PeterH
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glaze test tiles (can I use both front and back side?)
PeterH replied to s6x's topic in Clay and Glaze Chemistry
I haven't seen that, and would be interested if you have a ref. But I have seen occasional references to needing to let the pot dry sufficiently between glazing one surface and the other. ... this seems to be more of an issue with dipped glazes than painted ones. -
PeterH reacted to a post in a topic: Reitz Green without Gerstley Borate?
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Min reacted to a post in a topic: Reitz Green without Gerstley Borate?
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High fire clear glaze over under glaze - cloudiness
PeterH replied to Hendrixl114's topic in Clay and Glaze Chemistry
No, Min suggested switching to a commercial glaze used in an Amaco underglaze colour chart. -
Hulk reacted to a post in a topic: Reitz Green without Gerstley Borate?
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Reitz Green without Gerstley Borate?
PeterH replied to davidh4976's topic in Clay and Glaze Chemistry
Any relevance? https://digitalfire.com/material/gerstley+borate ... at the bottom of the page, discussing substituting Gillespie Borate for Gerstley Borate ... Clearly, the Floating Blue itself is firing greener than usual. And the Gillespie Borate version is much bluer. You may be used to something in between these two. The green tones could likely be restored by a reduction in the cobalt and increase in the iron oxide. -
Kelly in AK reacted to a post in a topic: Extreme shivering off underglaze
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I was interested to find this Australian article https://sydneynorthshoreelectrician.com.au/electrical-service-panel-how-to-calculate-electrical-load-capacity/ ... which contains these sentences It is commonly recommended that the load never exceeds 80 per cent of the capacity of an electrical service panel. and The National Electric Code recommends that the overall capacity of the load does not exceed 80 per cent, ... Which suggest to me that there is no regulation demanding "over-rating" of breakers (at least in that region of Australia). But there are both informal and formal recommendations that this be done - apparently for both continuous and non-continuous loads.
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HenryBurlingame reacted to a post in a topic: Gas or Electric Kiln For Starting Out
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Gas or Electric Kiln For Starting Out
PeterH replied to HenryBurlingame's topic in Equipment Use and Repair
It would be nice if you started a thread on the topic in say 3-12 months indicating your successes and failures in this area. PS A less well-known technique to achieve reduction. Which I think I've only seen mentioned in a 1932 paper on copper reds. -
Re-reading Digitalfire the second paragraph seems relevant.. Glaze Shivering https://www.digitalfire.com/trouble/glaze+shivering Shivering is the opposite of glaze crazing, the fired glaze is under compression and wants to flake off the body, especially at edges. However the route cause is a mismatch in the thermal expansions of body and glaze, thus the process of resolving it is similar as for crazing. It it much less common because glazes tend to have a higher thermal expansion than bodies and because they can tolerate being under compression much better than being under tension. Of course, if a glaze is under compression on the inside of a vessel, the body will be under tension and this can cause failure of the piece. When the body-glaze interface is not well developed an overly compressed glaze will be able to release itself much more easily, especially on the edges of contours. This can be the case, not only with low fired ware, but where engobes or slips are being used under the glaze. If the engobe does not contain enough flux to firmly adhere it to the body and develop hardness, it will not be able to bond to the glaze well. PS Time for some rim-shaped test-tiles?
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PeterH reacted to a post in a topic: Extreme shivering off underglaze
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PeterH reacted to a post in a topic: Gas or Electric Kiln For Starting Out
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Hulk reacted to a post in a topic: Gas or Electric Kiln For Starting Out
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HenryBurlingame reacted to a post in a topic: Gas or Electric Kiln For Starting Out
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Gas or Electric Kiln For Starting Out
PeterH replied to HenryBurlingame's topic in Equipment Use and Repair
If you are leaning that way have you explored slow-cooling in an electric kiln? Which can have a dramatic effect on some glazes. PS Some eye candy. https://ceramicartsnetwork.org/daily/article/Super-Cool-Slow-Cooling-in-an-Electric-Kiln https://cone6pots.ning.com/forum/topics/slow-cooling https://ceramicartsnetwork.org/daily/article/Tips-for-Increasing-or-Decreasing-Crystallization-in-Glazes ... same glaze fired in a gas kiln: with the "natural" slow cooling of a gas kiln & with a "crash" cooling similar to that usually given by an electric kiln. https://digitalfire.com/schedule/c6dhsc https://digitalfire.com/picture/bestenazoh https://digitalfire.com/picture/3348 A discussion on iron reds in this thread http://ralpotterystudio.blogspot.com/2010/08/new-glaze-tests-710.html ... a fairly mixed bag, including Previous firings of this glaze at cone 6 or less without slow cooling produced dark browns. This is one that really requires slow cooling to get the red appearance, but proves you can get red reds at cone 6. -
Idle thoughts while are are waiting for details of the kiln. If it's a 120V 17A Paragon they seem thin on the ground, see P5 of ... https://eadn-wc04-7751283.nxedge.io/wp-content/uploads/IM5-A-and-B-Paragon-Inst-Man-Jan2017.pdf Possibly relevant. https://eadn-wc04-7751283.nxedge.io/wp-content/uploads/A-11-9B.pdf https://www.theceramicshop.com/product/9663/paragon-a-11-9b-element-120v/ What mains supply do you have, and is 240V available? (Series wired with a 240v infinite switch would halve the current.)
