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alligator alley

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Posts posted by alligator alley


  1. 1) If you have a wheel my advice is to make slabs on the wheel. It's very quick using soft clay to slab it out on a wheel. The slabbed product has better aligned particles that will resist warping much better than anything rolled with a rolling device of any kind.

     

    2) Make a plaster bisque of anything that's already glazed if you like it that much. My best slump or hump molds are made with bisque, but if you're not able or just have a shape you like plaster cement like hydrostone works pretty well. I dislike No. 1 Pottery Plaster as it's too soft for this type of mold.

     

    3) Use porous molds to allow quicker setting and more even drying. Uneven drying will cause warping as the outside dries the surface in contact can't dry. Then when the wetter surface later does dry it pulls on the already drier surface causing warping. You can't really combat this except to not do it in the first place.

     

    I thank you for the tips, making my own molds seems to be the best all around for me, again thanks


  2. 1) If you have a wheel my advice is to make slabs on the wheel. It's very quick using soft clay to slab it out on a wheel. The slabbed product has better aligned particles that will resist warping much better than anything rolled with a rolling device of any kind.

     

    2) Make a plaster bisque of anything that's already glazed if you like it that much. My best slump or hump molds are made with bisque, but if you're not able or just have a shape you like plaster cement like hydrostone works pretty well. I dislike No. 1 Pottery Plaster as it's too soft for this type of mold.

     

    3) Use porous molds to allow quicker setting and more even drying. Uneven drying will cause warping as the outside dries the surface in contact can't dry. Then when the wetter surface later does dry it pulls on the already drier surface causing warping. You can't really combat this except to not do it in the first place.


  3. Describe the warp. Is the foot humping up as they dry upside down? If so, the bottom is too thick, or too thick in the middle. I have also seen this problem if the bottom is too wet while trimming. Sometimes I'll trim it, then trim it again after it dries a bit more.

     

     

    I am picking the slab up as soon as I get finished with the slabbing, not letting the clay set_up a while to firm somewhat, just read that I should do this. Thanks fo any input


  4. It sounds like you are draping slabs over molds?

    Are the slabs made with rolling clay from 1 side only?

    Give us more info on how and what you are doing so we can help

    mark

     

     

    I am draping over molds, but I do roll on both sides and try to pay careful attention to rolling at different angles, but I do pick the clay up without the sticks, have never done that, something else new to learn, haha, that's probably where I'm creating the problem, since clay does have a memory; also I roll to about 1/4 to 1/2 thickness


  5. Some general considerations for slabs . . .Thanks for the help, I use a slabroller and turn the clay as I go, rotating, I then pick the clay up and turn it over, don't know why i started doing this. I have always just picked the clay up and place on mold ,which I do spray with Pam.I don't have feet at this time, attach before real leather. I roll out to about 1/4 inch

     

    If you are hand forming/rolling your slab, be sure to rotate the slab as you form it. Avoid stretching/rolling it in only one direction. If you are using a slab roller, roll the slab back and forth at least twice to get an even slab, if possible, rotate the slab 90 degrees so you stretch it in all directions. If you can't rotate it on the slab roller, take a rolling pin and roll it in opposite directions.

     

    You want to keep the slab flat at all times if you want to make flat-ware (plates, platters). I roll my slabs between two pieces of canvass. After rolling on the slab roller, I remove the top canvass and use a dry wall trowel/scraper to remove any texture from the canvass. Then, I place clean newsprint on top of the slab, put a ware board on top of the newsprint, fold the edges of the canvass over the back of the ware board and flip it. The canvass holds the slab flat against the ware board. Remove the bottom canvass and clean up the texture with the dry wall tool or rib. Then I carry the slab on the ware board over to the table where I work. Using a sandwich approach to flipping the slab helps prevent warping when the slab is drying. Clay has memory; if you bend it, it will want to go back to that memory/shape later on.

     

    A good way to compress a slab, once it is made, is to take the ware board with the slab, hold it at about waist high, and drop it flat on the floor. Noisy, yes, but rather effective.

     

    If you are using a non-porous item for the mold (i.e., glazed wares, plastic tray, glass platter, etc.), the clay slab will stick and, as it dries, warp. Dust the surfaces of your non-porous molds with corn starch, place some cheese cloth between the mold and clay, or spray with Pam. These will act to prevent the clay from sticking to the mold surface as it dries. Watch for any undercuts in your molds; another place where the clay can get hung up while drying and warp.

     

    I use a sandbag -- a half cup or so of sand on some plastic wrap, tied up, then placed in an old piece of table napkin or tee shirt that is also tied up -- to press my slabs into a mold. (Actually, you need two sand bags, one for white clay, one for brown/red.) The sandbag allows you to shape the slab without leaving fingerprints or marring texture.

     

    When picking up a slab to carry it, use two paint sticks -- one under the edge, the other on top -- to pick up the slab. That distributes the pressure from lifting and carrying and avoids tears.

     

    Check out Youtube . . . search for slab built pottery, platters, etc. You may find some videos that show how to make, use slabs. Visuals often work better than words when explaining this process.

     

    No need to give up. Learn from your experiences.

     


  6. I am having a major problem with warping platters and plates as they are drying, I use just a lot of different vessels as my molds, even glazed pieces, I try to keep them covered as they are drying. I use cone 6 clay from Standard, sometimes white and other times brown; I am getting to the point of giving up,as I am pretty new to this mud business, don't seem to be getting the hang of it. Any help will be appreciated


  7. Commercial glazes aren't all that bad. They can be layered or even mixed to come up with different colors, just keep track of the percentages of the different glazes. I, too, don't have 'chemistry', space to store all the dry ingredients, and maybe the discipline necessary. All the different ways of applying glazes can change how any one of the commercials look when fired.

     

    I have purchased glazes that I've intensly disliked and yet after mixing them with others ended up with some real winners. One example was called Cola Green. I didn't like it on my clay body, so mixed some with an end-of-a-bucket matte white and came up with a great beanpot brown.

     

    Remember, if you start mixing your own glazes, the first thing to buy is a good respirator. Stay healthy, and good luck!

     

     

     

     

    Ohhhhhhh, thank you so much for the info, I'll try mixing to see what I come up with


  8. I am relatively new at this "mud thing" and I want to mix my own glazes , but, I have not the faintest idea how to start,I get intimidated at just the thought of it, I've NEVER had any chemistry in my life, commercial glazes seem to be too expensive, plus they are too commonplace, can anyone explain in easy to understand directions? HELPPPPPPP please, it will be appreciated, P.S. does anyone know of any classes in mixing glazes in the North Mississippi area


  9. I'm beginning to have problems with the rims of my slip poured stoneware plates collapsing during the glaze cone 6 firing. It just started, I've fired in past with no problems, now they all collapse. The slip supplier said it is the same slip as the other that I purchased. I need help, badly; any input WILL be appreciated. Thanks

     

    Hi, I had the same problem with my thrown bowls and plates. Here is what I did:

    1. Check max. temp. with cones to see if the kiln is firing hotter than normal

    2. Check the thickness of the rims and side walls to see if you are making them thinner than usual

    3. Ceramic ingredients sometime are changed by the supplier because they switch to a different supplier themselves

    4. Is the moisture/wetness of the slip the same or is the molds are wetter than usual which can give you a thinner side wall

     

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