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Everything posted by Kabe

  1. The bottom bricks are sort of falling out the bottom and I think if they get a new kiln it will be a down draft but I'm sure they will save the good brick.
  2. We have replaced the UMV controller that is on the outside of the electrical panel and checked all the lugs where it plugs in. It is a fireeye and we have replaced that. In fact when the eye sees fire it drops to 400 volts, maybe it we hade four eyes on the kiln it would fire. The ring will stay lit for a short time then the flame failure light comes on, that was why we thought it was the fireeye. Like someone said it is not the solenoid because it will open to lite the ring burner, it just will not stay open. We have repositioned the eye so it could get a better view but it still will not stay lit. My son, who is a electrician, said that there is no way we can get that many volts off of a 110 circuit. I have no Idea why we get this false reading. We even tested it with two different meters to see if it was repeatable and it is. A co-worker of mine recommended the tongue test like how you do a 9 volt battery but I declined. We did call Alpine but they said they don't work on this old of kiln anymore, although they did direct use to the parts we are using. The kiln tech who worked on it also changed out the control box that is inside the kiln. We are baffled as to what is wrong. We ordered a valve with a thermocouple and we are going to bypass the photo-eye system and set it up like a water heater. The kiln the instructor used at college was set up that way. The valve may be here Monday. I do believe that whatever produces the 500 volt reading is the problem, but I do not have the training to chase it down. At this point the instructor has a complete semester of bisque students wares and about a week left to get them glazed and fired. Bummer for everyone involved. Ain't clay fun, Kabe Thank you again for the help. On the bright side the school may get a new kiln this summer. We need to nurse this one through for one more semester. This one was installed in 1987.
  3. I work at a collage that has a 1988 Alpine kiln, Natural draft, Model ND-16, and the ring burner will not stay lit, which sets off the flame failure sensor. we have replaced the photo sensor, and the UVM control box and the highfire /soak switch. All the relay look clean and with no visual sign of shorting out. The kiln has been looked at by a kiln tech, to no avail. Someone in Tenn. said that it works off of micro volts and if there is a break anywhere in the wiring system (talking about a microscopic crack in the plastic coating covering the wire, not the wire itself) that will allow a single electron to escape and that is one to many for the electrical system. The power light on the control panel fluctuates. That does not seem right to me. I cleaned the key operated, power switch, but it still fluctuate. Would installing a new power cord make a diff? when you test the currant on both sides of the wiring of the photo light where it hooks into the panel the meter bottoms out like there is 500 volt going through it. you get the same reading at the control box. Why? Where would it pick up another leg of power or is that something to do with the way the photo light sensor works? We are to the point to where we are going to bypass the system and install a baso valve with a thermocouple, so we can fire the kiln and give the students their wares. Any advise would be helpful. They hope to replace the kiln this summer. thank you. Ain't clay fun, Kabe
  4. Thank you for adding me to your friend list. I will check out your videos on how to market art. wow what a concept, selling art.

  5. Thank you for adding me to your friend list. I will check out your videos on how to market art. wow what a concept, selling art.

