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High Bridge Pottery

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About High Bridge Pottery

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    Joel Edmondson

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  • Location
    Newcastle Upon Tyne. England
  • Interests
    Rocks and fire

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  1. Ian Currie Test Tiles Forums?

    @Joseph F There's no better place to post them. The thread started with Curts lack of finding a Currie tile forum so we started one here. I still remember the first tile I tried and spending 3 hours weighing out each individual glaze for each cup because I was clueless. Always generally interested in a test tile whatever you are testing out.
  2. Ian Currie Test Tiles Forums?

    I was thinking along those lines Pieter, maybe the SiC is adding more power to the other flux. There's no need to care about the bubbles but it is good to know they are still in the glaze and probably trapped by it being really viscous. Looking at the tiles it seems to me like the SiC is more like alumina than anything else, the high silica tiles with a little become more like a glaze you would find top left not bottom right. Iron reduction is to do with Fe2O3 > FeO Red iron oxide > black iron oxide
  3. Ian Currie Test Tiles Forums?

    I bet if you took a cross section the smooth ones would be full of bubbles. The pitting is just the beginning of them.
  4. Glaze Application Questions.

  5. Ian Currie Test Tiles Forums?

    So cool, would love to see them in person. Going to have to buy some SiC. It's interesting to look at them left to right increasing in silica. I wonder if the right side SiC contains as many bubbles hidden under the surface as the base tile.
  6. You're probably better off using 350 mesh anyway, I am not sure how much of a noticeable difference there's between the two, I think you could probably guess that it might 'look' like you fired 200 mesh silica half a cone hotter by using 350 mesh as the smaller particles will melt easier.
  7. Ian Currie Test Tiles Forums?

    I have a sheet that goes up to 6 'flux', would be nice to add a few more just in case but I never got round to it. Also calculates 7by5 and 5by5 grids. Copy/edit away. It doesn't actually work really well for doing them in typical currie grid style but good for picking 4 corner glazes of whatever and working out each square. https://docs.google.com/spreadsheets/d/11H0rugHScuaFXK1mg8xG_NJjIAUI33g3HBtsObT1AB0/edit?usp=sharing
  8. Ian Currie Test Tiles Forums?

    That's a lot less % than I was thinking, seems to make a noticeable change. @curt I feel it matches up with what I am noticing in general, more flux and less SiO2/Al2O3 is good for removing bubbles. Looking at the glaze I ran that had no visible bubbles it has 2.45 SiO2 and 0.34 Al2O3, also 0.18 B2O3 I think limit formula are looked at wrong a lot of the time, I see that a glaze with the lower limits is just as good as a glaze in the higher limits, it's more about ratio than boundary lines. A little while back Matt Katz was showing me Stull charts. Using that to compare my good glazes that are bubble freeish they all sit right on the corner of the white before the crazing area. If you follow that line it pretty much sits on the limit formula. I am not sure how anybody gets to the highest gloss area bubble free. Anyway I think my point is keeping the right ratio while dropping below the limits is more important than being in the limits.
  9. Ian Currie Test Tiles Forums?

    How much SiC is there in the glaze? It is a "refractory" thing so that work with the less melting and probably exasperates holding onto bubbles. I wonder if any of the carbon being oxidised out of the glaze, does that mean the glaze is being reduced then. Only speculating,
  10. Ian Currie Test Tiles Forums?

    I have done this when there's one glaze you want to run a lot of tests with. Mix up a big bucket to 1.5sg and then take out 240ml~ for each corner glaze. As long as you can measure the volume and it's well mixed I think it is accurate enough. (Weight of glaze - Volume of glaze) x (5/3) = Dry glaze : (360 - 240)x(5/3) = 200g dry glaze I use these numbers to get down to 75ml corner glaze instead and 25ml spare for when I mess something up.
  11. Test

    This is only a test, please do not panic
  12. Upcoming 300th Firing - Kiln Repairs

    I would guess the higher the clay the hotter the read as there's less mass to bent it. David, are you saying sputty's height is wrong? I think most people go to about that level.
  13. Upcoming 300th Firing - Kiln Repairs

    @Chilly Not sure they are much quicker to make as you have to merge the sausages into each other for a sturdy hold. I normally make a long coil and push the cones into one side, loop it round to the other and merge.
  14. Upcoming 300th Firing - Kiln Repairs

    Just the tip and only for a minute. I used to prod cones into lumps of clay. Somebody taught me to sit the cones on a flat surface and jam two clay sausages either side so the bottom of the cone is flush with the kiln shelf. Feels slightly more accurate way to get the right angle.
  15. Specific Gravity from Dry Ingredients?

    Googling Brongniart's formula a clay art post comes up first. Can you take this bit and say in a liquid of 1.5sg ~ 1 water : 1.25 dry material. That would mean to get a volume with 1.5sg you would need 200 dry for 160g water. Maybe it doesn't work, not sure. The volume part is confusing me.