Tuesday, February 7, 2017

Got Primitive

Day class on Anasazi pottery yesterday by Gene Hickman!! It was fun to see our finished replicas too!!  Gene has some nifty stuff on pinterest also.

Monday, February 6, 2017

February 5th Hint of the Week

Tips On Plates & Platters

 - Pottery Magic http://www.pottery-magic.com/

Making plates can be tricky, and the larger the plate the more likely you will encounter problems. Here are some remedies:
  • Make sure the clay is thick enough. Thinner plates are more likely to warp. Thickness should be even. Clay should be very uniform, work the clay well.
  • When rolling slabs, make sure you roll it out evenly in all directions, otherwise you could compress one side more than another and or have thinner places on one end or another.
    * When throwing, use soft clay but not too much water or the rim will get too floppy.
    * When you carry your wet clay slabs to a different place to form, make sure you don’t stretch it. Put it on a board, or roll it lightly into a sausage, then unroll directly on the mold that you will use.
  • Plates must be dried very slowly and evenly. Uneven drying can set up stresses that don't show themselves until the final glaze firing.
    * It can help to control drying so the center dries faster than the rim. To do this, cut a round hole in the plastic about 3-4 inches in diameter over the center of the plate.
    * Some people use water based wax to coat the rims during drying, to prevent them from drying too quickly.
  • For large platters, you probably need two foot rings, one around the outside and a smaller one left in the center. Otherwise the center of the plate may sag during firing.
    * When you place a platter on it’s rim, place it on soft foam to protect the rim and keep it from getting stressed.
    * Trimming large platters can cause slumping of the bottom during the trimming process. You can put layers of foam rubber or carpet pad into the center area before inverting * *  * * *Place a board onto foam rubber or rim then invert the whole thing to turn it over. This “holds up” the center area and prevents it from sagging. It is not necessary to fill the whole center of the plate. If you fill the center only (i.e. a 6” circular piece of foam rubber), it will keep it from sagging.
    * Another thing to use in a similar way is socks or larger fabric sacks filled with rice. The rice is malleable so you can push it around until you get the right shape.
    * Or still another item to use is a sponge.
    * Sharp tools make it much easier to trim without causing deformation. (Remember, clay has memory and even if you smooth out any deformations, they will come back during firing.)
  • Many people find firing goes much better when they notch the plates' foot rings. Warping, cracking, s-cracks, were all eliminated. The notches provided a way for air trapped under the foot to escape. If the gas can’t escape from bottom it may cause the center of the plate or platter to “bow” up. Just make small, U-shaped notches at the bottom of your foot ring.
    * Instead of, or in addition to these notches, drill small holes in the foot ring. This also allows the gasses and heat to escape, and also allows for a wire to be used for hanging. This is especially nice for plates that are too large to fit into standard upper kitchen cabinets. Some people use a single hole, others two close together, others 3 spaced evenly around the platter
  • For plates and other items with large bases, make a clay “cookie” at the same time as your piece. This is a sheet of clay (the same type of clay), which you sit your piece during drying and firing. The cookie and the plate will shrink at the same rate. This seems to keep the piece from “hanging up” on the kiln shelf during shrinkage, expansion and contraction. For extra assurance, put a wash of alumna hydrate on the feet and the cookie.
  • Another method is to cover the shelves with grog. The folks who fire the kilns will put the grog on the shelf under the plate, just leave them a note.

January 28th Hint of the Week

How to: Make a texture roller for clay

This project is instant gratification. Something that is not that common in the world of clay. With this texture roller, you can use it as soon as the hot glue has cooled, which is very fast. It’s a great project to do in a class, or on your own so you have a custom tool that no one else has.

§  a roller of some sort (cut up pieces of PVC, empty rolls of tape, couplings for PVC, plastic      rolling pins from the dollar store or craft store).
§  a sharpie.
§  a hot glue gun. They only cost a couple of bucks.
§  extra hot glue sticks.

Draw your pattern onto the rolling pin. It’s easier to work out the pattern before with a Sharpie than it is later with the hot glue. Think about some sort of connected pattern, they tend to have the best results. And don’t go overboard with the lines, you’ll regret it later. And remember that the hot glue line aren’t going to be perfect, so just go with the imperfection.

While you’re drawing, plug in your hot glue gun. Make sure that you do it on a surface that you can toss when done, like newspaper or cardboard. When you’re done drawing on your design, start gluing. Be a bit heavy handed with the glue. If the lines are too thin, they won’t show up on the clay as well.

After the glue seems cool, start rolling away… The first attempt might stick a bit, but after there is some dusty clay on the roller, it won’t really stick.

If you’re not a hand builder, a nice use for one of these textured slabs is in the bottom of a thrown and altered casserole.

For the throwers out there: If you use a small print roller with a handle to put the design on, you can hold this against the side of a freshly thrown pot while supporting the pot wall from the inside.

