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Transparent crackle glaze

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  • Transparent crackle glaze

    I am new to the world of making glazes and am trying to get a transparent crackle glaze working on a stoneware glay.

    The recipe is:

    Alkiline frit 80 gms
    Nepheline Syenite 20 gms
    and for every 100gms of the above add
    80 gms/ml of water

    This recipe is from the rakuvaria 2 book. It also suggests glaze additive but I am not sure what that is or how much to add?

    The boolalsosuggest a temperature 0f 960 but I am note usre how long to maintain that temperature before moving to the reduction chamber?

    Many thanks for any advice.

    Pete

  • #2
    is this a stoneware glaze? It will need to be fired to 1260 if using a stoneware bodied clay. Sorry I can't help with the glaze, the only crackle glazes I've used were ready mixed out of a pot

    Comment


    • #3
      Hi Pete,

      I wouldn't worry too much about the glaze additive, I use this glaze and don't put anything else in except the main materials. I have had some success with this on a stoneware clay that is bisqued to 1000oC.

      Another raku recipe you might want to try and that gives good crackle results is

      85g High Alkaline Frit
      7.5g Whiting
      7.5g Ball Clay
      100ml water

      Hope this helps

      Eileen

      PS. I have replied to your other thread as well
      http://www.decimadesigns.com

      www.decimablog.blogspot.com

      Comment


      • #4
        The glaze recipe suggests the glaze temperature is 960 and is suitable for Raku firings which my kiln can accommodate. The stoneware pots had previously been bisque fired.

        Comment


        • #5
          As far as I recall from my Raku dabblings (which were a long time ago) the pots have to stay in the (pre-heated) kiln for about half an hour or so, until you can see that they are white hot (by peeking through a peep hole). Then you remove them with long tongs and gloves and chuck them in the sawdust!

          I'm sure others will correct this if I have disrecomembered!
          Daesul

          http://www.clairemanwani.com
          http://www.folksy.com/shops/clairemanwani
          http://www.etsy.com/uk/shop/ClaireManwaniPottery

          Comment


          • #6
            Originally posted by Daesul View Post
            As far as I recall from my Raku dabblings (which were a long time ago) the pots have to stay in the (pre-heated) kiln for about half an hour or so, until you can see that they are white hot (by peeking through a peep hole). Then you remove them with long tongs and gloves and chuck them in the sawdust!

            Yep, that just about does it Daesul!
            http://www.decimadesigns.com

            www.decimablog.blogspot.com

            Comment


            • #7
              Many thanks for your replies.

              I mixed the glaze tonight but was concerned that the solids dropped to the bottom so quickly. I added just 2gms of wallpaper adhesive to the mixture and was amazed when it appears to support the mix for a longer time. It was also a nice smooth single cream consistency. One of the other potters who seems to have a background in chemistry suggested that with the paste part of the mix being a protein, it will just burn off in the firing and if anything assist in the crackle effect be creating greater tension with the clay body as the thermal shock starts?

              I am planning to apply the glaze to some test pots this weekend for a firing and will report back my results.

              I will also try your suggestion from my other posting and watch for the glossy look to the surface. I will also check with the pyrometer to see at what indicated temperature this occurs at.

              Comment


              • #8
                I fired again last night using the glaze recipe mentioned previously. I used the wallpaper adhesive as a suspension agent which made the galze very smooth and workable. I only used 2 gms in a total volume of 500 gms of glaze mixture.

                I fired up to 970 which I then held for 12 minutes until the glaze as viewed through the ghimney was glassy and smooth with no bubbles. The reduction chamber had shredded paper.

                I now need to work out how to get a consistent finish over the whole pot.

                A picture of 3 of them where the glaze seems to have worked:

                Comment


                • #9
                  I forgot to mention that with the front and right pots there was extra crackle where I took the pots out of the kiln with the tongs. It seems that added pressure has enhanced the crazing effect. I quite like the effect. I need to experiment with this some more.

                  I love the crackle effects random patterns.

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