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Dick White

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  1. Dick White

    Most used sieve size?

    I have a 30 mesh sieve that I use occasionally for really lumpy glazes, or to resieve a hardpanned glaze. It breaks up the clumps and everything passes through quickly in far less time than I would need to scrape it directly through the 80 mesh screen.
  2. Dick White

    Engobe for decorative use on bisque

    Yes, clear glaze over colored engobes, slips, and underglaze patterns is quite common. Whether it will be smooth in the end is a function of the smothness of the application of the engobe.
  3. Not to be a stick in the mud (very very bad pun, naughty boy, go to your room and don't come out until you have picked up all your toys...) but a concern with the stick (or whatever) in the blob of clay on the edge of the splash pan is that if you are going to do a long production run over a considerable length of time, the clay will begin to dry and shrink, and the pointer end of the stick will move. The movement will be imperceptible from piece to piece, but the size of the last piece of the day will not be the same as the first. If you don't mind spending a bit more than a trip you your favorite coffee shop to snitch some extra stirring stick Hsin-Chuen Lin (of UBoob video fame) markets a metal adjustable tombo gauge with measured markings and an alternate configuration of the tool to measure the thickness of the bottom of your pot before you trim (so you know exactly who deep you can trim your footring).
  4. Dick White

    Older Bailey Slab Roller value?

    Does it click when you roll it? If it clicks, there is a ratchet and pawl somewhere. Is the big hand wheel screwed on its shaft by left hand thread, i.e., it advances the clay through the roller (left to right) by turning the hand wheel counterclockwise? If so, when you turn the handwheel clockwise, do the rollers turn or does the handwheel simply unscrew from the shaft? BTW, notice the red sign on top with the big arrows point to the right. The label says it should go only that way.
  5. Dick White

    Older Bailey Slab Roller value?

    All have the chain and sprockets, the difference is where/how the handwheel and its drive shaft enter the drive train. And yes, you can smash any wad of clay in one pass with this beast, but IMO you shouldn't. Rolling a slab stretches it in the direction of the roll. Clay memory will cause it to later shrink back more in that direction. So, a slab rolled in one smash and then cut to a perfect square/circle will end up as a rectangle/oval. A better technique is multiple rolls in multiple directions. You can't really do it like the manual rolling pin brigade, flipping it and turning it and rolling every which way. Here you have to roll in increments, and turn (and flip) the developing slab as you bring it down in thickness. That also means picking it up from the output table and bringing it back around to the input table, and doing some mental gymnastics along the way so it doesn't get so long during an interim pass that you can't turn it and still fit it within the width of the roller for the next pass. In the video, that was a nice parlor trick Mr. Bailey showed us, rolling a perfect slab the exact length and width of the table in one roll, but the kiln gods are waiting for a smackdown on that with some uneven shrinkage.
  6. Dick White

    Older Bailey Slab Roller value?

    Yes, that's Mr. Bailey himself. We have 2 of them in studios I work in. One is way-old, the other brand new last year. And yes, they must be rolled from left to right ONLY! On the older model, the hand wheel turns clockwise, and the slab moves as if the rotation of the hand wheel is pushing it through. There is a ratchet and pawl on the lower roller that prevents you from turning the wheel backwards. Unless you force it and bend the pawl pivot (which students have done several times over the years, then you have to disassemble it and repair the pawl, until it breaks and then you must buy a new one, $32, don't ask how I know the price...). On the new model, the wheel turns counterclockwise, visually contrary to the motion of the slab, but you get used to it - pull back on the wheel to make the slab go forward. There is still a pawl and ratchet on the lower roller, but now you can't turn the roller the wrong way by turning the wheel backwards. Now the handwheel is threaded (left hand thread, to be exact) onto the drive shaft rather than affixed by a set screw on a flat of the shaft. Thus, if you turn the wheel the wrong way, it will simply unscrew itself (and if you turn it enough times hoping it will finally draw the slab backwards, the wheel will fall off and break your toe. Lesson learned yet?)
  7. Dick White

    Celadon - Application?

