^6 oil spot MFA thesis - Electric Mid&Hi Fired Ceramics2024-03-28T09:55:40Zhttps://cone6pots.ning.com/forum/topics/6-oil-spot-mfa-thesis?commentId=2103784%3AComment%3A106788&feed=yes&xn_auth=noJust saw the newsletter. Thou…tag:cone6pots.ning.com,2017-06-12:2103784:Comment:1426732017-06-12T03:05:50.020ZJoseph Firebornhttps://cone6pots.ning.com/profile/JosephRosenblatt
<p>Just saw the newsletter. Thought I would share this.</p>
<p>I have been tinkering with an oil spot at cone 6. I have had some pretty good results. The thicker you put it on the bigger the spots. I haven't tried a really really thick application because I personally like the spots on the middle tile the best. So I quit pushing it further. The oil spot is just one I found online, although I guess the author abandoned it. I assume because their surface was not satisfactory.. I don't have any…</p>
<p>Just saw the newsletter. Thought I would share this.</p>
<p>I have been tinkering with an oil spot at cone 6. I have had some pretty good results. The thicker you put it on the bigger the spots. I haven't tried a really really thick application because I personally like the spots on the middle tile the best. So I quit pushing it further. The oil spot is just one I found online, although I guess the author abandoned it. I assume because their surface was not satisfactory.. I don't have any problem with surface as you can see from the pictures. Oilspots are really a beautiful thing. I plan on coating entire bowls in it and selling them soon. It looks so deep and galaxy like. </p>
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<p>Here is a bowl with a thin coat: <a rel="nofollow" href="http://community.ceramicartsdaily.org/uploads/gallery/album_1211/gallery_63346_1211_312380.jpg" target="_blank"><img src="http://community.ceramicartsdaily.org/uploads/gallery/album_1211/gallery_63346_1211_312380.jpg" class="align-full"/></a></p>
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<p>Recipe and source: <a href="https://www.flickr.com/photos/glazes/2500437618/" target="_blank">https://www.flickr.com/photos/glazes/2500437618/</a></p>
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<p>I have attached the tiles:</p>
<p>Left to right: Thin to thick.</p> This has been a very informat…tag:cone6pots.ning.com,2014-05-30:2103784:Comment:1069932014-05-30T12:16:51.848ZRodney Allen Roehttps://cone6pots.ning.com/profile/RodneyAllenRoe
<p>This has been a very informative discussion. If I remember correctly Vickery theorized in his masters thesis that the kiln actually reached cone 7. The CO2 release makes much more sense. I'm going to sub another base glaze with more "chalk" in it and see what happens.</p>
<p>This has been a very informative discussion. If I remember correctly Vickery theorized in his masters thesis that the kiln actually reached cone 7. The CO2 release makes much more sense. I'm going to sub another base glaze with more "chalk" in it and see what happens.</p> Thank you. That is very info…tag:cone6pots.ning.com,2014-05-30:2103784:Comment:1070722014-05-30T12:07:23.851ZLyn Rapleyhttps://cone6pots.ning.com/profile/LynRapley
<p>Thank you. That is very informative. I'm going to play . . .</p>
<p>Thank you. That is very informative. I'm going to play . . .</p> The oil spot glaze requires s…tag:cone6pots.ning.com,2014-05-28:2103784:Comment:1069862014-05-28T23:32:13.694ZNorm Stuarthttps://cone6pots.ning.com/profile/NormStuart
<p>The oil spot glaze requires something which will off-gas while the glazes are molten. As an example, Laguna Clay's Gerstley Borate has a LOI of 29.5% - about 30% of the weight of the Gerstley Borate becomes lost as gas.</p>
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<p>The gas created by Jon Britt's Cone 6 base iron glaze is Calcium Carbonate (whiting) with 43.9% LOI and Kaolin with 13.2%. <strong>Calcium Carbonate calcines (releases the carbon dioxide gas) above 848 C which is roughly Cone 013</strong>. </p>
<p>If you…</p>
<p>The oil spot glaze requires something which will off-gas while the glazes are molten. As an example, Laguna Clay's Gerstley Borate has a LOI of 29.5% - about 30% of the weight of the Gerstley Borate becomes lost as gas.</p>
