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Vsmithpots

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About Vsmithpots

  • Rank
    Newbie

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  • Website URL
    http://www.westcotebellpottery.com
  • Skype
    vsmithpots

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  • Gender
    Male
  • Location
    Nova Scotia
  • Interests
    pottery of course, everything about it.
  1. Underglazes Flaking Off

    I have been seeing this problem for the last 4 years. I fire at cone 04 and also at cone 6. I use the same underglazes for both on red clay and white clay at cone 04, on Bmix5 at cone 6. The cone 6 work just fine but the low fire flake/ shiver at cone 04. Sometimes the underglazes flake off the flat areas on tiles as well as the sharply curved areas like rims and handles. I think it is due to two seperate issues. Firstly the glaze for both temperatures contains Gerstley Borate, more at cone04 than cone 6. GB can help solve crazing issues in a glaze but if added to excess it can cause shivering, the opposite to crazing. If you add to this physical characteristic of the glaze, the underglaze issue of flaking, you can see how the underglaze can be forced off. However, underglaze should be adhered to the clay body by melting to it. Therefore it seems reasonable to assume, since mine work fine at cone 6, that at cone 04 the underglaze is not melting to the clay body. I tried firing to Bisque 01 and the issue mostly disappeared, the deep greens still flaked as if unmelted to the clay. I realized that these two colors were very old pint jars that had settled out repeatedly over the years. I add water and stir them but they settle every time I open the jar. I think that old underglazes may change compositionaly as they are used, heavier particles settle, lighter particles get used up since they are at the top of the jar. I have been guilty of not reading the label instructions, which, clearly state to stir thoroughly before using. To sumarise I think that underglazes should be bisque fired higher to melt them to the clay body. Secondly glazes with GB should be balanced by replacing the GB with Fritt 3195 to reduce the glaze comression on the clay body. Thirdly the underglazes should be stirred vigorously every time used. Old underglazes should be modified by adding fritt 3195 if they seem to be settling out and flaking. Adding a suspending agent to the underglaze should also help with settling issue.
  2. Estrin Potters Wheel

    I do live in Nova Scotia. I bought this wheel and it is working fine, but the drive wheel has very hard rubber, so it vibrates just a touch. I assume a newer rubber drive wheel will be smoother. I have 11 potters wheels, Brent, Creative Industry, Shimpo, Amaco and Pacifica, for some reason I love the feeling of the Estrin wheel. It is like the difference between a manual and an automatic car, I can throw faster on any of the other wheels but the challenge of the Estrin wheel is preferable to me. After 40 years on potters wheels I like the challenge. It does not have the whine you describe and I only engage the motor for centering, the flywheel has enough momentum for anything under 2lbs weight, most pieces need foot braking to take them off the wheel. I will attach a shield to the motor, thanks for the heads up on that. I will also try turning it around and attach the seat to the other side, so that the motor is out of reach.
  3. I have an Estrin pottery wheel with a large steel fly wheel driven by a rubber drive disc attached to an electric motor via a 5/8inch shaft. Where can I buy these drive discs? It was manufactured in BC. It works fine but I always think ahead. I trained on one of these 40 years ago so it has nostalgic appeal.
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