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dee kat

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Everything posted by dee kat

  1. dee kat

    Yellow Ochre

    Yellow Iron Oxide and Yellow Ochre are not the same. One is an Iron Oxide and the other is a clay. Go to digitalfire.com for checking materials and not wiki.
  2. dee kat

    food safe?

    This is not a glaze or a slip. It is a colorant wash. Much as when you use Iron wash on a body, it might react with the body and possibly lower the melting point of the clay causing a metalic sheen but it in no way qualifies under any definition as a glaze or even a slip.
  3. A note: If you use too much epson salt or Magnesium (what ES is) then it will go in the opposite direction. You need to titrate (add a little at a time, stir thoroughly and if there is no change in the glaze (it will thicken very slightly) then add a bit more. This is why the epson salt needs to be completely dissolved in the hot water before adding. If it were not, it would dissolve in the glaze over time and possibly tip you over the edge. If you know for sure how much you need then you can add it dry when you are mixing up the glaze. You must have enough clay in your glaze for the glaze to floculate (this is what you are doing by adding the Epson Salts). People add bentonite when they do not have enough clay in the glaze already. It is also clay that has unique properties so aids in keeping the other materials suspended.
  4. dee kat

    Kiln Help - Can I build one?

    Making a gas kiln I would think would be easier than an electric but much harder to fire. Simon Leach has taken an old electric kiln and turned it into a gas kiln (propane). You can usually find old electric shells that people want to get rid of because the controller has died. If you do go the route of rebuilding an electric kiln then you are going to have to control the temperature. For the old kilns before computer controllers that was done by turning different numbers of elements on to either low, medium or high heat. So you would start out turning the bottom element on to low for a given time - for greenware you would often candle overnight so this would be on low with the lid propped open an inch or so. The next morning the lid would close and you would turn the second element on to low and run like that for an hour then the top would be turned on to low. Each hour would turn one switch up one level of heat until all were on high for all three elements. You would have a shut off switch that was kept open with a cone of the temperature you wanted to fire to and when that cone bent the setter would fall and the switch would flip to turn the kiln off. There would be a timer that turned the kiln off after a maximum number of hours as a safety measure. Any sane potter would know the timing of the firing and would check at regular intervals to make sure the kiln had not shutdown prematurely or failed to shut off when it should (so there were always witness cones on the shelves that you could look at the check your firing heat work (something close to temperature but not really). So other than the shell you are going to need 3 sets of electric coils that will fit your kiln and a means of turning them on and off. You will need cones for monitoring your temperature. If you are going to do ramping or soaking then you are going to need to learn more than just turning on the elements and firing at high until you reach temperature. There are many posts on doing this with an electric kiln without a computer controller but you will need a pyrometer. Youtube is good for this type of information. Somewhere I have the one on rebuilding an electric kiln but I can't find it at this time. http://www.youtube.c...c.1.6iocYTycIL8
  5. dee kat

    Leaching & Unsafe Glaze Surface

    I recommend you read Mastering Cone 6 glazes and what is on this site. http://www.frogpondpottery.com/glazestability/stableglazes.html You can have a glaze that is matt because it is underfired (and therefore not good to put liquids in or on that are to be consumed) or ones that are matt from crystal formation, which is what you get from the matt recipes in the MC6 book. My favorite glaze is Bone which does wonderful things with just about every glaze I have tried it with. I once casually used the term food safe (meaning a stable glaze) when referring to a MC6 glaze and was called on it by one of the authors. I will never use that term again. However I would say that any glaze that is only using iron or tin for its colorant or opacifier (and doesn't have lead or barium as a flux) isn't going to be much different than what we cook food in (glass casseroles and metal pans). IMO we have gone a little nuts on the 'food safe' issue. You want a glaze that is not going to change with normal use. A cup should not change color because you put it in the dishwasher or used it for orange juice.
  6. dee kat

    Software For Glazes

    . You need to know if you are getting win7 64 bit or 32 bit. Many older programs will not run on the 64 bit win7. I use insight (also wrote my own program for glaze calculation) and think it is the best one out there not only for the software itself but for the database that is on digitalfire and the support you get from Tony Hansen. He does regular upgrades and I have had no problem with it at all on win7 64 bit. http://digitalfire.com/insight/index.php I could never get use to glazemaster (I think because it was more Mac than PC) but the support you get from the authors is priceless. http://www.masteringglazes.com/Pages/GMcoverandintro.html However if you want freeware then any glaze calculator that works with excel would do fine on any windows version as long as you have excel.

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