  6. Wow!!!! I'm in love!!! Thank you for sharing this.
  7. I don't remember making a cast from I fired tile, so I'm not to much help in that area. I know that there are some great discussions about plaster casting in the posts. You can buy mold release for plaster casts, I use Murphy Oil Soap and it works for what I do. I tryed vasaline once and it made the cast soft, also the plaster has to be able to absorb moisture and I think the Vasaline would hamper that. Maybe my oil soap does too never though about that part before. Potters Plaster is at least 5 headachs better than hobby grade molding plaster, It is not hard enough does not hold up. I don't know what you bought. If your carvings have under cuts you will not be able to get them loose from the cast no matter how much release you use. I don't know how deep your cuts are. That's the few things that I know. Try looking back through the old posts, there are some very talented and skilled artists out there. The next one reading this may have just the thing. Happy Firing
  8. Hi Marcia. A friend of mine said someone in one of his college classes made some tile and when they were fire the tile "cupped" I guess that would be the word. They were like upside down bowls. I thought about this abit last night and maybe that would be more like a situation where if the glaze was on a pot it might of shivered and if thetile warped the oppisite way and the edges all pulled up it would be like crazing. It would be interesting to manipulate a glaze both directions and apply the test glazes to thin tiles and observe the effects. happy firing
  9. I do tile work and seldom have warpage but I mix my own clay and use a lot of grog. Let me ask this as a question because I might be way off base here. Could it be that the glaze is to tight and instead of crazing you are getting shivering. Seeing that it is a flat tile and not a circular surface maybe the edges are pulled up by the difference in thermal expansion. I know that shivering can tear a pot apart. I have a glaze that will break a porcelain pot everytime I try it. I do not know what glazes you are using or if all your tiles warp or just certain ones. Maybe someone who is better informed could tell if this is possible. Happy firing
  10. Julia Gallaway has a website that has some cone 6 white claybody's on it. I have made up a small batch of one of them, but I haven't ran any tests on it. might take a look there. Happy firing
  11. I may be wrong , it's happened before, but I think this is a plaster cast limited edition because of the splatters and how the wire is fused in the cast. If it were fired I think the wire would have melted. If it is clay it would be hard to scratch, it if it is plaster it will scratch rather easily. Happy firing
  12. This is a long shot and probably not right. Is there anyway a vent for the kiln (If you have a vent) is pushing air instead of pulling it out. My Kiln is out in a garage so I don't need a vent so I am not sure how they are set up on an kiln. If is possible for it to be going backwards this could put dust into the air. Hope this isn't pure stupid. But it might be. oh well. Hope you find the solution. and Happy firing.
  13. You can throw a centered cone, like when you first center your clay. Make it tall enough and small enough to set your vessels onto and you can use that to trim you work. Cover it with Plastic food wrap so it does not stick to you green clay. You can take the plastic back off if you need to adjust the size to fit your bowl. There are probably better way to do it but that works for me. Happy firing Kabe We would hate to have you abducted by the Humane society for braining your dog. I think small vessels are great test tool. I have started to throw all my glaze mixing bowls, cups large enough to hold 100 gram of glaze and a mixer beater. Part of it is because it is fun to have all these home made test cups and secondly I can use them to test glaze combinations. Like double dip rims. I number my glazes and put the number of the combination on the bottom of the cup with a wet mixture of red Iron oxide and bentonite with a small brush. Say glaze 101/402 that way if I want to repeat it It is easy to find. Plus it is good practice at throwing things the same size..
  14. Diane has a strong point. It is a lot easier to adjust your chair than to raise and lower the wheel, no matter what height you end up at. Happy firing Kabe
  15. Kabe, While it seems to make intuitive sense, that will not work with the clay body to obtain a COE figure. You are getting the COE of the body if it was FULLY MELTED into a glass........ which is likely going to happen at about cone 20-30. The reason that you can calculate COEs for melted glasses is just that... it is assuming that they are fully melted glasses. In that case, the individual oxide's COEs can be calculated to give an overall COE by their individual contributions to that factor. However no one has of yet been able to model the development of a COE for a clay body, because it is a mixture of melted glassy components as well as crystalline components. The variables involved there are immense. It will be a major breakthrough if/when someone figure out how to predict this. At the moment the ONLY way to come up with a clay body's COE is by using actual measurements. This is usually done using a device called a dialatometer. The dialatometer heats up a prepared sample rod and measures the actual physical expansion. A technique I have my students do in the ceramic materials (glaze chemistry and related studies) is to do a series of GLAZE recipes with a run of steadily increasing COEs.... running from a very low one to a very high one. Than apply the glazes to the clay body in question. At one end of the spectrum the glaze will shiver badly on the body. At the other end of the spectrum it will craze badly. SOMEWHERE in the place in between.... you will find the glas that fits the body. Using this number you can then APPROXIMATE the COE of the given body. best, .........................john Thanks John For the information. I have put this question out there before. This will give me a way to find out. There seems to be so much information to absorb. I am in a process of setting up triaxial glaze trials. Making a set of tiles that can be pressed out so test results can be hung up, where people can get some use out of the tests. Most of them end up in a shoe box . I can run a 10 stage strip with a glaze that will show slivering at one end and crazing at the other. Thanks again I am in the procss of learning the glaze chemistry and terminolgy involved with the art. Challenging. Happy firing Kabe
