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Curious--does "produced by" mean making from mold and firings, or what does that element of the 3-person collaborative entail?

Thank you all for the insight. And thank you @Min, I was very curious as to the nature of that test.

Amen to that!

In a nutshell to pass the ASTM for "Microwave Safe for Reheating" there is mention of "no metallic surfaces" but no threshold limit for porosity or absorption of the claybody. Ware must show no degradation after the test nor exceed specific temperatures after a set amount of time at full power. I would hazard a guess that those discoloured areas on the plate have let moisture into the body which resulted in the plate getting hot when your son removed it from the microwave. Agree with you, that is one well fitting glaze to stand up for catering use then your home use for 20 years.

I guess I really need to be sculpting some large relief pieces myself to glaze at some point. My galleries would eat these up if they were larger, but they also take a lot of time...

Post some pictures of the element connections and the inside of the control box so we can see the relays.

Hi everyone - this is one of the VERY few threads on the internet about Superfire kilns. Seeing that this thread is years old, I do hope someone stumbles upon it again to help a gal out! I purchased a 240V 50A Superfire kiln (D295) off of Facebook and used it well enough for about a year before the elements needed replacing. I contacted Euclids and they sent me elements for it. The connectors they sent were fairly large - turns out there was some unwanted metal contact. When I turned it on there was some drama and the kiln shut off. I just got crimp connectors to save some space in the box, and naturally I forgot to label the relays… I have an ohmmeter to measure resistance of the elements but I’m unsure what they’re supposed to be reading since I can’t find any manuals online. are there any electricians on here that may be able to help me with the math??

If that is indeed the same kiln, then at 7.5 cubic feet and 45 amps, it may very well get to cone 9, maybe 10. If it's in good condition and the price is right, it could be a good purchase.

FYI - Quite often once fire folks will do a single firing at bisque speeds. In effect a bisque first to burnout everything then continue on to glaze temp, usually for tested clay and glaze products that work well this way without excessive glaze defects. If their clay is known clean or tested with a glaze known to work without issue then not so much at the reduced speed but the tested speed. I would not ignore the time at temperature unless verified ok through prior testing.

Good question. ASTM article (formerly $48) https://www.astm.org/c1607-12r20.html Mr. Hansen's article Microwave Safe (digitalfire.com) A Forum thread on the subject: Microwave safe. - Clay and Glaze Chemistry - Ceramic Arts Daily Community The ASTM article may include a standard/industry definition, idk. This is where I am with it: "...not melt or otherwise lose form, not leach bad stuff, not get too hot to touch after one minute in the waver [microwave oven] ...anything that gets more than pleasantly warm (empty, clean) is not microwave safe...!" I still have microwave test clean dry wares on my "to do" list. I have an inexpensive infrared thermometer now...

Some ideas on the causes & avoidance of problems in: Microwave safe https://community.ceramicartsdaily.org/forum/23-clay-and-glaze-chemistry/ PS Pedantically in the USA: ... although I expect that -- like many stress tests -- this only implies safe at the point of test rather than lifelong safety. [Unless you re-test after representative "wear and tear" such as crazing and chips.]

Microwave safe. What does that mean? I’ve been puzzling over this a while, a few years, at least. Lately an event, which I’ll get to, pushed me into posting the question here. My understanding was that vitrified clay wouldn’t get particularly hot in the microwave, but there was some question when it came to high iron clay bodies. Experience in my kitchen over twenty years bears this out, the semi-vitreous pots could be counted on to get hot, the really porous earthenware could get dangerously hot while the food remained cold. High iron clays don’t seem to behave differently, but I remain open to the possibility they can. The other experience I’ve noted is that any dish fresh from the dishwasher, even cooled to room temperature, will get hot in the microwave. My assumption is adsorption (water that intimately sticks to the surface), not just absorption, plays a role. The event that gets me seriously wondering centers on a diner plate. My dad was in the catering business and when he retired I snagged a few restaurant dishes. They’ve been in service for over twenty years in my home, unbelievably perfect ceramic engineering. Plain white, no chips, cutlery marks, or cracks, despite regular use and abuse (They’re diner plates, I don’t treat them like handmade pottery!). They don’t get hot in the microwave. My son burned his finger pulling one out of the microwave the other day. That didn’t make sense. Tonight he tells me he observed the plate closely and saw a craze and discoloration, and that it looked like a glaze crack, not a clay crack. I’m proud as a dad, he nailed it, though I doubted until I saw for myself. That discoloration is at about 11:00 in the photo, poorly visible I’m afraid. There is another blotch around 2:15. So finally, after all these years, one failed. Time for destructive testing. I threw that plate in the microwave, one minute. At 50 seconds, I added another minute. At one minute and fifteen seconds it shattered cleanly into three pieces. What did I learn? These plates, tough as hell, never got hot in the microwave for twenty years, never chipped, are in fact made of porous clay. I put a drop of water on the newly bared ceramic and it soaked right in. This rocks my world a bit. I honestly didn’t imagine it was possible to fit a glaze that well to non vitreous ware or that non vitrified ceramic could be so tough. The ASTM has a standard and a test for “microwave safe,” I’m not shelling out sixty bucks to read it. I’m not sure my pots would even pass the prerequisites to perform the test. I figured “vitrified”, as in 0.5%, was a prerequisite. What does microwave safe mean?

