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njabeid

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  1. Oh well, here's another try. Dear Wise potters, thanks! You were right: after tweaking the engobe recipe, using local whitish clay as slip, slowing the bisque firing and also slowing the glaze firing now my pots have only some very small pinholes. That involved some protracted procrastination, while I indulged in other techniques, and then 'forgot' to add cobalt to the glaze. That's now done. Three cheers! and thanks again.
  2. What do you mean by reset? If it worked this time maybe the problem is at the other end? I have been trying to send you all un update, and finally got it to upload photos and actually look as if it had been submitted. So odd. See what happens to this one.
  3. Hello, why can't I post? I have written stuff twice, and it all disappears
  4. @Bill Kielb sorry, I’m afraid I don’t use cones here, The discussion has been more about pushing the firing time to get rid of the carbon etc. It looks positive, combined with a change in the white coating.
  5. @Min I added 10% zirconium silicate.. yes, these mugs are better, so way to go. But I’m not sure about the buff colour of the slip. I’ll go back a step and try the new slower firing schedule with different combinations. Not sure about the pinholed interiors though - the slower firing should have reduced degassing, instead there are now pinholes where there were none. Interestingly there are far fewer and smaller pinholes in the coffee cups with no slip, same glaze inside.
  6. OK, so the firing is done, and results and feelings are mixed. Somehow I feel lost and have forgotten where I was going. Anyway, the cups and mugs were fired with Min's schedule, i.e. 110C to 700C no soak. 2) 50C to 900C no soak. 3) 42C to 1000C no soak. They all have the homemade slip ("K-slip). 1) K-slip brushed on while still damp, dipped in GT1 (my glossy transparent). No pinholes but cracks at the bottom, and a piece of slip missing. 2) K-Slip sprayed while damp, sprayed GTI + 0.3% CoCO3 . Kinda OK 3) K-slip + 10% WrSiO2 sprayed damp, and sprayed with GT1 + 3% CoCO3. (Inside is a poured commercial clear with added opacifiers. I was using it up. Lots of pinholes inside in nearly all. Something went very wrong with the pouring in this one.) There's a big kind of burst bubble and one pinhole. 4) K-slip + zirconium sprayed dry, and sprayed GT1. Definitely the best, albeit not any whiter, but very pinhole inside. 5) K-slip with 0.5% CoCO3 sprayed dry, and dipped GT1. 6) I'm afraid I missed writing down the slip part, but it was applied dry and sprayed with GT1 + 0.3 CoCO3. Clearly visible two little blow-outs; a few pinholes. Coffee cups: One was dipped in K-slip while leather hard ... big mistake. It almost melted pathetically to a puddle, handle cracked, but the result the front cup in the picture is better than all the others, which were brushed with a hake brush; big mistake: I touched up the edges with the wrong glaze. All sprayed GT1 on the outside and poured opaque stuff inside. Better just have the same inside and out. Even waxed, edges are tricky with two glazes. So - conclusions: 1) The slower firing is good, I'll stick to it. But we changed two variables. 2) There is still a small issue with cobalt. My spray gun is a cheap thing, and makes the slip blotchy. 3) Slip works, but is far from white . Do I like the buff colour? It is too coloured to take colour kindly, but I'm going to try adding some yellow iron oxide to push it a bit further into a more interesting look. Maybe try something besides cobalt. 4) I didn't dip any dry pots - must check whether the stencil will stay on. 5) I wonder why the interiors pinholes so badly. Need to make the surface smoother. There's more to work on, but thanks to you all I have learnt a lot and am on a track to improvement. These cheered me up a bit though: Thanks!!
  7. For some reason my posts seem to be disappearing. @BabsThanks, I have one - it's just a bit Mario Bros working with clay drying around the edges in minutes. And hands! @Min I'm being optimistic. You never know, something could work out. Anyway, my pots never ever turn out the same as test tiles.
  8. @Min Thanks! I’m being optimistic. Some might even turn out OK…
  9. @Babs I have one, it’s super useful, but the rate of drying is mind-bending, Including one’s skin!
  10. It's the Sahara. Look up Nouakchott. Yesterday I wrote a post that doesn't seem to have been uploaded. It was about the ongoing tests. Various methods of applying the home-made slip, and various glazing methods and additions are all now cooling in the kiln. I'm very excited and hope it will not be too disappointing. True, several variables are changed at the same time (firing schedule, slip, additions, application methods, but it will be interesting and open up new avenues of research. This was the bisque fired pots, looking good.
  11. Thanks! I'm aware of that. Just responding to Min's mention of Epsom salts. It's the deflocs I'm after now. Let's see how the slip holds up - maybe I won't need to deflocculate.
  12. @Min I always use Epsom salts, but so far have not felt the need to deflocculate anything. I'm sure I'll find something.
  13. @PeterH yes, my mind was wandering along the lines of a chemical way to get rid of the carbon / organic stuff, thinking « caustic soda, but not practical for one’s hands »
  14. @Rae Reich no, the runny glaze was extremely simple, no rutile. I do like to add a pinch of rutile though
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