Saturday 28 April 2012

A test firing to cone 7

Here are a few results from yesterday's test firing. I say "test firing", because some of the glaze and slip combinations were experimental. The first photo is of the cappucino cup I showed unglazed in a previous post..it had the white slip applied after bisquing the black slip. 5% ferro frit was added to the transparent ash glaze as a flux, and on this piece it's cured the bubbling and pinholing problems..but i'm wondering if this is because I brushed it on very thinly. I also want test this glaze at cone 9/10, but I rather like the buttery, matt surface achieved at this lower temperature.


( It wasn't easy to photograph these slipped pieces, so the colours probably aren't 100% accurate. )

The next three pieces were combinations of black and white slips with the Leach 4321 glaze, plus about 3.5% tin. I was expecting that the glaze would come out semi-opaque at this temperature, as there's quite alot of tin oxide in there, but apart from some micro-bubbles, it's still pretty much transparent.





Where the black slip is partly covered over, it has a slight magenta tinge to it. Quite a pleasing effect, but I would like it to come through stronger and darker.

4 comments:

  1. Nice results with the slip and glazes, I like the matt mug and hints of magenta how wonderful. My kiln will go to cone 10 but I've only fired to a hard cone 6, one of these days I'll do some more experimenting. I tried sprinkling some ash on a glazed pot then firing it and the glaze came out crunchy and bubbly; someone advised me that ash doesn't melt till higher temps are reached so very interested to hear about your experiment.

    ReplyDelete
    Replies
    1. Thanks for the nice comment, Linda. Yes, I think ash on it's own requires at least cone 10, but as part of a glaze (here it was about 15%) it seems to melt at a much lower temp.
      My only problem at the moment is getting hold of enough ash!

      Delete
  2. You can try to take shots of your beautiful creations on a black or other dark background. It will be easier to see colours in photos... I hope.
    Nice work !

    ReplyDelete
    Replies
    1. Thanks..yes, you're right, I just don't have a suitable dark material at the moment.

      Delete