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tbaa

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  1. oh fantastic! thanks so much.
  2. How long can glazed pieces be left before firing? days? months? I have some pieces I've glazed but as I am travelling, it may be a month before I can fire them. Also, as I do underglaze decoration and sgraffito I'd like to get some pieces ready, and simply have them ready to dip them in clear glaze before firing. Are the colors likely to be affected? I just read some amazing advice on how to use hairspray or spray-on starch to prevent smudging of underglazes, oxides etc. Can I then dip these items (protected with starch or hairspray) into my clear glaze would the hairspray / starch contaminate the glaze?? This seems like a 'no-brainer' as the oxides DO contaminate the glaze....and the hairspray / starch simply burns away in the firing....but as it seems too good to be true, I simply have to check. Despite a lot of advice from people like Marcia Selsor, glazenerd and others, I am still trying to make glazes that work. This involves a few days of getting things ready for the kiln. As I develop glazes that work, I'd like to have some things ready to fire, while I mix and test new recipes and combinations. Hence the question about how long glazed pieces can sit around before being fired. as always - many thanks in advance!
  3. thanks Min. this seems the way with ceramics!!! I am still working on getting ^6 glazes I like, so unlikely I will ruin any while experimenting. Thanks for the suggestion for heating the pots.
  4. Some of my cone 6 glazes have had poor results. I'd like to experiment by re-firing these pieces, using a low-fire glaze. Is this possible? And lustre glazes? what would work best over cone 6 glazes ? Any suggestions and guidance will be hugely appreciated!
  5. Teaching Ceramics to Adults

    I came here looking for possible instructors, but this is just to share my thoughts on why I think teaching skills are important. Good instruction takes away a lot of the uncertainty when you're learning. Many clay/pottery classes are very 'try your hand at throwing' ..... you'll get the hang of it. Easier said than done. Four years ago I committed to pottery and set up a studio at home. the clay was the first challenge. My experience with an instructor a few years ago, made a huge difference to my centering and throwing skills. Marc Mancuso, who I took some one on one classes with in Boston, was extremely helpful in explaining what needs to done to that lump of clay, where to apply pressure etc. I dont wrestle with the clay anymore. Then I got a lot of input about clay bodies etc here on CAD. Also very carefully considered and well articulated. Clay body issues resolved. My experience with a glazing workshop in India was dismal. I learned nothing - not about materials, not about how some of these interact, and nothing about firing. Marc was great with glazes as well, but the materials and conditions and fuel are all different here. I have books, I've been on line and gotten a lot of advice. From some very experienced people. All helpful, but the materials and conditions remained a problem. I finally found a ceramicist who is knowledgeable about the materials and their chemistry, and helped me develop my first base glazes. Explained some of the nuances of firing, and helped me test a batch of glazes. I have learnt a lot, and though I have yet to fire these new glazes, I am prepared to do it with more confidence. The biggest problem turned out to be one of the feldspars - I recently tried to set up a small course for beginner potters at my home in the Himalayas, and had to call it off. The instructor I found is a very talented ceramicist, but unorganized, and without any "lesson plan". I know pottery cant be a rigidly timed or instructed class, but yes, strong teaching skills are a good thing!
  6. Two firings and I am making progress, albeit slowly. While I am testing various base glazes, I found that Nelson's base from Marcia Selsor's handout works well. I tried all four colors as well, and Chcolate worked the best. A couple of questions: Black and granite were nearly the same. I will try the granite with less Iron Oxide. Black had some olive flecks, and granite was a darker version. I used iron oxide black in both recipes - should it have been red? While the flow/melt was good on all others, the teal came out dry. Any idea why that would happen??? Lastly, If I mix a large batch of the base, is it possible for me to mix colorants into smaller batches of the ready base glaze? I have a dry total of 100grams. add 80 - 100 grams of water, getting a total of 180-110. Any way I can add colorants to say every 180g of this? Too good to be possible???
