PeterH

Old thread ...

Slightly larger/more-legible version of the wiring diagram at https://skutt.com/images/181-Wiring-Diagram.pdf

No comment on the "quality" of the glaze, just the numbers. Looks like a fairly direct conversion of Coleman No Craze White https://glazy.org/recipes/3331 Custer for G-200, kaolin for EPK and silica slightly changed ... with the addition of bentonite and zircopax. The original recipe added up to 970 rather than 1000, which might account for funny numbers. PS Glazy seems to have the same recipe listed under Coleman No Craze White (New Zealand Halloysite) https://glazy.org/recipes/3806 ... which claims to be Adjusted for New Zealand Halloysite.

Have you thought about adding table salt? (Quick clay is formed by leaching sodium from the original marine clay.) ... although I believe that potassium chloride is now used for quick-clay landslide mitigation https://tspace.library.utoronto.ca/bitstream/1807/124221/1/cgj-2021-0230.pdf

Looks an interesting topic. Quick clay https://en.wikipedia.org/wiki/Quick_clay ... high-sodium marine clay changes is characteristics after the sodium is leached out. Quick clay landslides: an online documentary about Rissa https://blogs.agu.org/landslideblog/2020/06/18/rissa-ngi-video/ ... showing stiff-ish "found" clay liquefying under pressure to a pourable consistency. After adding salt it it is stiff enough to hold a knife upright. Quick though: are you looking at the properties of the as-dug clay, or has the washing involved in the filtering removed even more sodium? PS If you can give us the location where you found the clay perhaps somebody can find it on a geological map.

>Yes, I'm buying in the powdered clay from Potclays, it's their 1145. I have been using way more sodium silicate (based on the recipe for casting slip from Potclays themselves), so I suspect earthenware might behave quite different to stoneware I'm a little confused. Looking at Potclay's site they seem to give a "starting point range" rather than an actual recipe. Can you confirm this is what you are trying to use? https://www.potclays.co.uk/clays-slips-grogs/clays-slips-grogs-powdered-clays/white-st-and-39;ware-powder https://www.potclays.co.uk/recipe-casting-slip-powdered-clay As you don't have a definitive recipe I assume that you are doing small-scale experiments until you work one out. I assume that you started by exploring the range of recipes in Potclays recipe-range. Perhaps by a some variation on "keep slowly adding deflocculant until you reach the sweet spot" (or more precisely until you've overshot it a bit, but can reconstruct the recipe at the sweet spot). A rather formal version of the process is given in Determining Dispersant Additions for Casting Slips https://static1.squarespace.com/static/527ac372e4b0d4e47bb0e554/t/527fd7f1e4b0c046bfa9b90d/1384110065234/Dispersant+Addition+Procedures.pdf My guestimate based on Brongniart's formula suggest that these slips would have a SG of about 1.75 to 1.78 (see PS). So if the slip at the sweet-spot had been acceptable it would probably have met your needs. How bad was it? If the slip at the sweet-spot wasn't acceptable it might be worthwhile asking Potclays how you should proceed, as it makes their advice look potentially suspect. >Yea they are saying to use 3.5g for every 1000g of dry material but I haven't found that to get anywhere near fluid enough and I am using double that at 7g for every 1000g of dry material. But it's Potclays recipe advice for their clay. If their advice has any validity surely this should be resulting in significant overflocculation. Either something is badly amiss or Potclays recipe is totally misconceived. BTW can you confirm that your sodium silicate is 120tw and your soda ash is fresh. PS I note that Potclays recommend 25kg clay in 10l of water. So I'll try to work out its SG. Based on http://www.potteryatoldtoolijooaschool.com/brongniarts_formula_made_easy.pdf SG of clay is 2.5 to 2.6 And making Brongniart's assumption that the solids don't dissolve, but simply occupy their volume in the final slip ... Weight of slip = weight-of-clay + weight-of-water = 25kg + 10kg = 35kg Volume of slip = volume of clay + volume-of-water ... between 10 + 25/2.6 and 10 + 25/2.5 litres = 19.6 to 20 So SG of Potclay's slip is weight/volume = 1.75 to 1.78

A thread with a few references An online book 21st Century Kilns, and a few articles http://www.clayartarchives.com/

https://www.bookfinder.com/ is a good source for harder-to-find books. When you get to the list of matching books I find the or view all matches combined option useful.

@neilestrick As this is for enamelling would there be any merit in a minimalist solution based on a pyrometer and an infinite switch? I vaguely remember pictures of old glass/enamel/jewellery kilns which appeared to have this sort of arrangement.

A hybrid technology: stainless steel ring with inlay (here polymer clay). Video using Fimo Soft (maybe not the best polymer for jewellery) One source for suitable stainless steel "inlay" rings https://www.amazon.co.uk/dp/B09N6XQ1LG/ref=twister_B091KYY4B1?_encoding=UTF8&psc=1 PS This may be relevant Best Polymer Clay for Earrings and Jewellery https://sarahmaker.com/best-polymer-clay-for-earrings-and-jewelry/

This thread may be of some help.

