jrgpots Posted September 20, 2013 Report Share Posted September 20, 2013 I made the following glaze: Scoria dust (40 mesh) 37.5 Hardwood ash (unwashed) 37.5 Silica 15.0 Ball clay 7.3 Bentonite 2.7 Applied to Laguna Electric brown clay. Fired to cone 5 oxidation. Probably underfired, but I like the "natural rustic" appearance. I applied it to a Native American flute. I thought its rough texture matched the piece. I will be doing line testing at cones 6 and 7 to see if I can get a better melt. Does anyone think this has potential? Jed Link to comment Share on other sites More sharing options...
Biglou13 Posted September 20, 2013 Report Share Posted September 20, 2013 I like it. A lot. The earth tones and texture compliment the form Congrats on first glaze. Looking at recipe I'm (newB to chemistry) first thought is...no flux? Eg feldspar,nepsy. But then that risks taking away some of texture, and probably making glaze more glossy. I need to do research as to role of scoria dust. Another part of me says leave it alone Link to comment Share on other sites More sharing options...
jrgpots Posted September 20, 2013 Author Report Share Posted September 20, 2013 I think the scoria has a lot of Na, K, and feldspar. Basalt which is scoria if allowed to cool slowly under pressure becomes granite (feldspar, quarts, and mica.) The scoria i used came from a low-silica, alkali lava. On to the line testing. Link to comment Share on other sites More sharing options...
Min Posted September 20, 2013 Report Share Posted September 20, 2013 I think the scoria has a lot of Na, K, and feldspar. Basalt which is scoria if allowed to cool slowly under pressure becomes granite (feldspar, quarts, and mica.) The scoria i used came from a low-silica, alkali lava. On to the line testing. Is scoria the same as pumice? Would that be where the yellow colour is coming from? The hardwood ash will be supplying fluxes also, calcium, magnesium, potassium and phosphorus. Link to comment Share on other sites More sharing options...
jrgpots Posted September 20, 2013 Author Report Share Posted September 20, 2013 Yes, pumice is foamy scoria. Pumice will have a little less iron oxide. Otherwise it is about the same. I added the ash to increase the flux. I will be adding more ash to lower melting point to my next line test. Jed Link to comment Share on other sites More sharing options...
Min Posted September 20, 2013 Report Share Posted September 20, 2013 Yes, pumice is foamy scoria. Pumice will have a little less iron oxide. Otherwise it is about the same. I added the ash to increase the flux. I will be adding more ash to lower melting point to my next line test. Jed Thanks Jed, I learned something today: ) (I added the bit about the fluxes in wood ash for Lou, I realize you would have added the ash for that reason) It looks like a promising glaze that will work well on your flutes. Link to comment Share on other sites More sharing options...
Bob Coyle Posted September 20, 2013 Report Share Posted September 20, 2013 I believe your glaze fluxed just fine, otherwise it wouldn't be so shiny. Maybe you should hold off adding more ash. Test it for sure because it might get runny. Very nice surface effect. Link to comment Share on other sites More sharing options...
Biglou13 Posted September 21, 2013 Report Share Posted September 21, 2013 Thanks guys , learned something new also. I ve added ash to glazed pots and ended up wit a dry mess, was told to add some flux to ashes. Tell us how you are doing line tests. I'm assuming its cone 6-7 ox electric? Link to comment Share on other sites More sharing options...
jrgpots Posted September 21, 2013 Author Report Share Posted September 21, 2013 ...Tell us how you are doing line tests. I'm assuming its cone 6-7 ox electric? I'm going to try a triaxial blend changing the scoria from 30 to 50, the ash from 30 - 50, and the silica from 5 - 15 (each measured in grams). I will keep the clays unchanged. I will test at cones 5 and 7. That means 42 test tiles.....Yuk. Once I find the best blend, I will use that as a base glaze and consider adding colorants too. The triaxial blend graph is below. This is my first attempt at a triaxial blend, so I will gladly accept any advise. Jed Link to comment Share on other sites More sharing options...
Min Posted September 21, 2013 Report Share Posted September 21, 2013 I'm not quite following your triaxial grid. If the peak of the triangle is 100% glaze A, the lower left point is 100%glaze B and the lower right is 100%glaze C then the 1st glaze in the 2nd to top row will be glaze 2 and would be a mix of 80%A with 20%B and 0%C. Glaze number 3, next to glaze 2, would be 80% glaze A, 0%B and 20%C. And so on down the pyramid. I think perhaps you have too many variables. Link to comment Share on other sites More sharing options...
jrgpots Posted September 21, 2013 Author Report Share Posted September 21, 2013 I don't want to go from 0 to 100 on each axis. Instead I want to narrow the range from 30 to 50 on two of the ingredients. The silica I want to test the range from 5 to 15. All I have done is narrow the range of each ingredient. For example, I know I do not need more than 15% silica and no less than 5%, so I narrowed its range. Likewise the test glaze which I have has equal parts scoria and ash. I don't need to test a wider range than +or- 20%. I realize that is not a normal triaxial test. All I did was narrow the range of the variables. Link to comment Share on other sites More sharing options...
Min Posted September 21, 2013 Report Share Posted September 21, 2013 Sorry if I inferred 100 on each side of the triangle. I was talking about a 21 mix test from 3 glazes, A, B and C points on the triangle. I have only done triaxials with changes in the base glaze of 1 material in each of the 3 triangle points. Colorant, flux, silica, whatever you are testing for. From you diagram it looks like stacked line blend tests. I guess I don't understand how you are taking your 3 glazes from the points of the triangle and combining them. All the best with your tests. Min Link to comment Share on other sites More sharing options...
jrgpots Posted September 22, 2013 Author Report Share Posted September 22, 2013 Sorry if I inferred 100 on each side of the triangle. I was talking about a 21 mix test from 3 glazes, A, B and C points on the triangle. I have only done triaxials with changes in the base glaze of 1 material in each of the 3 triangle points. Colorant, flux, silica, whatever you are testing for. From you diagram it looks like stacked line blend tests. I guess I don't understand how you are taking your 3 glazes from the points of the triangle and combining them. All the best with your tests. Min Min, you are so right. I misused the term "Traxial blend.". I was trying to adjust three parts of one glaze, not blending 3 glazes. I was wrong in my terms and caused confusion. I don't have specific analysis of scoria, so I guessed how much ash, scoria, and silica I need to get to unity. I'll see if my stacked line tests work. Thank you for your insight and I apologize for my arrogance. Jed Link to comment Share on other sites More sharing options...
Min Posted September 22, 2013 Report Share Posted September 22, 2013 Sorry if I inferred 100 on each side of the triangle. I was talking about a 21 mix test from 3 glazes, A, B and C points on the triangle. I have only done triaxials with changes in the base glaze of 1 material in each of the 3 triangle points. Colorant, flux, silica, whatever you are testing for. From you diagram it looks like stacked line blend tests. I guess I don't understand how you are taking your 3 glazes from the points of the triangle and combining them. All the best with your tests. Min Min, you are so right. I misused the term "Traxial blend.". I was trying to adjust three parts of one glaze, not blending 3 glazes. I was wrong in my terms and caused confusion. I don't have specific analysis of scoria, so I guessed how much ash, scoria, and silica I need to get to unity. I'll see if my stacked line tests work. Thank you for your insight and I apologize for my arrogance. Jed No worries, nothing to apologize for. Min Link to comment Share on other sites More sharing options...
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