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<p>The gas created by Jon Britt's Cone 6 base iron glaze is Calcium Carbonate (whiting) with 43.9% LOI and Kaolin with 13.2%. <strong>Calcium Carbonate calcines (releases the carbon dioxide gas) above 848 C which is roughly Cone 013</strong>. </p>
<p>If you create a top coat oil spot glaze which is not liquid close to this temperature, the lost gas will not create any mixing of the two glazes. <strong>Ferro Frit 3134 melts around Cone 015 so, as Alisa Clausen has found, Ferro Frit 3134 makes a good ingredient for an Oil Spot covering glaze</strong>. The frit in the top coat will be molten at the time the calcium carbonate gasses-off its carbon dioxide.</p>
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<p>One of the captions in Jon Britt's article is the following:</p>
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<p><em>This test tile shows the bubbling of an immature oil spot glaze. <strong>As CO2 bubbles rise through the glaze, they deposit iron on the surface after they seal over</strong>.</em></p>
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<p>So clearly the mixing reaction in that particular "oil spot" glaze is the off-gassing of carbon dioxide from a carbonate glaze ingredient, calcium carbonate, rather than the loss of oxygen from red iron oxide at Cone 7 and above.</p>
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<p>So use Black Iron Oxide if you want a black colored Oil spot, and use Red Iron Oxide if you want a red colored Oil spot.</p>
<p><br/> <br/> <cite>Lyn Rapley said:</cite></p>
<blockquote cite="http://cone6pots.ning.com/forum/topics/6-oil-spot-mfa-thesis?commentId=2103784%3AComment%3A107050&xg_source=msg_com_forum#2103784Comment107050"><div><p>What happens if you put some RIO and some BIO in the glaze, Norm. Would that give you the reducing and fluid portion of the glaze from the BIO and the crystalizing portion from the RIO? </p>
<p>I'm not knowledgeable about glaze formulation, I'm just working on what I've read about what to use different chemicals for in cone 6 glazes.</p>
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</blockquote> Reduction of red iron oxide t…tag:cone6pots.ning.com,2014-05-28:2103784:Comment:1070572014-05-28T19:47:32.724ZNorm Stuarthttps://cone6pots.ning.com/profile/NormStuart
<p>Reduction of red iron oxide to black iron oxide occurs at oxidation temperatures reached at Cone 7 and above - 2,250 F according to Jon Britt - well above Cone 6 firings.</p>
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<p>This is the reason Cone 6 red iron oxide glazes look best when using nearly 100% pure synthetically produced red iron oxide - because the red iron oxide you mix into the glaze is exactly the same red iron oxide your end up with on display in the fired glaze.</p>
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<p>The mixing mechanism in Cone 6 "oil…</p>
<p>Reduction of red iron oxide to black iron oxide occurs at oxidation temperatures reached at Cone 7 and above - 2,250 F according to Jon Britt - well above Cone 6 firings.</p>
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<p>This is the reason Cone 6 red iron oxide glazes look best when using nearly 100% pure synthetically produced red iron oxide - because the red iron oxide you mix into the glaze is exactly the same red iron oxide your end up with on display in the fired glaze.</p>
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<p>The mixing mechanism in Cone 6 "oil spot glazes" is something other than what Jon Britt postulates for cone 9/10 oil spot glazes - since Jon Britt agrees red iron oxide doesn't reduce at Cone 5/6.</p>
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<p>Perhaps Jon Britt meant for his Cone 6 Oil Spot glaze recipe to be fired in reduction in a non-electric kiln.</p>
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<p><br/> <br/> <cite>Jeff Poulter said:</cite></p>