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PeterH reacted to a post in a topic: Glaze thinning over time?
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ChrisC reacted to a post in a topic: Kiln identification
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I calculate 240/17.3 + 240/(8.6+8.6) + 240/17.3 = 41.7 amps I'm not familiar with kilns, but the difference between 40 & 41.7 could well be related to the fact that the resistance of the elements rises as they get hotter. PS There are lots of mnemonic diagrams about if you need a reminder of the formulae. https://duckduckgo.com/?q=voltage+current+resistance+triangle&t=ftsa&iax=images&ia=images
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ChrisC reacted to a post in a topic: Kiln identification
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Purely as an example, you can find Paragon kiln diagrams at https://corp.paragonweb.com/support/kiln-wiring-diagrams/ There are three for the TNF233 (single/three phase and probably different controllers), showing differences in resistance and connectivity between elements. e.g. https://eadn-wc04-7751283.nxedge.io/wp-content/uploads/Wtnf233.pdf BTW what is your mains supply? https://en.wikipedia.org/wiki/Mains_electricity_by_country Nominal voltage is 230/400 V, in practice 240/415 V is more commonly used.
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LeeU reacted to a post in a topic: The Pottery of Sound
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A picture of one of Carlton's horns, and other peoples work (e.g. 4-headed drum, multi-chambered wind instruments, ...) clay musical instruments https://www.pinterest.com/baldaufa1/clay-musical-instruments/
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https://ceramicartsnetwork.org/ceramic-recipes/recipe/Malcom-Davis-Carbon-Trap-Shino-143805# If the glaze ingredients are (partially) soluble it can cause troubles. 1) Ingredients that dissolve in the water are likely to finish up absorbed in the clay body, rather than remaining at the surface and entering the glaze melt. Maybe your recipe expected the soda ash to do this, but not the Nepheline Syenite ??? Expert opinions welcomed. <<< 2) If the glaze slop is subject the thermal cycling partially soluble ingredients can cause strange effects.
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A nice idea, which triggered this thought. There may be some ideas on the use of gourd-size resonators in this book that could be implemented in ceramics. change location and currency for some local prices https://www.bookfinder.com/search/?full=on&ac=sl&st=sl&ref=bf_s2_a1_t1_1&qi=OAsKRPTKCBg9erQLq0pcohcePyM_1714219097_1:2689:6113 ... perhaps sometimes using mixed-media (e.g. the banjo-like instrument).
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Can you confirm that you are talking about Amoco Palladium Glaze PC-04? Which seems to give a mirror-like finish by local reduction of manganese. As Callie has said you might try the ways people try to preserve reduced raku glazes, including wax polishes. I don't know if palladium luster gives a mirror-like finish. However as I believe that palladium metal is now even more expensive than gold I doubt that it's option worth exploring.
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PeterH reacted to a post in a topic: Making my first slipcast mold - Advice appreciated
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Maggie Powell reacted to a post in a topic: Making my first slipcast mold - Advice appreciated
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PeterH reacted to a post in a topic: Terra sigillata deflocculation from local clay
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PeterH reacted to a post in a topic: PID small kiln
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@neilestrick Could you comment on a couple of points. - 1) The kiln is rated at a maximum temperature of 1,240°C/2,264°F. What is a sensible firing temperature to give reasonable element lifetimes? 2) Fire safety. The manual states: Please only put this kiln on a heat-resistant worktop such as a metal stand, stones or ceramic tiles. Please note that the worktop should be very stable and be able to hold up to 30 kg of weight in total, for your safety. A photo in this advert shows the use of short legs/bricks. https://www.amazon.co.uk/Top-Loaded-programmable-Pottery-Projects-Beginners/dp/B0BZ53RXKM I assume that anything like this should be on a very fireproof/heat-resistant surface. PS @Moza Where are you intending to place the kiln while firing?