  16. You could take a piece you were willing to break. Glaze it, fire it to cone 6 and put it through a vetrification test to see what the absortion rate is. Just a thought. Might be an interesting bit of information for everyone. Sort of educational. happy firing
  17. I do not know enough about all that takes place when a glaze fired or why a second firing would cause it to shiver. I would think that the glaze on the pot that was fired the second time was not the same chemical composition as what it was in the first firing. A bunch of the stuff was vaporized the first time. I'm not sure if that would effect the outcome or not. I have refired things before and had no ill effects but it was not for the same reason. For me I would be afraid it might do it again. But I've been wrong before. I bet someone out there knows the reason. Happy firing Kabe
  18. Congratulations. Happy firing, Kabe
  19. Seeing we are talking about shivering. I have a glaze that shivers on porcelain but not my stoneware. I am working on a change. I use Digital Fire Insight for calculations. I know the figure for Thermal Expansion for the glaze is higher than most of my other glazes. Looking for a way to improve fit, I entered the ingredients of my claybody, as a glaze recipe. This gives me a Thermal Expansion figure. The premise being; If mix my claybody with enough water and add color, it would fix my pot about perfect. Might be ugly, but it would fit. I have not tried it yet. I am more interested in the calculations at this point. I want to use it as a way to check fit, comparing the claybodies number to the thermal expansion number of a glaze. Ballpark figure to get me close. Question, Is thermal Expansion the same as Coeffient of expansion or are they two different animals? One problem I have with using my claybody as a glaze recipe is that it contains a lot of grog. Grog isn't recognised as a glaze material so is not entered into the calculations. I'm sure it would effect the expansion. I do not know if I can get the COE # for the porclain or not to compare it to my stoneware, plus I'm not sure if the figure I have for my stoneware is correct. If this makes sence to anyone out there, please give a holler. As far as your Pots go. I think the advise of starting over is sound. My shivered glazes are like razor blades. If the glaze looked all right after you refired it but later on down the road is still shivered and it went unnoticed, it might be hard for a customer to digest the splintered glass. Crazing can continue for along time after it is fired, I do not know about shivering I would think it could because there could still be tension. Bummer for sure!!! Happy firing, Kabe
  20. I may be wrong here and if so someone will correct me and I would be thankful for that. But my understanding of crazing is on how well the glaze fits the clay body. If you glaze your bisqueware and then fire it to it's maturing temp, your glaze and you clay body will all be fired to the correct temperature and it should not craze, That is, if the glaze fits the clay body. Crazing is created by the different rate of shrinkage between the glaze and the body it is covering. The glaze is stretched so tight that is sort of shatters on the surface. I bisque to 08 and fire to cone 6 or if it is in a gas kiln it fires to cone 10. I never thought it made to much of a difference to what temp I bisqued to, as long as I heated the clay to the point that I have driven off all the water that was chemically contained by the clay. It starts at about 350 C and should be done at 500C . ( Clay and Glazes for the Potter, Daniel Rhodes) My fear is when it over fires and then my bisqueware will not absorb the glaze. I think underfiring a bisque load by one cone would not create a crazing problem. I am not sure what you mean by outgassing unless you mean the gasses that are released as it is fired, to me this could create a blistering and pinholing problem problem but if you fire everything to what the glaze calls for and let it cool at the right speed it should be ok. Happy firing Kabe
  21. Hi I would say more because I can be pretty windy. so to save time you might inter the word "reclaim" in the search box and I know you will find some information there. Have a great day. Ain't clay fun! Kabe
  22. Hi there, I would also agree you don t want to go too thick here, not that I have ever worked that big either. I would suggest though that you line the press mold with some canvass bands two or three inches wide. So that you can lift the bowl out of the mold without having to flip it. These lifting spots are easliy mended and you wont have to lift such a heavy mold. I would love to see a photo of how the whole thing looks in action... T The bands are a good idea. It may be that after I have made the top mold then the bowl will be upside down when I first form it and then I can add the reinforcement spokes without having to move it at all. As far as pictures go, the last picture I posted came out huge. I am not sure why my computer didn't read my mind and make the right corrections. All the other pictures I have posted have been ok . I have been taking picture of the process and when my computer and I get on the same wave link and I will try to post some. It is a really big bowl! It is the biggest One I have ever tryed to make. thanks for the help. kabe.