    Alice, I will refrain from getting you started on the commercial "celadons" if you will excuse me for starting a similar rant about the line of "shinos" from that other commercial purveyor...
  8. Dick White

    Skull E-1 error question

    E-1 is failure of the temperature to rise. If the room temperature got to hot for the controller board to function properly, the error would be E-bd. The most common cause for an E-1 error is worn elements. The amount of power needed to raise the temperature in the kiln increases as the temperature goes up. It doesn't take much heating power (relatively speaking) to get to bisque/low fire temps. But it takes progressively more heating power input to get each degree of increase. Thus, you can run a kiln for bisque/low fire only forever, but it will fail if you try to take it much higher. You can check the resistance of the elements with an ohm meter. A second cause could be that one element is broken. A good kiln like Skutt can reach bisque/low fire temperatures with one element out. But then, as with worn elements, it just can't go any farther. Another cause could be a relay stuck in the off position. The controller is telling the relay to turn the elements on, but it's stuck and doesn't, so the kiln doesn't heat. That can be more difficult to diagnose as it might be intermittent. Check the elements first.
  9. Some practical considerations regarding kiln wash: Wash only the top side of a shelf. The bottom side of the shelf should be bare clean shelf so that chips of wash do not fall off into the glazed work on the shelf below. This also means you cannot randomly flip your shelves in the hopes of evening out warpage. If you wish to flip a shelf, you'll need to clean off all old wash from what will now be the underside of the shelf. When you apply the wash, keep it 1/2" or so away from the edge and do not let any dribble over onto the edge of the shelf. Those little drips will get knocked loose while handling the shelf during loading and will, like chips from the underside (see above) inevitably fall onto a piece below. Use a wash recipe that is known to be solid and not peel and flake off. My preference is 50% alumina hydrate, 25% kaolin, 25% calcined kaolin. Some also add 1% feldspar just to help it fuse to the shelf better, but I haven't needed that. dw
  10. Dick White

    a quick question about Process

    Magic water is a very mild deflocculating solution that seems to open up the surfaces to be joined by the same process of creating similar (and consequently repelling) ionic polarity of the clay particles, thus allowing the joining surfaces to intermingle better. Deflocculated slips have two characteristics of interest - 1) obviously a deflocculant is involved, similar to magic water, and 2) the deflocculation allows a lot more clay to be incorporated into the same volume of slip, making for a stronger and drier (less shrinkage) joint. Vinegar, a mild acetic acid promotes adhesion between the surfaces of the parts to be joined. Which is better depends on who you ask. I take it a step further by using a paper clay slip made with vinegar rather than water. Plain water and the paper fibers will quickly turn to black mold if kept in the wet state, but vinegar instead of water will effectively pickle the paper fibers so you can keep a tub of it ready to immediately use as needed. And the vinegar does double duty for adhesion.
  11. Dick White

    Re-firing low fire glaze

    If you are using commercial brushing glazes, the brushing agent that makes them brush out smoothly is usually an organic gum (CMC). That also will help the glaze to stick to a previously fired glaze surface. You probably don't need the hairspray trick. That's typically for dipping glazes.
  12. Dick White

    Dry wood ash on glazes

    I never tried it with other glazes. It works well with shino, didn't take it further. Maybe something to try? The Simon Leach method of wetting the ash will take you in the direction of washed ash (there is a whole body of knowledge with washed vs. unwashed ash in ash glazes) and the atomizer will give you a finer distribution of the ash on the side of the ware. And the blue spot is just a finger touch of blue glaze for visual interest.
  13. Dick White

    Dry wood ash on glazes

    No, sadly only 10. My shipment from from Dune was hijacked. And besides, like Custer, it ain't what it used to be, so I had to reformulate it.
  14. Dick White

    Dry wood ash on glazes

    I don't have my photo cube set up, so here is a thumbnail sketch...
  15. Dick White

    Kiln firing variations

    I have heard (but with no scientific proof offered, as I learned of this during a BOGSAT (bunch of guys sitting around talking)) that on a rainy day the water molecules in the ambient humidity are cracked by the intense heat and release some additional energy, whether from the broken molecular bonds or from additional combustion from the now-free hydrogen. FWIW, YMMV. dw
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