical glaze you use? To give us an idea of the sort of materials you use, and because the colour generated by metal oxides can depend heavily on the base glaze used (especially copper). From Copper in various cone 6 base glazes (Free Online Glaze Class Pt. 8) https://tinyurl.com/mrxx2ycu PS Still remember the spectacular dark green copper-in-lead-glaze tiles in public buildings in the '50s and '60s.

Perhaps of mild interest, a fully explored example of colour/porosity/shrinkage versus firing temperature. SHAB - Shrinkage/Absorption Test https://digitalfire.com/test/shab Note that the section "How do you decide what temperature to fire this terra cotta at?" is mainly concerned with glaze issues. PS Do you include Code stone among "heritage unglazed architectural terracotta"?

I found this an interesting suggestion on how to add bentonite to a wet glaze. It's based on slaking the bentonite before any agitation/mixing. How to Add Bentonite to a Wet Glaze https://suemcleodceramics.com/how-to-add-bentonite-to-a-wet-glaze/ The sprinkle-on-water, slake, stand, remove-excess-water method looks like a low-risk way to try out the idea; revert to plan-A if it's lumpy.

May be relevant Plaster table https://digitalfire.com/glossary/plaster+table PS As this plaster bat is proud of the table there are no access issues at the edges.

To illustrate the consensus. Best before&after red-to-gold pics I could find, in this case gold lustre on glass. https://glasswithapast.com/knowledgebase/gold-and-palladium-lusters-on-glass/ Excuse the large pictures, but the colours don't show up as well in small ones.

Do you have a more naturally lit photo of the glaze, the highlights on all three glazes are rather overpowering. Or perhaps you can share the name of the artist so we can see their work on the net.

You can find your kilns part number from the info on https://paragonweb.com/support/kiln-wiring-diagrams/ If you then enter the p/n into the pages search field it will give you its kiln wiring diagram. This should show you the "as new" resistances of your elements. PS If you post your p/n it will help the experts customise their answers.

First, excuse me if I'm trying teaching you how to suck eggs. The positions of things on the schematics is essentially arbitrary, all it guarantees to do is get the connections between the components right. Components can be, and are, shuffled around the schematic to hightlights connections, minimise white-space and fit the page. As a lesser priority components are sometimes labelled or positioned on the schematic to reflect their interconnectivity or geometric relationships. When I talked about the "top" and "lower" infinite switched it was based on my limited knowledge of the physical layout of the control panel, not their positions on the schematic. (Although they happen to be in those positions on the schematic.) On the other hand when I said "top element" I assumed that the label "top element" on the schematic related to its geometric position on the kiln. Looking at the schematic the labelling of the top/upper-middle/lower-middle/bottom elements reflects their geometric position in the kiln. Their positioning from to to bottom of the schematic is presumably aimed to make the schematic more intelligible. IMHO the positioning of the relay feeding the "top element" on the the schematic is to clarify the connections on the schematic, not to define the geometric position of that relay. Which is a long-winded way of saying I think you have already got the right schematic. (Just confirm that the connectivity of the relay feeding the top element conforms to that shown by the schematic.)

Sorry, I meant there was unlikely to be a major flux-based "chromatic influence" for Celedons towards the golden metallic effect the paper was seeking. In this project, a kind of glaze that resembles metal glaze with golden color, simple color and no obvious luster

Yes, I intended the picture as an example of the effects of an applied leaf, and a mulberry leaf in particular. I was suggesting that the paper I was discussing seemed to start by looking at the traditional leaf-based way of obtaining an image and then thought: hey what if you used leaf-ash (or its chemical equivalent) as a "local surface additive". And the paper expands on the idea (I thought overglaze was less of a mouthful than "local surface additive"). Thanks for the thoughtful contribution and very interesting reference on colouring mechanisms. PS I find it interesting that the paper applied to technique to Celedons. Which I suspect would be less likely to be "chromatically influenced" by things like local flux changes than Tenmokos.

Assuming that the OP has already checked that all the elements get hot (glow, burned test papers, etc) ... Most of the smarts seem to be in the automatically controlled ramp-up, would a manual firing of the empty kiln with the thumbwheel full-on provide any useful information? PS A full-on infinite switch may well be on all the time so perhaps there wouldn't even be any relay switching.

An interesting spin-off? I welcome others interpretation of this paper (pity it doesn't have a pictures) Research on the New Woodleaf Glaze in Celadon https://www.scitepress.org/Papers/2019/85615/85615.pdf The image on a good leaf bowl is notable both for its fidelity and its colour. https://www.yuyinghuang.com/shop/mulberry-leaf-tenmoku-teabowl This paper thinks of the leaf as a way of applying an over-glaze image to the pot. It starts by analysing the mulberry leaf ash as it is heated, and comes up with a glaze formula: Any thoughts on the colouring mechanism? And is it a property of the overglaze alone, or a reaction with the base-glaze? It then considers the use of this overglaze which it uses with a celedon base-glaze. Combine with celadon's mud glaze to make no less than 6 sets of test pieces, (I'm not sure if it is applied it as an overglaze, or mixed it with the celedon.) ... and then looks at the effect of firing temperature. Pity there is no pictures. PS It would be interesting to know the analysis of the ash of other leaves traditionally used for leaf bowls.

@STONEWARECAFE I haven't sat down with the diagram for your FTX28 UP with coloured pens to clarify the connections, but my initial impression is that: 1) The shaft of the lower infinite switch is shared by the thumbwheel and the motor. 2) The lower infinite switch directly controls both relays (one for the top element, the other for the rest). 3) The top infinite switch is used to control the speed of the motor, so it steadily ramps up the temperature by turning the shaft of the lower infinite switch. PS Kiln diagram for your FX28UP FTX28 OP still hasn't given their kiln number (or pix of label), but the details will be in the Kiln Diagrams section of https://www.cressmfg.com/resources/

222 page thesis TRANSFORMATION OF SIX LEAVES GLAZE TO CONTEMPORARY CERAMIC BASES ON THE TAOISM CHARACTERISTICS https://tinyurl.com/4a48pyky In the research process, 768 glaze recipes have been tried. A total of more than 600 kilns have been fired, and more than 20,000 pieces of products have been fired. In the early stages there were a high probability of failures. However, the rate of finished products finally increased from 2% to 80%

木の葉天目茶碗 (Konoha Tenmoku bowl) https://www.teaforum.org/viewtopic.php?t=1863 http://www.tokorozawaclub.com/HP/okachan/konohatenmokutyawan.htm Seems to be some how-to pages (scroll past the first tiny ones) Sample pix I now appreciate John Britt's comment about removing them with a magnet better.

No process info. Young Chinese girls revive, innovate 1,200-year-old porcelain leaf cup making techniques http://en.people.cn/n3/2021/0113/c90000-9808774.html