  7. two firings, and its not as difficult as I thought it would be! Still, a LONG way to go, but the above advice helped. Thanks!
  8. O.K.! Well, enough wondering what to do I guess. will start with firing first thing tomorrow morning. Thank you all for your help, AND patience.
  9. My test tiles. Square ones fired in A Delhi studio where I went for a glaze course. The smaller ones below, fired in my test kiln. Clay from my own batch in both instances. Turquoise glaze is the lakeside studio recipe, mixed at the Delhi studio. two very different results. So thats what I'd like to keep working on - the firing schedule, and will see what the kiln's quirks are over time.
  10. John, Oh boy, your post shows now.... anyhow, .....
  11. J Baymore - i saw your note about primitive pottery, though it doesnt show here. Sent a reply but some glitch with checking if I was a robot or not.... Long reply with picture posted....but no idea where it went. Holey moley! So, here I go again: Thanks, I will look for the book. I am now trying to work out firing schedules. Mainly at what rate to increase temperature in my kiln. How many degrees over how much time - from whatever the loaded kiln reads at before I light it.
  12. yes, thanks, I got your message and replied.
  13. Thanks Marcia. I will indeed keep trying until I get familiar with the kilns. Linda Mosley's chart is a good start for me to understand how many degrees per hour - which is the part I wasnt able to find anywhere. Especially with regard to the first Hour or two. Still not sure though, as The time for the initial temperature stage seems long to me, so I'm hoping to get more pointers, as clearly, I have an awful lot to learn..... Oh, also, not sure why the chart came out the way it did, and here is clearer version for anyone who was wondering: TEMP RANGE RATE of F per HOUR # OF HOURS 70-400 50-80 4-6 (? surely not??) 400-1200 150 5 1/2 1200-1900 200 4 Total heating time 12-18 hours Total cooling time 12-18 hours
  14. Found this site, which is very clear and articulate - and may be helpful for others who need the basics as I do: Linda Mosley. lmosley.com. The firing chart below. I will explore further, as I'm not sure if I understand the 12-18 hour part... Temperature Range Rate of °F. per Hour Number of Hours 70 – 400°F 50 – 80 4 – 6 400 – 1200 °F 150 5 1/2 1200 – 1900°F 200 4 Total Heating Time 12 – 18 hours Total Cooling Time 12 – 18 hours
  15. My ignorance is probably getting old, but here is another question from me: What increments in temperature are best when starting to fire. I am dubious about the expertise I've received, and it is as below: My test kiln has been fired once by a technician who came up from the company, and heres what he did: Fired the kiln at 10:13 am. At 10:35 (22 minutes) the temp was up from mid 70s to 335C. 11:15 - 850C 12:45 - 991 1:05 - 1043 1:55 - 1152C 2:20 - 1192 2:25 - 1200C 2:40 - 1223C 2:49 - 1225C 2:50- 3:03 Kept temp stable : 1225-1222. Roughly 14 min. Turned off at 3:03 Temperature at 5:55 was down to 683C From whatever I have read, this was not correct, but the tech was adamant. But, I'd like to correct it, and understand the speed at which the temperature should rise. Some approximation at least. Test Kiln results will differ from the main one. Understood. But the above process didnt seem to start as a 'gentle' one. Even though I understand that the small kiln will reach cone 6 quicker, any suggestions on how to gauge this? Marcia Selsor's advice and John Britt's Charts help a lot, but it would be great if there was some reference for how much time it should take to go from whatever temp the loaded kiln is - 70s, 80s - to getting to the first stage of firing. Just that basic start. When I used the big kiln, we took an hour to simply let the interior 'dry', and then one hour to get to 240C. Then in we lit the second burner, and in twenty minutes we were up from 240 to 463 degrees. Too fast? or OK? That was a bisque firing, but even then, the same tech didnt follow any logical temperature increments. I hope the above makes sense.....?
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