  23. Thank you, I just have to have it soft enough to add the pieces to the underside. I think I will go thinner like you suggested. Most sinks and stools are only about 1/2 inch thick but they are slip cast where mine will be a press mold. I'm not sure how that would effect the thinkness issue. But that's how we learn. The making of a mold on top will stop the distortion I think.That way all the clay is contained and has nowhere to go. I made the first form as the underside of the bowl, afterwards I thought it might be better to have shaped the mold so it was the inside of the bowl. Then I can run my clay through my slab roller and lay it over the hump, instead of trying to drop it into the cavity. The wight of that much clay presents challenges. I found that I can roll it on a 3 inch plastic pipe like you do pie-dough on a rolling pin and it is some what managable. by pouring the upper cast, I will have a cast of both. I suppose I could even use the two halfs as a slip cast mold, with a little modification. I do not have very much experience with slip casting. I hope to add it to my skill level someday. It would be a handy way to add detail to a fireplace, say you wanted to have some repeating figure or the like. Happy firing Kabe
  24. Technical Question; I am making a 32 by 6 inch deep bowl for a friend of mine to use as a mold to melt glass into. It is for a church baptismal. I have already made the plaster mold for the clay and have shaped the clay into it. When I flipped it the wieght of the mold distorted the clay. ( 100+ lb of plaster and about 120 lbs of clay is a lot to flip) I remade to bowl,so now I can make another plaster cast to go over the top to hold everything in place when I flip the mold but I was wondering what anyones thought were on how thick I should go with the clay. All the work I have done so far is to get to where I can form the final bowl, I was going to go about 1 to 1 1/4 thick and reinforce the underside of the clay mold with clay spokes on the underside of the bowl. Really it will just be a big biscuit bowl. He will put a sheet of glass on top of it and melt if into the cavity. The clay will be fired to about 1800 (Biscuit) to start with and then I think he will fire the glass to around 1000 to slump it. I am not sure of the exact temp. The clay I am using is my heavily groged tile clay body. It matures at cone 6. It seldom warps. Cracking could be a problem when I first fire it and dry it. Hope not. I will let it dry and fire on a bed of grog. Question; how thick would you recommend the clay to be? I do not want to wait forever for it to dry and also do not want it to be so heavy that it takes a fork truck to move it. Happy firing Kabe
  25. Leaves are fun to press into clay and make a plaster cast of so they can be made into tile pieces. Just have to watch out for under cuts if you have a thick or bent stem. you can build the clay up around a stem to block the plaster from going under it. you can take interresting looking tree branches and press them half way into clay and make a cast. Then you can use the impression to make sprigs to use as a border around a tray or another tile piece. Have fun. odd shaped stickes with bark or knots can be a great texture tool. sort of like a hammer to beat on the side of a wet pot. ain't clay fun Kabe
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