docweathers Posted December 28, 2014 Report Share Posted December 28, 2014 I'm fiddling with the idea of doing mocha diffusion over the top of glazes so that they come through sharper. To do this, I need a reliable very high ball clay cone 6 glaze as a starting point for further adjusting it with insight.Aany recommendations would be appreciated Link to comment Share on other sites More sharing options...
High Bridge Pottery Posted December 29, 2014 Report Share Posted December 29, 2014 Could you start with a slip recipe and try adding some stuff? A quick search came up with (slip) : Feldspar - 5 Ball Clay - 75 Kaolin - 10 Silica - 10 Maybe try adding some more feldspar in or a frit/good flux. Link to comment Share on other sites More sharing options...
oldlady Posted December 29, 2014 Report Share Posted December 29, 2014 doc, are you going to put a slip over a glaze or just add color to a glaze and hope it diffuses they way you want? did it not work the way you liked? Link to comment Share on other sites More sharing options...
docweathers Posted December 29, 2014 Author Report Share Posted December 29, 2014 I will try your slip recipe in Insight and see if I can turn it into a glaze, probably with some frit and removing the kaolin. I'm curious where and how you were able to search for a high ball clay glaze/slip. My hope is to come up with a base glaze recipe that I can put over bisque and then do mocha diffusion on it. I'm still experimenting with the mocha diffusion process to get the kind of patterns I want. Most often I'm getting very pretty fine delicate flower like patterns which would be blurred by glaze over them. I'm still working out getting the dendrite affect on a consistent basis. thanks for the help Link to comment Share on other sites More sharing options...
High Bridge Pottery Posted December 29, 2014 Report Share Posted December 29, 2014 I searched 'mocha diffusion pottery' in google and this page came up http://ceramicartsdaily.org/pottery-making-techniques/ceramic-decorating-techniques/mocha-diffusion/ The recipe is there. I would make some little plates and try many combinations of ball clay and stuff with the diffusion. Blends of two things, three things and four things. It will give you a better idea than insight. Flat is good incase something melts badly. I would start with a feldspar and ball clay, some frit and ball clay and a high CaO flux with ball clay. Whatever you have in the glaze cupboard. Link to comment Share on other sites More sharing options...
oldlady Posted December 29, 2014 Report Share Posted December 29, 2014 maybe the covering glaze is at fault. i have several pieces with very thin designs and there are sharp distinctions and edges. Link to comment Share on other sites More sharing options...
docweathers Posted December 29, 2014 Author Report Share Posted December 29, 2014 I guess I can turn hoppers slip into a glaze by dosing it with a bunch of frit. I will run some tests. I will also retest my cover glaze to see if something is screwed up there. Thanks for your suggestions Link to comment Share on other sites More sharing options...
High Bridge Pottery Posted December 30, 2014 Report Share Posted December 30, 2014 Is it all the impurities in the ball clay that make it alkaline? Could be worth trying out something other than a frit so you have some soluble bits. I am thinking any of the alkaline earth metals magnesium, calcium or strontium. Could add to the acidbase reaction. Link to comment Share on other sites More sharing options...
docweathers Posted December 31, 2014 Author Report Share Posted December 31, 2014 that's a good idea worth trying. Link to comment Share on other sites More sharing options...
PeterH Posted January 1, 2015 Report Share Posted January 1, 2015 Am I right in thinking that the glaze is diffusing/blurring the mocha pattern on the bisqued slip? If so, you might consider trying mocha diffusion into slip using stains as colourants. These should resist any solvent effects of the the glaze better than oxides/carbonates. If not, are you sure that you want to mocha onto the top of a glaze, which will melt and encourage movement, rather than onto some sort of self-glazing slip? Regards, Peter I've only tried a few mocha test-pieces, some years ago. I failed to get mocha patters large enough for my decorating ideas and lost interest, but had no problems with glaze-induced blurring -- so it's not inevitable. If you are using iron oxide as colourant you might look at Cardew's iron red (minus the iron) as it is intended not to disolve iron. (Book not at hand, full details if you want them.) Link to comment Share on other sites More sharing options...
docweathers Posted January 1, 2015 Author Report Share Posted January 1, 2015 yes I am wanting to try this on top of tbisque versus greenware. I have some encapsulated stains that should be very resistant to the solvent affect you describe. This whole project may not be a good idea but was is something I'm kind of fiddling with has an interesting possibility. I really haven't made much use of iron oxide as a colorant. I tend to like little brighter colors. thanks for your suggestions Link to comment Share on other sites More sharing options...
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