oldlady Posted August 12, 2016 Report Share Posted August 12, 2016 the question is...................... since rutile is an impure form of titanium dioxide and i have both, will my recipe benefit by my using the titanium dioxide instead of the rutile? have been influenced by ray aldrige and his lovely titanium glazes. SAPPHIRE BLUE cone 6 silica 15 EPK (kaolin) 25.5 custer feldspar 25.5 ferro frit 3134 (boron) 42.6 (i know it does not add up to 100) add bentonite 2 rutile 4.3 cobalt oxide 2.1 i have the cobalt oxide this time around. last batch i used cobalt carbonate and increased the amount. the batch is finished but waiting for an answer before i add either rutile or titanium. Link to comment Share on other sites More sharing options...
Pres Posted August 13, 2016 Report Share Posted August 13, 2016 I have found that the use of rutile gives the surface a little more depth and mottling. This especially after a slow cool down. I have some glazes that all for the TiO, but they are not as interesting to me as the rutile glazes. . . personal opinion. Is there some crawling on the edges of your test tiles? The one with the cobalt added seems to have more of it? best, Pres Link to comment Share on other sites More sharing options...
Marcia Selsor Posted August 13, 2016 Report Share Posted August 13, 2016 I think the rutile impurities of iron contribute to the color of the sapphire blue. But I think it is worth doing a test with the titanium alone. You may get a different sort of depth in the glaze. Marcia Link to comment Share on other sites More sharing options...
oldlady Posted August 13, 2016 Author Report Share Posted August 13, 2016 thanks,pres, there is no crawling, the yellowish edges and the big yellowish spot on the second sample are a reflection from my light. i am not much of a photographer. Link to comment Share on other sites More sharing options...
glazenerd Posted August 13, 2016 Report Share Posted August 13, 2016 I have noticed color shifts in my crystalline glaze with as little as 2% rutile and 4% titanium Nerd Link to comment Share on other sites More sharing options...
oldlady Posted August 13, 2016 Author Report Share Posted August 13, 2016 thanks, all of you. OK! looked at a lot of tests from several years with sapphire over other colors etc, and i will go with the original recipe. cobalt oxide and rutile. did 8 tests of the new color alone and with the white stuff that is just base glaze, some matte some not. loaded kiln totally to the top. now to wait until the extreme heat dies back a little so i am not running the AC and kiln at the wrong times. Link to comment Share on other sites More sharing options...
Denice Posted August 13, 2016 Report Share Posted August 13, 2016 I did the same thing last week and got lucky, I had the kiln ready to go and a cold rainy front moved in and I got to fire my kiln. Denice Link to comment Share on other sites More sharing options...
Babs Posted August 14, 2016 Report Share Posted August 14, 2016 That is a serious amount of Cobalt oxide! Nice glaze, good luck with the firing. Link to comment Share on other sites More sharing options...
oldlady Posted August 14, 2016 Author Report Share Posted August 14, 2016 yes, babs, it does seem like a lot but look at the gorgeous color! you may not know about Midnight Blue a very old recipe i have from the 70s. i won't use it anymore because it spits cobalt out and onto things like the elements and shelves. have several "halo" circles from midnight blue. never had any problem with this Sapphire. and i think it helps to put blues on shelves that do not have elements near them. temperature is at about 2158 F right now, heading for cone 6 which the book from L&L kilns says is 2199 F when using the slow glaze program. i put an 11 minute hold on it so it should go off soonish. (too much math at this time of night) denice, i gave up and put the AC temp near 80 and turned on the kiln this AM. turns out the weather forecasters talk about DC and its heat but only mention the counties surrounding the city. i am just outside the normal area of the forecast where it is just a tiny bit less blisteringly hot. Link to comment Share on other sites More sharing options...
Celia UK Posted August 14, 2016 Report Share Posted August 14, 2016 When you used cobalt carbonate Old Lady, how much did you use in this recipe? I only have the carbonate. Link to comment Share on other sites More sharing options...
oldlady Posted August 14, 2016 Author Report Share Posted August 14, 2016 celia, good thing you have the carbonate. the test that i showed is one made with carbonate. the new batch came out more like the second test shown. i originally made 2172 grams in a small bucket and the cobalt oxide would have been 42 (i think) and someone on the forum told me to add 20 more grams if using cobalt carbonate. so i did. hope this math is right, it is what i used for my recipe except i used the da$% oxide and don't like it as much. Link to comment Share on other sites More sharing options...
Babs Posted August 15, 2016 Report Share Posted August 15, 2016 So now I'm confused. The test tile on left has cob.carb only 4.1%? Or 2.1% cob.oxide and 1% cob. Carb? Late here brain slower Or just cob.carb 2.1% Link to comment Share on other sites More sharing options...
