![pottery bubble crackle glaze effect pottery bubble crackle glaze effect](https://i.pinimg.com/originals/e8/af/b4/e8afb404edb11815796ddc3813ca2b08.png)
Japanese Antique Pottery Square Plate Ogata Kenzan Signed Rectangular Dish Pcp93This Is An Authentic Ogata Kenzan Piece That Almost Never Appears On The Market. Vintage Mexican Large Sterling Silver 3 Serving Dishes, Stackable Plates Signed. I still have one of those pots as a reminder.Signed Dish Information Old Porcelain Dish Signed Opaque 19 CenturyMaterial Porcelain. I think a lot of small-time potters like me thought it was our fault! They'll want to know the batch numbers.Does anyone else remember the huge batch of Laguna BMix that bloated? I had a half ton, but some big schools had much more.Ī mention to the clay supplier is not out of line. If the kiln is not over firing, call your clay supplier and let them know what's going on. Also try a couple of pots with another glaze to see if it still happens. If you've still got the boxes that the clay came in, check to see if they're all from the same batch. However if it was truly over firing enough to cause bloating, I would expect your glaze would also show some extra fluidity, which you haven't mentioned. In my experience, digital kilns tend to under fire as the thermocouple ages, not over fire, but it's definitely a possibility. Use some cones to rule out the over firing possibility, though. Could also be a bad batch of clay, which is what I'm betting on. You can see that there a very small, smooth bumps that haven't come through to the surface quite yet, as well as the big bumps. Those look like bloats to me, which are bubbles in the clay, usually due to over firing. They are well worth the extra cost, because it lets you know right away about any future problems that might occur. I had to adjust my cone offsets, but then I started using my own programming schedules and I ended up adjusting my TCs instead of the cone offset. Then each load started getting darker and darker, I put in some cones and my cone 6 firing preprogrammed was firing to cone 7+. I was glazing away fine to cone 6 every time. As your Thermocouples(TCs) and elements get used they can change in the way they heat and read heat. Don't think that just because its digital doesn't mean it can't overfire. My bet is still that your kiln is probably reaching cone 7 and your glaze is blistering/bloating.
![pottery bubble crackle glaze effect pottery bubble crackle glaze effect](https://i.pinimg.com/originals/6c/61/4c/6c614ce1f205d76bdbba331643705694.jpg)
Since you are in a hurry and getting behind the quick thing would be to buy a set of 567 self supporting cones at your supplier, glaze a few pots with different thicknesses (mark them in some way so you will know, Red Iron Oxide w/ water works fine), then compare just in case it is a thickness thing. Also another way to check for this without cones is to fire a pot without glaze in the same load and see if the actual clay body bloats without glaze, however this wont tell you if the glaze is getting too hot or not. That being said when these problems pop up you should put in some cones to see if its a kiln overfiring issue or a glaze issue. If you have always bisque to cone 06, then I don't think that's probably the issue unless this is a new clay batch from your supplier. My glaze recipe is: 25% epk, 25% silica, 10% wollastonite, 25% frit 3134, 15% feldspar minspar.īeing that it is a white stoneware, a bisque to cone 06 is probably fine. The kiln sometimes runs a little on the hot side, but I haven't found that to cause this particular problem before. I fire my bisque to cone 06, and the glaze to cone 6. Should I try re-firing the pieces and doing something differently, like holding it a bit? Please help! I'm getting so delayed on my orders because I keep having to re-make everything and I'm freaking out! The only other thing I can think of that might be different is that it's more humid in the studio because it's the middle of summer. I thought my glaze might have been contaminated so I mixed a whole new batch but the same thing happened. Please see the attached photo- this is what all my pieces came out like. The clay is white and the glaze is clear, but the bubbles that are appearing are white (so it looks like the glaze has fused to the clay body and pulled it out into bumps/bubbles. The last two times I've glaze-fired, TONS of little bumps appeared, a few of them up to a cm wide (those ones looks a little more like an air bubble in the clay. I hand-mix a transparent glaze, which I've used for the last year continuously with great success.