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Min

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  1. If the wheelhead rocks because the wheel is on 4 feet on an uneven surface or because the top bearing is shot that's going to cause a problem with an uneven rim. Liam, try the experiment in the video but just put the wheel slightly out of level and see how it turns out. Also, we've probably all had uneven rims when starting out, that's from a different issue though, uneven pulling of the walls. All things being equal, if you don't have wobbly rims with a level wheelhead you won't have a wobbly rim with an unlevel wheelhead as long as the wheelhead itself isn't wobbling.
  2. Will this do? https://www.youtube.com/watch?v=WNKwscKjtCc
  3. Wax resist is applied to leatherhard pots then when the wax is dry you carve through it and brush underglaze onto the pot. Underglaze stays in the carved areas and gets wiped of the wax resisted areas then the pot is left to dry then bisque fired. Wax burns off in the bisque so glazing goes ahead as usual. (single firing aka raw glazing pots would't work with this method) Brand of wax resist makes a difference, some wax resists work better than others. Welcome to the forum
  4. Really unusual, I've never heard of this happening, curious to know if anybody else has had this happen? @suzannajean, could you post a picture of one of the glazed plates and a bit more info on your clay and if you are firing it to maturity?
  5. @SweetheartSister, another approach would be to fire them unglazed to your glaze temperature then use a lowfire glaze and stilt them how you already do when making them with earthenware. Since the clay will be vitrified when you glaze it I would use a brushing glaze, it will take longer for the glaze to dry between layers though.
  6. Good to hear the clear is craze free. Matte glazes are fully melted when done properly. Sometimes though people are using underfired higher temperature glazes that are immature and under melted to achieve a matte surface. Either way the coe figures don't work. In the former, some of the matting agents precipitate out of the melted glaze matrix. If you look at what's in your white glaze you see both dolomite plus talc so basically this is a magnesium matte (with some calcium which can also be a matting agent), and we know magnesium is a low expansion flux. So in theory some of the magnesium isn't going to be in the remaining glaze melt, does this mean the theoretical melt will then be a higher coe than indicated by the math, perhaps, but there isn't a way to quantify it. This is why I suggested doing the cylinder tests. Reason I asked about your clear is if it had crazed then you could try dropping the expansion of that one fairly easily instead of the possibility of needing to alter the matte recipe(s). If you're not confident with your last round of testing then I would do one more round, make the cylinders thin, glaze heavily and see what happens.
  7. I believe you need to apply and fire the metallic gold lustre on first and then apply the mother of pearl and refire. Hi and welcome to the forum
  8. Make them as thin as you can, if necessary slab build them. "However I have adjusted the white glaze and substituted some of the tin for zircopax...it has brought the COE up to match the inside glaze more closely" If this is the Satin Matte White aka Pikes Oatmeal the coe figure won't be valid as calculated coe values only work for a fully melted gloss glaze. Does the clear gloss glaze craze when you test it?
  9. Couple thoughts, first off, I've never seen the Ron Roy Licorice glaze using 2 cobalt oxide. I believe it started out using 1 cobalt carbonate then a version of it using 1.5 cobalt carbonate but never 2 cobalt oxide. To switch from carbonate to oxide multiply by 63 and divide by 93 so if you take the higher amount of 1.5 cobalt carb and want to use cobalt oxide instead you would need 1.02 grams so basically 1/2 what you are using now. You don't want to be using heavy metals in higher amounts than necessary. @Hulk, it wouldn't be accurate to compare the coe values for a few reasons. Outside glazes include a matte, coe figures don't work for mattes as some of the materials precipitate out of the glaze matrix to form the matte surface or they are matte because they are actually underfired gloss glazes which again means the coe figure isn't accurate as it isn't a fully melted gloss glaze. I agree with what Mark and Dick said, decrease the total thickness of the areas using multiple glazes. To check your mugs before selling or using them take a few of them, the ones with the thinnest walls, and freeze them overnight then put them in the sink and pour boiling water into them.
  10. I'ld just ask Fusion where you can find those frits in Europe, contact info link here. If they are not available in Europe then what strontium and barium frits do you have access to?
  11. I have contacted both Mason and Ferro (includes Cerdac, Degussa and Drakenfeld stains) requesting info on their stewardship practices in regards to cadmium inclusion stain manufacturing. If I hear back from them I'll post their replies here. Does anybody have any literature on the processing practices of cadmium inclusion stains? From this link at Digitalfire: "... stain is further rendered safer-to-use by washing with water or weak acid to remove any soluble uncombined compounds (e.g. cadmium or soluble impurities). This washing process does produce toxic byproducts that can only be tolerated in certain countries (e.g. India, China)." Considering the toxicity of Cd this is an ethical issue for me, if Mason or Ferro do corroborate what Tony Hansen is saying on Digitalfire then I will no longer be buying underglazes that use Cd stains. I do hope you are correct Pres in that the mining practices will be changing and child labour will no longer be part of the equation. I will gladly pay more for it if I know it's ethically sourced. BTW @liambesaw, even at $50 lb that's still about 1/2 of what it costs if I buy it from my local ceramic supply place (which I don't). From my local place's catalogue "Cobalt Carbonate .................. 500 grams 92.10 Cobalt Oxide ...............500 grams 102.00 "
  12. A flip top table with an accessible opening underneath should work. If you used something like a pneumatic stool underneath so when the mold was flipped over you could push the stool underneath it and raise it up to support the piece then undo the strapping and roll it out.
  13. I have used Critter spray guns for a number of years and find they work well. I use them at 40 psi for glazes. It's a simple siphon feed (aka bottom feeder) spray gun as OldLady posted about. I toss the glass jar that comes with them and use a pint plastic jar, the type commercial glazes come in work well. If you do get a Critter and use a plastic jar, the lid that comes with the Critter needs to be replaced with the lid from the plastic jar. Just use the old lid as a template for drilling a few small holes in it then reattach with the tiny set screws that come with it. https://www.amazon.co.uk/Critter-Spray-Products-22032-Syphon/dp/B00006FRPJ
  14. I think I would work out some sort of jig to fit the slump mold in so you can pivot it upside down. Closest I could find of this type idea is this Rotating Slip Casting Table. I'ld make it with a few alterations, forget all the slip casting stuff in the video for starters. Make it so the cradle is just a bit taller than your slump mold. Have the slump mold on a piece of plywood with some holes drilled around the edge then have another piece of ply (same size) across the top of the mold. Put the mold onto the rotating table sandwiched between the two pieces of ply and then secure them together with some webbing (or rope) then rotate the table upside down. Undo the webbing/rope and remove the top piece of ply and the slump mold, leaving the slumped clay bowl upside down on the bottom piece of ply. It could then be flipped right ways up again. Other option would be to get another pair of hands to help flip it over onto a board.
  15. Hi Kiki, if nobody here has an electrician they can recommend in your area I would ask at the pottery/ceramic supply places for someone they recommend to people. Somewhere that sells kilns should be able to give you an electrician or two to contact.
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