January 22nd Hint of the Week

More about Wax Resist 

 Partially from The Big Ceramic Store

·         Some people think that waxing the bottom edges of a pot helps keep the glaze from running off the pot. However, the wax burns off way before the glaze ever melts, so this doesn't help. The only purpose of the wax is to make it easier for you to wipe the glaze off, especially when you are “dunking” in glaze.
o   It does help to have an undercut or small break, like a foot, in the surface toward the bottom of the piece. This break will help stop most glaze at that point. But don't depend on it too much. Runny or too thick glaze can still run right over it or your resist.
·         Dip your brushes in soapy water or fabric softener before using wax resist, and the brush will be easier to clean. Good idea to wash them afterwards too.
·         Some people swear by dipping their brushes in Murphy's Oil Soap prior to use.
·         Once you use a brush for wax resist, don't use it for anything else. You might want to paint the ends of all your wax resist brushes a certain color.
·         People having trouble applying wax resist often are using it too thick. Try taking some into a separate container and thinning it with water. It dries faster and may work better.
·         Waxing under or around where lids fit, add alumina to the wax resist, keeps the lid from sticking, and may keep the glaze out if it is not too thick or runny.
·         One way to cover the bottom of a pot quickly and evenly with resist, is to use those cheap sponges on a stick often used for painting. You can get them at the Dollar Store, or pieces of the sponges out of the cone boxes. Unless you use too much pressure squeezing the sponge, you’ll have less excess glaze running down the side of your piece as when using a brush.
o   Like everything else in pottery it will take practice no matter which method you use.
o   Use the technique that works best for you.

Thursday, January 19, 2017

January 15th Hint of the Week

 When to use Magic Water? (From Lakeside Pottery in Stamford, CT)

Magic water is used when the bond between two pieces of clay is a suspect for cracking during drying or bisque firing. Cracks can occur in the following conditions:
  1. When one piece of clay dries faster than the other which typically occurs when it has a smaller mass or thinner than the other piece (e.g., a mug handle).
  2. When one clay piece is applied to another piece that is already a dryer leather-hard (e.g., when waiting is required for a thrown pot to harden before applying hand-built piece).
The above two conditions are more susceptible to cracking because when one piece is dryer that the other, it is therefore shrunk more than the other and will not continue to shrink uniformly after they are attached to each other, thus - creating stress.

Consequently magic water is great for mixing with your clay to make “magic” slip to attach all your handles, spouts, sprigs, etc. It really works better than just plain water in your slip mix. So Magic Slip could be your go to slip for all attachments.

Magic Mud? Magic mud is the same as your slip, magic water and clay, but it is thicker almost like toothpaste. Magic mud can be used for more extreme cases. It enables the joining process to be less critical and therefore one can build more spontaneously as well as build wet clay on dryer clay. You can fill in stress cracks during drying and additional stress cracks will be reduced dramatically. It can also be used to connect broken bone-dry pots / sculptures. Sometimes it works fixing broken bisqued pots (needs to be re-bisqued after applying magic mud). When fixing broken bone-dry or bisqued pot, always apply more magic mud / magic slip than needed and build the layers slowly allowing the layers to dry in between applications. The excess slip can be filed down after the bisque firing.

Why does Magic Water work?
Sodium in the soda ash and the sodium silicate is a very powerful flux. The silica in the sodium silicate adds some glass-former. The water is to dissolve the soda ash (which is soluble) and therefore travels a little way into the wet clay. The sodium silicate is sticky and dries really hard and faster than the clay does. The end result is that the Magic Water makes a sticky layer of almost-glaze that soaks into the surrounding clay and dries hard. Thus, cracks are prevented in the drying and the bond is stronger after firing.

We keep a couple of milk jugs of magic water made up and on the shelf in the ∆10 glaze area. Bring a small container and take what you need for mixing in your slip. It is cheap and easy to make and we try to keep the magic water jugs full.

Thursday, January 12, 2017

Hint of the Week for January 8th

  Some Glazing & Decorating Stuff from Pottery-Magic.com.

·         Before you begin glazing always be sure to wipe your ceramic piece down with a damp sponge. This will make sure that there is no dust on your piece which could cause the glaze to pull away and leave a bare spot. Dampening helps the bisque to accept the glaze.
·         If you are painting on glaze, you must paint on three flowing coats of glaze, being careful of brushstrokes which could show up in unleaded glazes or if you use less than 3 coats. Three coats of glaze will give you a solid color. Adding another glaze for the second and/or third coat will give you some interesting effects. Let each coat dry before adding a second.
Best to brush in opposite direction
·         To show textured surfaces better, brush glaze on so it gets in all the cracks, then wipe off the top surface.
·         To remove oxide mistakes or for making a design, use a pencil eraser. It won't smear like trying to wash the oxide off.
·         When applying oxide over dry glaze, the glaze sucks the water out of your brush making it difficult to paint clean lines. To remedy this, lightly mist the glaze first with water and the oxide will flow smoothly.
·         When glazing a thin piece, glaze the inside then wait for it to dry thoroughly before glazing the outside. Otherwise the clay will become saturated and your piece will either fall apart because it will have absorbed so much water or the glaze won't absorb and stick to the outside. Sometimes it is best to at least let it dry overnight before glazing the outside.
o   [This is a common occurrence, for instance, when you glaze the inside of a cup with one glaze and the outside of a cup with another glaze].