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MartinB

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  1. MartinB

    are there any green food safe glazes

    Ooooo.... Thats rather nice! The patterning on the flat I take it was some slip decoration or something? I love how it breaks to blue.
  2. MartinB

    are there any green food safe glazes

    I'll ship you my copy for the bargain price of £150 EDIT: On a side note for that book, there's some useful general information in it, then a reasonable amount of recipes for bright coloured 'clean' contemporary glazes covering low, mid and high fire. If you're more interested in the technical side of it I'd say the John Britt book is more comprehensive, covering glaze testing, firing cycles, loads more recipes, more traditional glaze styles and special effects (tea dust, celadon, tenmoku, oribe etc) If I was to pick one I'd definitely go with John Britt book.
  3. MartinB

    are there any green food safe glazes

    Not to be a downer but it might be a little optimistic to make a glaze from scratch and have it come out as you expected without lots of experimenting, and for it to be strong, safe and not craze down the line. Especially if its going to be used in a cafe, man handled, washed multiple times per day with harsh cleaning products, put in a dishwasher and microwave etc. I'd also be MUCH more concerned that you were going to use lead in a glaze than a bit of copper oxide or chromium, or that the base you picked is for a low/mid firing temp range when you're talking about high firing. If you are selling your wares its your responsibility to understand the chemistry and risks... I'd probably recommend buying a commercial glaze for the time being (not that that's a guarantee for a well formulated glaze, but go with the big brands), then get a couple of books on glaze making. John Britt's - The Complete Guide to High Fire Glazes is a very good starting point, and Linda Bloomfield - Colour In Glazes has plenty of greens and blues in. (And if you really get into it ceramics material workshop does some amazing online glaze chemistry courses)
  4. Yeah I don't really trust a clay body that's listed as cone 6-10... I know there's a few mid fire cone 6 porcelains in the US but I can't find any in the UK so its cone 10 for me.
  5. Some more info on clays/shrinkage and absorption https://www.ceramicindustry.com/articles/84673-ppp-clay-body-shrinkage-absorption https://digitalfire.com/4sight/glossary/glossary_functional.html
  6. Around 1000dec C (cone 06) is a common bisque temp for mid (cone6/7) and high fire work(cone9/10), you might go a bit higher or bit lower for various reasons but consistency is more important so just aim for 1000 to start with. Then find a clay body you are happy with that matures at the temp you've decided to work at. Most places do 1kg sample packs, order a few in and try throwing/building with them and fire them. Stoneware and Porcelain should not be absorbing water, or very little, if they are fully matured and vitrified.
  7. Is the porcelain you are using a cone 05 porcelain? Most porcelains are cone 6-10 (1200c - 1300c), cone 05 is 1046c so you are likely a long long way off your body being vitrified. If you are using 04/05 glazes you need a body that is made for 04/05 temps...
  8. What Min said, try glazing with only one glaze on both the inside and out, it might be that the glaze is not that compatible with your body. It could also be that you have different amounts of glaze on the inside vs the outside depending on which you dipped first. The body absorbs some water with the first one, then the second application doesn't draw as much water so you end up with a thinner coating. You could make sure the body is completely dry after the first dip, or give the second dip more time to build up a thicker coating. Depends on the thickness of your body, what temp you bisqued at etc Its a process of elimination. Good luck! Edit: Do you have a link to the glazes? Am curious about them being compatible...
  9. Have a listen to this podcast - Building a Community Center | Tallie Maughan | Episode 249 http://thepotterscast.com/249 Its the place I started doing pottery at in London, its gone from strength to strength and is a real hub for ceramics in the city now, they're even opening a second site too. Might not transfer over to what you're thinking but definitely worth a listen and probably some useful advice.
  10. I did see Cool Ice (^6 porcelain) listed on potclays website but its out of stock and £51 for 9.25kg!
  11. If only it was available in the UK I'd jump at it.
  12. Most online suppliers have a section for cone-6 glazes but pretty much all clays are just listed as stoneware and given a broad firing range. I'm interested in a cone 6 porcelain but there are none listed specifically as that, though several say 1240-1300 firing range. I assume at the lower end I would be sacrificing some translucency and strength... I've ordered sample packs of a few and am going to run some tests. I'm happy enough re-formulating my glazes to work at cone 6 but if I can't get a nice body I'll have to stick to higher firing.
  13. Yeah I've seen very few cone 6 clay bodies that aren't sold as firing from cone 6-10. Keep reading posts here about beautiful translucent cone 6 'Frost' porcelain but there's nowt in the uk.
  14. If you found the video interesting and want to know more about glaze chemistry and what all those numbers mean when you look at insight-live or glazy.org I couldn't recommend highly enough the Glazed and Confused course offered by Matt. Crazy amount of well presented information and a stupidly low price. I've had a vague understanding of what the numbers mean from reading various books and online articles but never explained so clearly in such depth with loads of diagrams. In no way affiliated but now a massive fan boy, hope you continue to release all the future courses you hint at.
  15. Thanks Matt, really interesting. Just signed up for your U.M.F workshop, looks a bargain for $10 and nice to see some technical tutorials!
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