tbaa Posted November 22, 2016 Report Share Posted November 22, 2016 I was not able to get back on for a while....password problems, but so relieved to see I can again. Last I wrote, May to August, I was muddling through trying to understand my clay body....and why it didnt vitrify. Why the glazes didnt work at all either. Thankfully I am over that hump. It was all poor tutorship: firing not done properly etc. re-testing on my own bore better results for both. But still struggling with glaze colors turning out how they should. Panama red, for example. I got this off CAD I believe. The recipe is recommended for reduction but I got none of the blue speckles, and the red was rather dullish - more a deep rose. I've mixed another batch and increased the copper carb for two tests. One by .25% and the second by .50%. Is this enough? any other ingredient that should be tweaked. (I can provide the recipe of course, but dont want to take up that space unless asked....) All the clear and base glazes have resulted in varying shades of grey. John Britt, who has been kind enough to answer a few questions, says this is likely to be the case on stoneware in reduction. I use a gas fired kiln. Any suggestions on how to fix this problem? Using a white slip over the stoneware clay? I'd also like to use brush work, but as the clay effects these colors as well, would doing brush work over a white slip work? Or would an engobe be better? Any reference for Cone 6 reduction glazes will be very very helpful too. Link to comment Share on other sites More sharing options...
Marcia Selsor Posted November 22, 2016 Report Share Posted November 22, 2016 Yes clear over stoneware is gray. Typical in many Korean pieces. Use a white clay body or white slip as you mention. Adding copper to copper red isn't the answer. It is very dependent of the reaction. Liver color is from the firing. Start a gentle reduction about ^010 up to ^04...then neutral til ^5 starts going then reduction again. Does not need to be belching smoke. It won't climb if it is a completely inefficient flame. Reduce by both tampering down and cutting the air on the burners. If you hold a stick by the upper peep hole and have a gentle licking purple green flame, the stick won't burn for lack of oxygen.That is all the reduction you need.I fired a good Panama Red in Corpus Christi when I taught a ^6 reduction firing workshop there a few years ago. Marcia Link to comment Share on other sites More sharing options...
Mark C. Posted November 22, 2016 Report Share Posted November 22, 2016 Most fire electric oxidation kilns on this site I was told recently so let me say welcome as I to am a gas reduction person myself. You are not firing in my temp range(cone10) but it sounds like a reduction issue. As Marcia said clears all turn grey. This is what stonewares look like with this glazes You can slip your stone ware with white clay or work with white clay white clay will have brighter colors to some degree. Stoneware does earthy browns well.You can also get great matt glazes Porcelain and whites tend to work better with shiny glazes I suggest you test all your glazes on both white and stoneware bodies and work from that point as to what you like. Link to comment Share on other sites More sharing options...
Marcia Selsor Posted November 22, 2016 Report Share Posted November 22, 2016 Here is a copy of my ^6 reduction workshop I taught in Corpus Christi ^6 Reduction workshop.pdf Link to comment Share on other sites More sharing options...
SydneyGee Posted November 22, 2016 Report Share Posted November 22, 2016 Most fire electric oxidation kilns on this site I was told recently so let me say welcome as I to am a gas reduction person myself. You are not firing in my temp range(cone10) but it sounds like a reduction issue. As Marcia said clears all turn grey. This is what stonewares look like with this glazes You can slip your stone ware with white clay or work with white clay white clay will have brighter colors to some degree. Stoneware does earthy browns well.You can also get great matt glazes Porcelain and whites tend to work better with shiny glazes I suggest you test all your glazes on both white and stoneware bodies and work from that point as to what you like. Well that is why I had so many problems with the clear! That should really be taught to the students... no wonder it always looked bad. I had no idea that was because of the reduction! Link to comment Share on other sites More sharing options...
SydneyGee Posted November 22, 2016 Report Share Posted November 22, 2016 Well now at least I know how to get grey if I need it.... Link to comment Share on other sites More sharing options...
bciskepottery Posted November 23, 2016 Report Share Posted November 23, 2016 Many clay manufacturers post pictures of their clay bodies fired in oxidation and reduction so you can see what you are getting and the colors produced in different atmospheres. Here is one example from Highwater for Phoenix: http://www.highwaterclays.com/index.cfm?fuseaction=product.display&product_ID=244&ParentCat=34 Link to comment Share on other sites More sharing options...
Kaolinwasher Posted November 23, 2016 Report Share Posted November 23, 2016 color is subject to many variables. Did you start the reduction at the right time , was the glaze to thick or to thin, and it is certain the body must match the glaze, thats what i found out when doing celadons, its a balancing act on many points, and it may all seem simple but putting all the variables together the right ways is the real challenge. Link to comment Share on other sites More sharing options...
