Denise V Brown Posted June 24, 2015 Report Share Posted June 24, 2015 Hi I live in Australia and so the cost of Cornish Stone is high. I'm in the process of making glazes that require Cornish Stone in the recipe, can anyone suggest a substitute? Link to comment Share on other sites More sharing options...
Min Posted June 24, 2015 Report Share Posted June 24, 2015 Dolomite.................... 0.37Custer Feldspar............. 30.43Wollastonite................ 3.30Kaolin...................... 12.85Silica...................... 29.29Nepheline Syenite........... 23.75=========100.00 recipe from here: http://digitalfire.com/4sight/education/substituting_cornwall_stone_194.html Link to comment Share on other sites More sharing options...
High Bridge Pottery Posted June 25, 2015 Report Share Posted June 25, 2015 Cornish stone is about double the price of soda/potash feldspar here in the UK. How does that translate over too Aus? Link to comment Share on other sites More sharing options...
TJR Posted June 26, 2015 Report Share Posted June 26, 2015 Cornish Stone, or Cornwall Stone is a potash feldspar. You could substitute Custer or any other potash feldspar. It is a bit more refractory than Custer, so you will have to test. TJR. Link to comment Share on other sites More sharing options...
Mark C. Posted June 27, 2015 Report Share Posted June 27, 2015 Glaze materials really are cheap no matter what they cost if you think about it.Especially feldspars. At least that what I have found. Mark Link to comment Share on other sites More sharing options...
Bob Coyle Posted June 28, 2015 Report Share Posted June 28, 2015 Glaze materials really are cheap no matter what they cost if you think about it.Especially feldspars. At least that what I have found. Mark Mark is correct. Just remember that any feldspar you use as a glaze component is a complex mix that might work as well or better with a combination of other (cheaper) materials of approx the same chemical composition. the ONLY way you can find out is by testing and tweaking. Cornish stone does not have any wonderful, inherent properties that would be impossible to get otherwise. Software calculations MAY get you closer, but you probably will have to fine tune to get just the results you want. This means understanding how to move the gaze in the direction you want by manipulating the components. There is plenty of info out there and as a newbie it is greatly to your advantage to learn at lest the basics of glaze formulation. Start out with Min's formulation from Digifire and go for it. Link to comment Share on other sites More sharing options...
Denise V Brown Posted June 28, 2015 Author Report Share Posted June 28, 2015 We're looking at $40 a Kg for Cornish stone in Oz. Yes absolutely, i'm going to be experimenting but because of the price I was quoted I thought I'd better find out if it had some particular makeup that was irreplaceable first. Thanks Min for the recipe. Link to comment Share on other sites More sharing options...
curt Posted July 4, 2015 Report Share Posted July 4, 2015 Yep $40 a kilo sounds expensive to me. The problem with trying to artificially replicate it, is that you are introducing all the variation and trace contaminants of 6 new ingredients when all you wanted was the one! Better in my mind to go back to the recipe which uses Cornish Stone, and try to find an approximate single substitute for it that you can get consistently for a reasonable price. There are all sorts of ingredients that folks in Oz cannot really get. Getting completely fed up with constantly trying to "domesticate" imported glaze recipes was one of the best things that ever happened to me. Because that was when I when back to basics and started to make my own! Link to comment Share on other sites More sharing options...
High Bridge Pottery Posted July 6, 2015 Report Share Posted July 6, 2015 That is a bit pricey, cost £1.40 per kg in the uk which seems expensive when all other feldspars are under £0.80 per kg. Link to comment Share on other sites More sharing options...
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