<blockquote cite="http://cone6pots.ning.com/forum/topics/6-oil-spot-mfa-thesis?commentId=2103784%3AComment%3A107052&xg_source=activity#2103784Comment107052"><div><p>The auto-reduction that happens in an oil-spot glaze is a temperature related event. When the glaze hits that temp, the RIO auto-reduces and bubbles up to the surface dragging some shiny iridescence up with it. I'd have to look up exactly what that temp is. It's in several articles.....jhp</p>
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</blockquote> The auto-reduction that happe…tag:cone6pots.ning.com,2014-05-28:2103784:Comment:1070522014-05-28T18:15:57.178ZJeff Poulterhttps://cone6pots.ning.com/profile/JeffPoulter
<p>The auto-reduction that happens in an oil-spot glaze is a temperature related event. When the glaze hits that temp, the RIO auto-reduces and bubbles up to the surface dragging some shiny iridescence up with it. I'd have to look up exactly what that temp is. It's in several articles.....jhp</p>
<p>The auto-reduction that happens in an oil-spot glaze is a temperature related event. When the glaze hits that temp, the RIO auto-reduces and bubbles up to the surface dragging some shiny iridescence up with it. I'd have to look up exactly what that temp is. It's in several articles.....jhp</p> What happens if you put some…tag:cone6pots.ning.com,2014-05-28:2103784:Comment:1070502014-05-28T18:04:59.595ZLyn Rapleyhttps://cone6pots.ning.com/profile/LynRapley
<p>What happens if you put some RIO and some BIO in the glaze, Norm. Would that give you the reducing and fluid portion of the glaze from the BIO and the crystalizing portion from the RIO? </p>
<p>I'm not knowledgeable about glaze formulation, I'm just working on what I've read about what to use different chemicals for in cone 6 glazes.</p>
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<p>What happens if you put some RIO and some BIO in the glaze, Norm. Would that give you the reducing and fluid portion of the glaze from the BIO and the crystalizing portion from the RIO? </p>
<p>I'm not knowledgeable about glaze formulation, I'm just working on what I've read about what to use different chemicals for in cone 6 glazes.</p>
<p></p> I obtained nearly identical "…tag:cone6pots.ning.com,2014-05-28:2103784:Comment:1068802014-05-28T17:15:31.673ZNorm Stuarthttps://cone6pots.ning.com/profile/NormStuart
<p>I obtained nearly identical "non-results" with the Cone 6 combination glazes recommended by Jon Britt. I've found almost any other high iron glaze, like Orange Street, used as a base coat works better.</p>
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<p>Bear in mind that red iron oxide <strong>does not</strong> reduce to black iron oxide at Cone 6 temperatures and below, so the Cone 9/10 "oil spot mechanism" of red iron oxide releasing oxygen bubbles from the base glaze suggested by Jon Britt <strong>will NOT work at Cone…</strong></p>
<p>I obtained nearly identical "non-results" with the Cone 6 combination glazes recommended by Jon Britt. I've found almost any other high iron glaze, like Orange Street, used as a base coat works better.</p>
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<p>Bear in mind that red iron oxide <strong>does not</strong> reduce to black iron oxide at Cone 6 temperatures and below, so the Cone 9/10 "oil spot mechanism" of red iron oxide releasing oxygen bubbles from the base glaze suggested by Jon Britt <strong>will NOT work at Cone 6</strong>.</p>
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<p>The mixing mechanism between the two types of glaze at Cone 6 has to be <strong>carbon dioxide gas being released from carbonates or thermal currents.</strong></p>
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<p>Alisa Clausen tried these Britt recipes and other recipes (substituting a Scandinavian boron frit 169 similar to Ferro 3134 for gerstley borate or any frit listed, and a local balanced feldspar similar to Custer Feldspar for all references to feldspar). Note the the hyper-links #1 and #2 adjoining some of her photos no longer work, but the linked recipes still exist on the page with her other oil spot photos.</p>
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<p>These are her results and non-results with this firing schedule below. </p>
<p><a rel="nofollow" href="https://www.flickr.com/photos/glazes/sets/72157605126678933/" target="_blank">https://www.flickr.com/photos/glazes/sets/72157605126678933/</a></p>