tbaa Posted November 23, 2016 Author Report Share Posted November 23, 2016 Marcia, Mark - thank you! I am so glad to be able to get back on this forum. Marcia your tip for firing is fantastic. I will be absorbing your workshop file for a while! My next step is getting the firing Mark, I will test as you advised, and I am delighted to find others that are using gas / reduction atmosphere Kilns. I happen to live in India, in the mountains at 7,500 ft. I assume this will have some effect on firing. Clay - its what I can get. My location means I have to order this bulk, so I'm stuck with what I have. One cannot go into a store and buy clay anywhere in India, nor are there varieties to choose from, nor is it possible to order on line. My white and earthenware clay is low-fire, and I'll get to that once I've worked out the stoneware! I will have to try the while slip over stoneware. A glazing course I took in New Delhi set me off course for months - and all because of an indifferent and unorganized teacher. Wonderful, enthusiastic potter, BUT....... !! Clay did not vitrify, glazes were nothing like I expected etc etc. it took me months of muddling to work out that it wasnt a problem with my clay, but the incorrect firing. AND The fact the clay has iron, AND other factors such as reduction vs oxidation. Wouldnt you expect a teacher to explain that at the outset????! Mark, Marcia maybe a handbook for reduction potters is a good idea? A Technician from Delhi who helped run my test kiln, was better, but still pretty inept. But enough whining! I am delighted to have found you .... have John Britt's firing charts, Marcia's reduction workshop printed out, and feel I am close to understanding the dynamics of this amazing thing called glazing! Hopefully I will have results in temmuku tea dust, panama red, and more in a few days. Link to comment Share on other sites More sharing options...
Marcia Selsor Posted November 26, 2016 Report Share Posted November 26, 2016 At 7500 feet you need a taller stack / chimney because the draw is weak due to thin air. Burners with blowers solve this problem. Marcia Link to comment Share on other sites More sharing options...
Marcia Selsor Posted November 28, 2016 Report Share Posted November 28, 2016 Do you know Adil Writer in India?or Vinks on this forum? Marcia Link to comment Share on other sites More sharing options...
tbaa Posted November 29, 2016 Author Report Share Posted November 29, 2016 Marcia, no, I dont know either Adil or Vinks. Assuming they're both potters? Thanks for the note on the altitude. I am still getting glazes ready to test....while waiting for a new pressure gauge to arrive. ......and sort of holding my breath. Link to comment Share on other sites More sharing options...
Pieter Mostert Posted November 30, 2016 Report Share Posted November 30, 2016 If you're looking for mid-fire reduction glazes, there are a whole bunch on Glazy. If you're on Facebook, I suggest you join the Ceramic Recipes group. I think they have more people who fire reduction than on the CAD forums. Link to comment Share on other sites More sharing options...
tbaa Posted December 1, 2016 Author Report Share Posted December 1, 2016 Thanks a ton Pieter. Link to comment Share on other sites More sharing options...
Marcia Selsor Posted December 1, 2016 Report Share Posted December 1, 2016 Marcia, no, I dont know either Adil or Vinks. Assuming they're both potters? Thanks for the note on the altitude. I am still getting glazes ready to test....while waiting for a new pressure gauge to arrive. ......and sort of holding my breath. Yes, Vinks is a member of this site. Adil is a friend who was with me at the symposium in Barcelona. He has a big operation some where in India. Marcia Link to comment Share on other sites More sharing options...
tbaa Posted December 3, 2016 Author Report Share Posted December 3, 2016 Oh, will look him up.... Link to comment Share on other sites More sharing options...
Marcia Selsor Posted December 3, 2016 Report Share Posted December 3, 2016 His name is Adil Writer. He does some soda firing there and high fire reduction. Adil Writer Artist Adil Writer is a ceramic artist, painter and architect from Bombay, India, currently living and working in Auroville universal township in south India. He is a partner at Mandala Pottery which produces functional tableware, assorted ceramic items, and architectural ceramic murals and installations. From his own studio at Mandala, he creates his own line of studio pottery. Marcia Link to comment Share on other sites More sharing options...
tbaa Posted December 4, 2016 Author Report Share Posted December 4, 2016 There seems to be a good concentrations of potters in Pondicherry, and I guess particularly Auroville. I should visit there, as there are a couple of other potters whom I've written to about classes etc. I am pretty sure I've heard of Mandala, and I'll look that up. two opposite ends on the map of India. My location, Mussoorie in the north, and Auroville waaaay down in the warm and wonderful south! Marcia, is there a guide to firing a gas kiln that is as clear as your reduction glaze handout? I am going to follow John Britt's R1 chart for my test Kiln, and then again for a glaze firing in the main kiln, but it would be great to find some directions that help with the rate at which the temperature should go up etc. I am going to do another search on the net, but this is just in case you already know..... Its overwhelming really, as one firing doesnt fit all glazes, but I'll start with one and see how it affects the glazes I'm testing. I'd like to get that - the firing part- right though! Link to comment Share on other sites More sharing options...
Marcia Selsor Posted December 5, 2016 Report Share Posted December 5, 2016 I answered this in your other post asking fir firing schedules. marcia Link to comment Share on other sites More sharing options...
tbaa Posted December 5, 2016 Author Report Share Posted December 5, 2016 yes, thanks, I got your message and replied. Link to comment Share on other sites More sharing options...
tbaa Posted December 10, 2016 Author Report Share Posted December 10, 2016 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??? Link to comment Share on other sites More sharing options...
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