Sort of, but ... - The SG of water varies with temperature. - Dissolved solids will increase the SG (mainly thinking of hard water). Size of the effects on SG seem small enough to ignore "for government work" https://www.hillcrestplumbingandheating.com/b/hard-water-vs-soft-water-debate-finally-solved The Guidelines for Canadian Drinking Water Quality Hardness rank hard to soft by CaCO3 levels. Here are their guidelines: Soft Less than 60 mg/L Medium Hard 60 to 119 mg/L Hard 120 to 179 mg/L Very Hard 180 mg/L or greater

Can you confirm that you are using CMC, not the Ceradel label gum.

Few materials can provide the truly remarkable durability of a metal ring. So would it be an idea to produce a set of three, to provide a backup in the event of wear/accident.

What started me looking at how you carved/machined rings. https://www.etsy.com/hk-en/listing/815905438/set-of-almond-wood-resin-couple-rings En masse https://tinyurl.com/2p9y83sy

I stumbled across "ring" drills. Posting the info in case anybody is interested. video: https://youtu.be/8QWjEqZUa3g?t=155 adverts: https://tinyurl.com/5yev7etz https://tinyurl.com/2jd32fye

oops, don't know how to delete.

I've not heard about firing "craft" ceramics directly in a microwave, though I would be interested to hear about it. I have heard about mini-kilns that you can heat in a microwave, and hence fire things inside them. Goodness knows how you control the firing profile. They seem to be really tiny and <£100, sometimes <<£100. Things To Consider Before Buying A Microwave Kiln https://www.soulceramics.com/pages/microwave-kiln-things-to-consider As mentioned above, not all firing projects are suitable to be processed in a microwave kiln. Most ceramics, for example, require a much higher heat than a microwave kiln can generate. Generally, microwave kilns can reach a maximum temperature of around 900°C, which is most suited to glass and jewellery projects. ... that's about cone 010. Microwave Kilns: Great Tools for Testing Low-Fire Lusters, Enamels, and China Paints https://ceramicartsnetwork.org/daily/article/Microwave-Kilns-Great-Tools-for-Testing-Low-Fire-Lusters-Enamels-and-China-Paints While the kilns don't fire high enough to test higher temperature glazes or clay bodies, they can really help out if you are interested in low-fire decorative applications such as china paints, lusters, Egyptian paste, overglaze enamels and many commercial decals. In this post, Jessica Knapp tells you all about this alternate use for old microwaves! A microwave kiln is a container kiln consisting of a base and hood made for use in a household microwave oven. The kiln is made of a white insulating fiber and lined on the inside of the chamber with a black compound that absorbs the microwave radiation and heats up to 1650°F or approximately cone 010 (figure A). The heat from this compound is then transferred to the chamber and to the piece being fired. It takes between 5 to 10 minutes to reach peak temperature ranges depending on the size of the microwave kiln, the work being fired, and the microwave’s wattage. After the firing, the kiln needs to cool for at least 20 minutes before being opened. Are you certain you cannot find somebody to fire it for you in a normal kiln, perhaps one of those paint-a-plate shops. PS I certainly wouldn't use the microwave for heating food afterwards. Some people recommend buying a 2nd-hand microwave for this. Some people claim to have some success (but cone 010?).

Considerably surpasses it in ingenuity.

I'm confused, the plate seems inconsistent, saying: 127/220 volts, single phase, 9 amps, 3300 watts. But 220v*9a = 1980w not 3300w. If there is a single infinite switch I guess it will need to be rated for at least 3300w/220v=15a rather than 9a -- unless you are sure that the plate wattage is incorrect.

Valuable experience. To emphasise the obvious: if @kawaiidumpling wanted to follow this approach they would need to make a casting-slip version of a commercial "sculptural" body. (As you cannot remove the deflocculant from a slip-casting body.)

Congratulations, some very ethereal results. Could you give a few more details of your process? I'm assuming it's something like: - Inkjet printing onto paper? - Sprinkling oxide/stain powder onto damped paper? - Press clay onto image? PS Vague memories at the back of my mind ( probably from reading about laser-printed transfer plates) suggest that pre-treating your digital image before printing it might change the nature of your final images. For example, digitally process your image to produce either a "halftone" B&W image or a low-resolution one. (Perhaps try 100dpi to see the effect, then maybe 300dpi in practice.) Print them at whatever resolution your printer has. You might get a more accurate greyscale.

You could also make/buy texture sheets/rollers to provide a low-relief background for your sculptures. e.g. https://www.etsy.com/uk/market/polymer_clay_texture_sheet

Posted the plate for the record

Still arguing for using the same body for mug and sculptures. If you want/need to attach hand-build sculptures, why not hand-build the mug. 101 on making a slab mug, with tips on rolling out the clay if you are unaccustomed to hand-building https://thepotterywheel.com/slab-built-mugs/ Personally I prefer to join round a tube of some sort, as in https://clairepalmerphotography.wordpress.com/2014/05/13/how-to-create-a-cylinder-vase-slab-building/