jrgpots Posted March 30, 2015 Report Share Posted March 30, 2015 Ok, I've been working on getting a cone 6 Nuka glaze. Here is what I have: Rice hull ash. 31.2 Hardwood ash (walnut). 31.2 Custard feldspar. 23.1 Frit 3124. 12.0 Bentonite. 2.5 Can someone with Insight run this formula and see if I'm even in the ballpark for cone 6? I have a lot of melt failures so far at this cone. Please help Jed Link to comment Share on other sites More sharing options...
Guest JBaymore Posted March 30, 2015 Report Share Posted March 30, 2015 Where are you getting your rice husk ash? best, .......................john Link to comment Share on other sites More sharing options...
Min Posted March 30, 2015 Report Share Posted March 30, 2015 Okay, I'll take a stab at this but with a huge caveat or 3. I used the rice hull analysis from Insight and entered that into the materials data table plus I couldn't find a walnut ash analysis so I used the Insight one for hardwood ash. Either way ash analysis is going to be iffy to say the least. If you have a target formula you are aiming for I can fiddle the recipe to what you are looking for. I know diddly doops about Nuka glazes so I'm only going by the chemisty. Silica and alumina are both really low, do you have a ^6 Nuku recipe to compare yours with? (I included the bentonite in the formula) Rice hull ash 31.22 Hardwood Ash 31.20 Custer Feldspar 23.10 Ferro Frit 3124 12.00 Bentonite 2.50 100.02 CaO 0.31* MgO 0.25* K2O 0.28* Na2O 0.07* P2O5 0.07* TiO2 0.00 Al2O3 0.12 B2O3 0.05 SiO2 1.79 Fe2O3 0.00 FeO 0.00 MnO 0.02 Calculated LOI: 2.41 Imposed LOI: Si:Al: 15.56 SiB:Al: 15.97 Thermal Expansion: 9.31 Formula Weight: 193.17 Hope this is of some help and not just a bunch of gibberish. Madeleine Link to comment Share on other sites More sharing options...
jrgpots Posted March 30, 2015 Author Report Share Posted March 30, 2015 Where are you getting your rice husk ash? best, .......................john A friend in Ausrtalia traded me some tumble weed ash for rice husk ash. I don't have a lot so I feel that every time I try, I'm wasting precious material. Jed Okay, I'll take a stab at this but with a huge caveat or 3. I used the rice hull analysis from Insight and entered that into the materials data table plus I couldn't find a walnut ash analysis so I used the Insight one for hardwood ash. Either way ash analysis is going to be iffy to say the least. If you have a target formula you are aiming for I can fiddle the recipe to what you are looking for. I know diddly doops about Nuka glazes so I'm only going by the chemisty. Silica and alumina are both really low, do you have a ^6 Nuku recipe to compare yours with? (I included the bentonite in the formula) Rice hull ash 31.22 Hardwood Ash 31.20 Custer Feldspar 23.10 Ferro Frit 3124 12.00 Bentonite 2.50 100.02 CaO 0.31* MgO 0.25* K2O 0.28* Na2O 0.07* P2O5 0.07* TiO2 0.00 Al2O3 0.12 B2O3 0.05 SiO2 1.79 Fe2O3 0.00 FeO 0.00 MnO 0.02 Calculated LOI: 2.41 Imposed LOI: Si:Al: 15.56 SiB:Al: 15.97 Thermal Expansion: 9.31 Formula Weight: 193.17 Hope this is of some help and not just a bunch of gibberish. Madeleine Link to comment Share on other sites More sharing options...
Guest JBaymore Posted March 30, 2015 Report Share Posted March 30, 2015 Jed, Thanks. Was hoping you had a domestic source. The domestic stuff I've found (difficult) is not burned correctly. I import mine too at the moment.................. my true one is a VERY expensive glaze to make. Reserved basically for Chawan and other high ticket items. I have a "fake" nuka also....that gets used for most other stuff. My glazes are cone 10. Al/Si ratio is 1:18. Point 7+ calcium. Undersupplied with Si and AL also. That is typical of nukas. best, .......................john Link to comment Share on other sites More sharing options...
jrgpots Posted March 30, 2015 Author Report Share Posted March 30, 2015 Like I said precious material.... Min, I was hoping that the ferro 3124 would boost the Aluminun and lower the melting point. I may be way too low on the amount of the frit, because I have not achieved a good melt yet. Adding more 3124 should add Al and drop the melting point. Jed Link to comment Share on other sites More sharing options...
Tyler Miller Posted March 30, 2015 Report Share Posted March 30, 2015 It might be cheaper just to get rice hulls from a farm supply store and burn them. They're used as chicken bedding in much of the US. Far greater control over how they're burned, too. Link to comment Share on other sites More sharing options...
bciskepottery Posted March 30, 2015 Report Share Posted March 30, 2015 John Britt's new book on Mid-fire Glazes has 3 recipes for Nuka glazes. (page 156/157). He states he used a boron frit to lower temperature from cone 10 to cone 6 for a better melt (Frit 3134). Link to comment Share on other sites More sharing options...
Guest JBaymore Posted March 31, 2015 Report Share Posted March 31, 2015 It might be cheaper just to get rice hulls from a farm supply store and burn them. They're used as chicken bedding in much of the US. Far greater control over how they're burned, too. Thanks Tyler. I've thought of that in passing ....... but adding yet another "labor factor" into what I do with the already crazy wood firing aspect is not all that appealing. Particularly as I get older . And I imagine that it'd take me a good while of failures to learn to burn them correctly to get the black ash. best, .....................john Link to comment Share on other sites More sharing options...
Chantay Posted March 31, 2015 Report Share Posted March 31, 2015 I happen to know a rice farmer. Maybe I should look into this. You only want the husk? Link to comment Share on other sites More sharing options...
Guest JBaymore Posted March 31, 2015 Report Share Posted March 31, 2015 I happen to know a rice farmer. Maybe I should look into this. You only want the husk? Thanks for the offer..... however what I need is the partially burned ash of the husks. If they are burning the husks in piles in the open (unlikely in the US) then I'd LOVE to talk to them. Also...... I would like a good supply of dried rice straw also. That would also really interest me. Maybe they could pack it in a big box now and then and ship it. best, ........................john Link to comment Share on other sites More sharing options...
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