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<p>Alisa Clausen Firing ramp with an electric controller is:<br/> 100c p/h to 600c (212f - 1112f)<br/> 150c p/h to 1140c (302f - 2084f)<br/> 80c p/h to 1220c (176f - 2228f)<br/> 15 min. soak<br/> cool down max. to 900c (1652f)<br/> Hold 30 minutes</p>
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<p>As proof that red iron oxide reduction is not the mechanism at Cone 6, <strong>I replaced the red iron oxide in Jon Britt's iron glaze with black iron oxide</strong>. As black iron oxide is a flux at Cone 010 and above, the base glaze is more fluid than the refractory red iron oxide version, so the top coat does a good deal of sliding about on the black iron lower glaze.</p>
<p>The top layer in this instance is one Alisa Clausen used with Praseodymium Yellow Stain.</p>
<p><a target="_self" href="http://storage.ning.com/topology/rest/1.0/file/get/3127169668?profile=original"><img width="721" class="align-full" src="http://storage.ning.com/topology/rest/1.0/file/get/3127169668?profile=RESIZE_1024x1024" width="721"/></a></p>
<p><br/> <br/> <cite>Rodney Allen Roe said:</cite></p>
<blockquote cite="http://cone6pots.ning.com/forum/topics/6-oil-spot-mfa-thesis?commentId=2103784%3AComment%3A106788&xg_source=activity#2103784Comment106788"><div><p>I just fired a load with small pots with the two glazes <a rel="nofollow" href="http://ceramicartsdaily.org/ceramic-glaze-recipes/glaze-chemistry-ceramic-glaze-recipes-2/oil-spot-and-hares-fur-glazes-demystifying-a-classic-ceramic-glaze/" target="_blank">John Brit</a>t listed in a CeramicArtsDaily piece;</p>
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<p>What I got by brushing 3-4 coats of each glaze was what looked like a white glaze on a clay body with manganese granules in it. I fired to cone 6 with a 30 minute hold. I'm not sure how to proceed. Longer hold? Thicker layers? Different glazes?<a target="_self" href="http://storage.ning.com/topology/rest/1.0/file/get/3127169346?profile=original"><img width="721" class="align-center" src="http://storage.ning.com/topology/rest/1.0/file/get/3127169346?profile=RESIZE_1024x1024" width="721"/></a></p>
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</blockquote> I just fired a load with smal…tag:cone6pots.ning.com,2014-05-28:2103784:Comment:1067882014-05-28T11:55:21.584ZRodney Allen Roehttps://cone6pots.ning.com/profile/RodneyAllenRoe
<p>I just fired a load with small pots with the two glazes <a href="http://ceramicartsdaily.org/ceramic-glaze-recipes/glaze-chemistry-ceramic-glaze-recipes-2/oil-spot-and-hares-fur-glazes-demystifying-a-classic-ceramic-glaze/" target="_blank">John Brit</a>t listed in a CeramicArtsDaily piece;</p>
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<p>What I got by brushing 3-4 coats of each glaze was what looked like a white glaze on a clay body with manganese granules in it. I fired to cone 6 with a 30 minute hold. I'm not sure how to…</p>
<p>I just fired a load with small pots with the two glazes <a href="http://ceramicartsdaily.org/ceramic-glaze-recipes/glaze-chemistry-ceramic-glaze-recipes-2/oil-spot-and-hares-fur-glazes-demystifying-a-classic-ceramic-glaze/" target="_blank">John Brit</a>t listed in a CeramicArtsDaily piece;</p>
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<p>What I got by brushing 3-4 coats of each glaze was what looked like a white glaze on a clay body with manganese granules in it. I fired to cone 6 with a 30 minute hold. I'm not sure how to proceed. Longer hold? Thicker layers? Different glazes?<a target="_self" href="http://storage.ning.com/topology/rest/1.0/file/get/3127169346?profile=original"><img width="721" class="align-center" src="http://storage.ning.com/topology/rest/1.0/file/get/3127169346?profile=RESIZE_1024x1024" width="721"/></a></p> I never could tell if folks m…tag:cone6pots.ning.com,2014-05-28:2103784:Comment:1067342014-05-28T00:08:21.675Zjuli longhttps://cone6pots.ning.com/profile/julilong
<p>I never could tell if folks meant "thick in the bucket" or "thick on the pot". </p>
<p>I never could tell if folks meant "thick in the bucket" or "thick on the pot". </p>