chad tikibilly Posted October 27, 2020 Report Share Posted October 27, 2020 I make tiki mugs and have a small kiln in my studio (genesis mini LT1120), and have been slip casting mugs, 2 questions (many thanks in advance) Ive been using low fire slip and firing at cone 06, can i then fire my bisque at cone 5 to glaze ? if thats possible can i then fire a second time back cone 05? thanks chad Link to comment Share on other sites More sharing options...
Min Posted October 27, 2020 Report Share Posted October 27, 2020 54 minutes ago, chad tikibilly said: Ive been using low fire slip and firing at cone 06, can i then fire my bisque at cone 5 to glaze ? Nope, if you are using lowfire slip do not fire it to cone 5. You will likely have a puddle of melted mess or bloated and warped pots in your kiln if you fire lowfire to cone 5. 54 minutes ago, chad tikibilly said: if thats possible can i then fire a second time back cone 05? You kind of lost me here, if you meant can they have 2 lowfire (^05) glaze firings then that would be a definite maybe. Would have to try some tests to see how the glazes react to a second firing. What cone does the both the slip and glaze directions recommend for glaze firing? Welcome to the forum! Link to comment Share on other sites More sharing options...
neilestrick Posted October 28, 2020 Report Share Posted October 28, 2020 We bisque everything at low fire temps (cone 08-04) regardless of glaze temp, and then glaze fire at the cone at which the clay (slip) matures. In that case of low fire slip, that's around cone 04/05. You can do multiple glaze firings, but each firing affects whatever was already fired on it. If you want to do cone 5 glaze and then another firing at cone 06, you'll need to get a clay/slip that matures at cone 5. Link to comment Share on other sites More sharing options...
Callie Beller Diesel Posted October 28, 2020 Report Share Posted October 28, 2020 If you wish to bisque, then glaze and then fire a third time for something like a decal or some other overglaze treatment, yes, you can fire to a lower temperature. How your clay body reacts to this will depend on its composition. Some clays will eventually start to bloat with repeated firings. Link to comment Share on other sites More sharing options...
sue91 Posted October 28, 2020 Report Share Posted October 28, 2020 Hi, I'm new to this and just wanted some advice on bisque and glaze firing. If I bisque to correct clay temperature, can I glaze fire to a higher temperature ? I've made a jug, bisque and glazed fired but it leaks water, any advice ? Thanks in advance, Sue Link to comment Share on other sites More sharing options...
chad tikibilly Posted October 28, 2020 Author Report Share Posted October 28, 2020 On 10/27/2020 at 3:50 PM, Min said: Nope, if you are using lowfire slip do not fire it to cone 5. You will likely have a puddle of melted mess or bloated and warped pots in your kiln if you fire lowfire to cone 5. You kind of lost me here, if you meant can they have 2 lowfire (^05) glaze firings then that would be a definite maybe. Would have to try some tests to see how the glazes react to a second firing. What cone does the both the slip and glaze directions recommend for glaze firing? Welcome to the forum! Awesome thanks so much for the help. I'm currently using standard low fire white slop 021320. chad Link to comment Share on other sites More sharing options...
chad tikibilly Posted October 28, 2020 Author Report Share Posted October 28, 2020 1 hour ago, sue91 said: Hi, I'm new to this and just wanted some advice on bisque and glaze firing. If I bisque to correct clay temperature, can I glaze fire to a higher temperature ? I've made a jug, bisque and glazed fired but it leaks water, any advice ? Thanks in advance, Sue im also fairly new and fire bisque at 06 and glaze at 05. After the glaze dries I always put use a coat of duncan pure brillance brush on to seal my mug. They make a glossy and mat finish. Also before glazing brush you item with water removing all dust particles, which when firing can cause holes or possible leaks in the glaze Link to comment Share on other sites More sharing options...
Hulk Posted October 28, 2020 Report Share Posted October 28, 2020 Hi Sue! Expect your clay to mature when fired to the specified cone. If underfired, the clay may be (will be) somewhat porous and weak - bisqued! If overfired, several "bad" things could happen, depending on the clay and how much overfired - the extreme being a puddle. How tight a clay is when ideally fired does vary; see "absorption" value published by clay supplier. Although a low absorption clay should hold water, still a good idea to glaze the inside, at least. Glaze makes the piece stronger, and provides a water proof surface that's cleanable. Is your jug glazed on the inside? If glazed, is the glaze unblemished - no crazing, pinholes, crawling, etc.? Link to comment Share on other sites More sharing options...
Sorcery Posted October 28, 2020 Report Share Posted October 28, 2020 19 hours ago, chad tikibilly said: at cone 5 to glaze ? Did you mean 05 here? 3 hours ago, sue91 said: any advice ? Don't fill it with water! Lol. Could be cracked, more info? Clay, temp, etc. Sorce Link to comment Share on other sites More sharing options...
Denice Posted October 28, 2020 Report Share Posted October 28, 2020 I have fired C04 red terracotta to C1 and used a C1 glaze on it, the clay was vitrified at this cone but the glazed still crazed. The clay would start to melt at C2, your best bet is to fire the cone the clay is made to fire at. My teacher in high school left a kiln on overnight accidently, when he opened it he found puddles where pots use to be. He ruined a couple of kiln shelves, the kiln survived. He somehow talked the school board into replacing it with a large gas kiln. Denice Link to comment Share on other sites More sharing options...
Chilly Posted October 30, 2020 Report Share Posted October 30, 2020 I hope you've read all the No, nope, don't do it comments. I did, just to see what happened. As others have said, you get a puddle, that is the height of the thickness of your original item and the width and length of .... probably half your kiln shelf. If you don't believe us, try it, but with a small item, and put it into a large bowl or saucer that is made of high-fire clay. (Also sometimes known as a cookie.) Sometimes the only way to believe is to try. Link to comment Share on other sites More sharing options...
neilestrick Posted October 31, 2020 Report Share Posted October 31, 2020 Many terra cotta bodies can go to cone 2 or 3. If they have grog they can often go as high as cone 4. Low fire white bodies, however, especially talc bodies, begin to melt at about cone 1, and will be a really nice puddle of green glass at cone 5/6. I have see a number of kilns in my career where the owner ran a firing to cone 6 instead of 06 and ruined the kiln, like throw it away and get a new one. The best case in those situations is where all the shelves are ruined. but if it'a a full load, usually it flows into the kiln walls and onto the floor. Ceramics would be a whole lot easier if we all worked at one temperature. Link to comment Share on other sites More sharing options...
Babs Posted October 31, 2020 Report Share Posted October 31, 2020 5 hours ago, neilestrick said: Many terra cotta bodies can go to cone 2 or 3. If they have grog they can often go as high as cone 4. Low fire white bodies, however, especially talc bodies, begin to melt at about cone 1, and will be a really nice puddle of green glass at cone 5/6. I have see a number of kilns in my career where the owner ran a firing to cone 6 instead of 06 and ruined the kiln, like throw it away and get a new one. The best case in those situations is where all the shelves are ruined. but if it'a a full load, usually it flows into the kiln walls and onto the floor. Ceramics would be a whole lot easier if we all worked at one temperature. Or read th relevant info and believed it:-/ Link to comment Share on other sites More sharing options...
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