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Hi there, Thank you for all the wonderful info this forum, it is truly great and a HUGE help to everybody. I am writing from Dominican Republic. Here we do not have stores for ceramic materials and equipment like in the US. A lot of things need to be imported paying high freight forwarding fees. I have fired electric before and gas raku. Here the electricity is NOT AT ALL reliable and VERY expensive and we have regular power outages, which makes firing electric a big problem. I know most folks her recommend the conversion to a downdraft, but I wanted to try it this way as the downdraft conversion will be an added expense, chimney, etc... I am in the process of preparing a refurbished electric kiln onto gas updraft propane. Propane is more affordable here. I have read MANY of the posts on here and online about conversions and I anticipate the challenges ahead. also, Olsen's the Kiln Book, Mel's 21stcentury firing, and looking for the Art Of Firing by Nils Lou (very difficult to get), and many many more info online. A profesional potter friend is selling me an electric kiln to covert to gas (below the layout and some pics). He also used refractory cement on the inside walls (shown in the pics). It will have a layer of INSBLOK-19 1.5'' thick after the brick for added insulation, and then the stainless steel jacket. I would like the system to have a pressure gauge so that I can include the pressure info in my firing log and be able to learn as I go and become more efficient with my firings. I am planning to have as my max temp cone 5-6 (stoneware). Did a lot of earthenware before (electric) but would like to experiment / learn stoneware. I will have this kiln located in my 5th floor rooftop terrace outside. At the moment there is no roof, so I will be covering the kiln when not in use with tarp and a pice of corrugated zinc roofing. . I also have a pyrometer (dual thermo) and thermocouple that I will be placing in the kiln interior, 2-2.5 inches in (not shown in the layout). I only have 1 thermocouple for the moment and will wait to see if I need a 2nd one if I get too much temp difference between top & bottom. I wanted to ask, what is the pressure gauge in psi that I need? 0-15 psi? 0-30 psi? and the location of the pressure gauge, what should it be? According to this post which I have found that is VERY popular online about conversion: http://www.sebastianmarkblog.com/2018/07/gas-kiln-conversion-downdraft.html He advises to have the pressure gauge at the regulator in the tanks and control the flow form there. But I remember that I liked (in my old Raku kiln) to control the flow of the burner in the valve located on the galvanized steel pipe. I would like to have my gauge after that MAIN VALVE, to be closer to the kiln and be able to notice any changes (big and small) in realtime, and not be 8 feet away where the tanks are going to be. I wanted to check with you. Any help would be greatly appreciated. I have never used a gauge before but feel it will be great for my learning curve. If you notice the layout, I have 2 valves before each of the burners and before the MAIN VALVE. I am thinking that since this will be my main kiln, I will be single firing, from green to glazed, that I may want to start of with ONE (1) burner in the beginning and then turn BOTH (2) of them on as I progress. I imagine that the 2 RED valves before the burners would be both completely open for the large duration of the firing and I would control the flow with the BLUE MAIN VALVE. Many thanks in advance for taking the time to read this and if you have info, even general that yo think will help me, it would be great. Sincerely, Gus PS: Thank you again for all the info here, I have gathered / saved lots of info theory. Now I will be putting all of that theory to practice. Hope to eventually build an oxygen probe using a car oxygen sensor, as I found some instructions online. Big shout out to: @neilestrick @Mark C. @Marcia Selsor @Bill Kielb Thank you for all your info, have seen your names a lot combing the forums and your advice has given me a sense of grounding when I finally do it.
Hi, I would like to share my Kiln built and ask for some insights as my experience with Kiln were all in studios where others were operating it and I did not follow the whole firing cycle. I believe it is important to start saying that I was not sure if I should post it here or at "Equipment Use and Repair", please let me know. I will try to convert the metric information to imperial, but i may fail, apologies in advance. I decided to make a small kiln from K28 bricks (1530C / 2800F), the bricks are 65mm(2 1/2"). The bricks lay inside a metal drum, with a thin layer of ceramic insulation blanket, in order to reduce the gap between brick and metal, and try to add a bit more insulation; It is a Dihedral (new word on my vocabulary, twelve-sided polygon), and ~300mm (11 1/2"?) height, and ~300mm (11 1/2"?) "diameter", resulting in ~20L or 0.7ft3 From commercial Kiln, I found that 20L takes 2300W, threfore using an Europe power plug (230V and 13Amps): I used Kanthal A1 wire (1mm, AWG 18) aiming for 23Ohms, ie. ~12.5m (41ft).; I coiled the element around a 6mm (1/4"?), resulting in a Surface load of 5.89W/cm2 (38W/in2) -> I know this is high, but I struggled to find a thicker wire, I will replace that in the future; The element above, also resulted in a coil pitch ("stretch factor") of 4x when using 3x layers of element inside the Kiln, again on the extreme side, it will be fixed with a thicker wire; I also built the controller myself, which I can share if people are curious. With the introduction out of the way, I did a test fire on the kiln yesterday, aiming for Cone 05 1/2 -> 1015C or 1839F, as a test, since my local ceramic shop only had this cone in stock and I would like to validate against the thermocouple, type K, readings. The Kiln had a bottom shelf, raised 1/2" from the floor; the self supporting cone was placed in the middle. The ambient temperature was -4C (25F) After 10hrs , it was late and the Kiln was really struggling to raise the temperature more than 870C (1600F), the temperature was going up, but Very Slowly as seen on the graph below. Therefore I concluded that it would take few more hour to reach the final temperature (if it was able to do so). The firing schedule, not very relevant I guess, was: 120C -> 110C/hr | 250F -> 120F/hr 538C -> 250C/hr | 1000F -> 400F/hr 120C -> 167C/hr | 1659F -> 300F/hr 1015C -> 60C/hr | 1839F -> 108F/hr Finally, my questions are: Does someone have a 2300W Kiln and can share some experiences with the firing Cycle? Do you see any absurd flaw that would justify the behavior? Some pictures:
Hello everyone, I've been pursuing the forums a while... Wanting to get your thoughts - I'm trying to make a low fire propane kiln loosely based on Ian Gregory's flat pack kiln design. (http://www.ian-gregory.co.uk/kilns.html#flatpack) In my infinite wisdom, I jumped head first and just started building... Now I'm a bit worried. Will this end up a smoldering pile of hot metal? I have no idea how much heat is going to get through to the iron shell. Forgive the photo, I've yet to attach the side piece to the top of the grill.
Hi Ceramic Arts Community. I have an opportunity to custom build a kiln, made by a start up company that, to date, has only made very small (20cmx20cmx25cm interior) kilns. The company is a one man operation. That said, he has been working as a kiln repair technician for many years and is the brother of a good friend of mine. I have concerns about the specifications of the kiln and figured maybe this community might have some advice: Interior dimension 40cm x 40cm x 40cm and exterior 65 cmx 65cm x 65cm. So that gives a wall thickness of only 12.5cm (just under 5"). The target temperature is 1240 celcius and it will be top loading on wheels. Power is 220v and wattage will be 6200 watts. The controller will be a novus n480d and the lining will be kiln brick on top and bottom and I believe 3 layers of 1400 degree celcius soft insulation. Powder coated metal exterior. Anyhow, the price is about 30% cheaper than an established brand but honestly, not sure if I want to be a guinea pig even if it makes me disloyal to a good friend by not supporting his brother's newish business. Sorry for the long post. Any positive or negative feedback about the kiln specs (are the walls insulated enough) ; or other experiences with "home made" kilns is appreciated. Thanks in advance.