It’s below the lowest temperature I would consider bisque fired. It’ll be fragile. More absorbent, glaze will go on thicker than you're maybe accustomed to. Some people glaze greenware, it works. This seems beside the point. I don’t even know that you’re planning to glaze your work. Put a piece underwater overnight to see if it’s ceramic yet, shouldn’t be able to scratch it with your fingernail. It doesn’t matter if you fire 6 hours, 10 hours, or 50 hours, the clay has to get hot enough to change. If your kiln fails at bisque, how are you going to do a glaze firing? I agree with @Bill Kielb, troubleshoot everything from the breaker to the kiln. Fix that before making any other plans. Get some cones if you don’t have any, don’t rely on the pyrometer alone. There are no ceramics without a kiln (or a very very hot fire). You are ok, by the way. Things will work out.

1353 is cone 017 ish. I assume you were trying to go to cone 04. I would suggest refine to 04, hopefully you are using cones. Bisque firing removes organics and chemically combined water so how much time and how much time at temperature is the important part. I would troubleshoot the kiln, fix it then re-bisque to desired cone.

I hope you can reassure me I am ok. My old kiln quit after 6 hours at 1353 degrees for bisque set for 10 hr firing. It’s a speckled brown stoneware clay. It’s now very pink. It does appear to be ceramic and some of the pieces ring when tapped. Should I refire and do I do a complete 10 hr firing or can I do like. Quick 4 or 7 hour. I have an old Gare kiln using. Ramp master 2 controller. It failed at the breaker which we think was old thanks for your help

Good find! They appear to be out of stock though. But now we know the measurements!

Seems there are many .

I just saw on IG. a Japanese potter opening a pottery kiln of this shape slbeit it was a ceramic fibre gas kiln so MAYBE some one made kilns of this shape at some point.

Just an FYI update for anyone following, heard back from Paragon, they did not make the kiln but confirmed their elements will fit just the same. I made an enquiry with another company that repairs kilns and supplies elements here in Aus and they thought that the importer brought them out of England. At this stage I still have no idea where its from but have been able to confirm it draws 35amp when running.

It doesn't matter.

I use 1/2 shelves in the bottom, sharing posts at the center positions. I have never had a downdraft blower before, and find that my glazes are brighter. That said, I wonder about the circulation using 1/2 shelves, better or doesn't matter? In the years before with the old kiln, shelf stilts almost never matched up vertically, and I probably broke all ot the rules at home concerning kiln loading, but got very tight loads with lots of pots. Had to take off top section ro reach the bottom and then put it back on to finish loading. Loved that old L&L, but baby sitting with a full load was rough on the sleep patterns! Now I load and forget, paying attention to the ap on the phone! best, Pres

I was a horder of materials in my mid carreer so I have all the tin I need back when I used a lot and it was cheap and buying 1 ton of Gerstley was dumb luck long ago and thats what is in my white liner which we use a lot of these days . Now days I never worry about price of materials if I need it I order it.

They are great shelves same as advancers in every way only cheaper

Something a little different just finished up in my studio this week! 'Smitten' medallion (small plaque) , sculpted by Rebecca Turner, produced in earthenware ceramic by Marge Para, and custom glazed by myself as a show donation for Clinky Mania Live 2024 in Titusville, FL this May. All work done in the kiln using underglazes, then satin clear, followed by some overglazes to punch up the colors in the cat. This ceramic medallion measures 3.5 by 5 inches and is going to public auction to benefit the show. Photo displayed is MUCH larger than the actual piece! I don't do many donation pieces anymore as I am just too busy but this is to help support a good friend's last year of hosting this show series for equine ceramics. With all the heavy storms up here we've had in these mountains the past week it's been hard to fire either of my kilns with so many power outages and all the lightning. But I finally got it done!