Babs Posted August 15, 2016 Report Share Posted August 15, 2016 Or cobalt carb only 3.1% think that's what you did? Link to comment Share on other sites More sharing options...
Marcia Selsor Posted August 15, 2016 Report Share Posted August 15, 2016 Old Lady and Celia, This is a previous discussion of the forum. When substituting cobalt carbonate for cobalt oxide use 1.53% Cobalt carbonate for 1% cobalt oxide So it is more like 1/3 or 33% rather than 20 % Marcia Link to comment Share on other sites More sharing options...
Celia UK Posted August 15, 2016 Report Share Posted August 15, 2016 Old Lady and Celia, This is a previous discussion of the forum. use 1.53% Cobalt carbonate for 1% cobalt oxide So it is more like 1/3 or 33% rather than 20 % Marcia Now you've really got me confused Marcia. Old Lady's original post has 2.1 (%) cobalt oxide although the quantities she subsequently recalled - 2172g batch with 42g cobalt oxide is actually 1.9%. (42/2172 X 100) The additional 20g because carbonate is weaker makes it 2.85%. so I'm not sure where your 20% & 33% come from?? Link to comment Share on other sites More sharing options...
oldlady Posted August 15, 2016 Author Report Share Posted August 15, 2016 celia, this is a picture of my glaze book page. the original recipe called for cobalt oxide. i did not have any. i used cobalt carbonate. the test 103 shows the result of my first attempt, granted the sample is too thin. i added the 20 more grams of cobalt carb and the result is test 113, the one in the picture when i posted this on august 12, last week. i just found my original notes re this attempt and see what happened. if you can read my handwriting. the second picture, with the large cat dish was done after another batch was made with cobalt carbonate. that is what i usually got when using sapphire. this week's test with copper oxide is shown below. i do not like it as much as the carbonate. tested it over 4 of my white or no color base glazes and they came out simply blue. disappointing. because i cannot move the pictures i posted, they may be out of order. start reading notes part way down where Hesselberth starts the line. read the second page down to Mixed............. this is just exactly why people ought to keep better notes when testing. obviously, i did not. Link to comment Share on other sites More sharing options...
Celia UK Posted August 15, 2016 Report Share Posted August 15, 2016 Thanks Old Lady - I've certainly got something to start with! I agree that 113 is better than 103. Link to comment Share on other sites More sharing options...
Babs Posted August 15, 2016 Report Share Posted August 15, 2016 Yes so when you made up your recipe , multiplying the original amount by 20, you got from 2.1% to 42grams, then you added 20 more grams taking the addition of cobalt carb. to 62, dividing back down again by 20 it comes to 3.1%. Celia as Old Lady broke the rules and did not convert the amounts of the recipe to percentages, note her first quantity of the glaze was 2174gms which is 20 x 108.7. SO if you are going to test with cob. carb I'd start with 3.1gm, not as a percentage but as a weight in accordance with the other chemicals. with OL's method. If it works do it. Link to comment Share on other sites More sharing options...
Celia UK Posted August 16, 2016 Report Share Posted August 16, 2016 I'm with you Babs! I used slightly different Maths and got to 3.2g in a 100g sample. Link to comment Share on other sites More sharing options...
oldlady Posted August 16, 2016 Author Report Share Posted August 16, 2016 once you folks work it out, please send me the revised recipe so i can do it again. i will throw out the old page and replace it with a nice, neat one. Link to comment Share on other sites More sharing options...
Marcia Selsor Posted August 16, 2016 Report Share Posted August 16, 2016 Old Lady and Celia, This is a previous discussion of the forum. use 1.53% Cobalt carbonate for 1% cobalt oxide So it is more like 1/3 or 33% rather than 20 % Marcia Now you've really got me confused Marcia. Old Lady's original post has 2.1 (%) cobalt oxide although the quantities she subsequently recalled - 2172g batch with 42g cobalt oxide is actually 1.9%. (42/2172 X 100) The additional 20g because carbonate is weaker makes it 2.85%. so I'm not sure where your 20% & 33% come from?? This was in response to substituting 1 percent of Cobale oxide you need 1.53 % Cobalt carb. So sorry for any confusion. We just drove back from Montana 1860 mile road trip. Head is a little goo goo brained. Marcia Link to comment Share on other sites More sharing options...
Babs Posted August 16, 2016 Report Share Posted August 16, 2016 I was going on what OL actually used So if converting to % would have to apply toadditions too Link to comment Share on other sites More sharing options...
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