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About jafa5

  • Birthday 04/19/1971

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  • Location
    Matakana, New Zealand
  • Interests
    Fermenting, brewing, distilling and curing meat

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  1. Thanks Liam, you're awesome! I have a small sample coming and will use it but given the extra risk won't pursue this any further. That said, I might half the sample and fire the second half as a dry powder to 300 or 350c to decompose the hydroxide so i'm left with straight cobalt oxide. Mark, yes it's a lot cheaper in NZ but not worth the extra risk. Mostly I'm just wanting to learn more about the chemistry, which is fascinating. I never did it at school unfortunately so a deep dive now which is cool. Mostly i'm interested in firing what I find locally in NZ and from the excavations at work (we are constructing an 18 km highway here) so have access to a wide range of clays, rock, volcanic ash and oxide seams. I've managed to track down a huge amount of local sourced materials country wide but still need to buy a lot of the colorants and more exotic materials.
  2. Thanks for the quick responses guys, really appreciated. I'll see if I can add it to Matrix and research "stoichiometry', that's a new one haha. I hadn't thought that the solubility would increase the toxicity risk but guessing hydroxide makes it soluble? Makes sense and probably why it's been mixed that way so farmers can spread it easily. Will check with the chemical company. I'm not in any rush if you do get a chance to stoichiometrisize it We're currently renovating an old bungalow, so pottery is way down the list of important jobs, when the boss says she needs the bathroom finished, it takes priority, most days haha Great time for research though even if I'm only firing test tiles. Be great if it decomposes to oxide (thanks Piedmont) but might still be too much hassle if it's soluble. I think I need to understand that better than I do. Cheers, Liam
  3. During a search for sodium molybdate I came across some cobalt variants in rural chemical stocks. I understand that cobalt hydroxide decomposes to cobalt oxide at 168 degrees c (thanks wiki) but I don't know how the decomposition will effect the glaze or how the hydroxide will effect the glaze mix. I'm about the find out but anyone have any understanding of it and she'd any light before I start? Cheers, Liam
  4. I was lucky enough to get some time with one of the geotech guys on site and they noted that its unlikely to have nephaline as a component from the Coromandel area (New Zealand) so substitutions would need to be made using a local feldspar - he is now finding me a local source of feldspar or feldpathic sand that might do the job :)
  5. I've sent an email this morning and requested an analysis sheet (with an example), fingers crossed. Rocky dust is ok Curt, I have a ball mill to make it into a fine powder.
  6. I have a few rock quarries an hour or so from home that extract Syenite for road construction, but the guys I've spoken to on the phone don't know if its nephaline syenite, to be fair they just called it rock and had to check if it was Syenite. I'm just waiting on time off work to run down and pick up a trailer load of dust to test, but in the mean time... Does anyone know what the effects would be in a clay body or glaze if its Syenite without a Nepheline component? A reduced amount of feldspar minerals? Cheers, Liam
  7. Great reading in this thread, I have access to heaps of clay as we are building 18km of motorway through the north island in New Zealand. Had some very good results to date with clays firing happily to cone 13 along with a few explosions of course. Nice to start understanding how I can run some tests in an organised manner instead my usual, rougher manner... Thanks for sharing and good luck with the Hudson Clay!
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