AWPottery Posted March 28, 2014 Report Share Posted March 28, 2014 I have a cone 10 reduction glaze recipe called June Perry's #1591 Color A... Recipe is as follows: Ferro Frit 3271- 13g (they stated you can use other frits like 3191, 3278) Kingman Feldspar- 44g Whiting- 14g Monarch Kaoilin- 3 Silica- 26 Add: Copper Carb.- .50-1% Tin Oxide- 1% I was wondering if there was something else I could substitute for Ferro Frit 3271 (I also don't have the other frits they said you could use 3191, 3278) and if there was in what amount? I'm just assuming if you are substituting one thing for another the gram amount will also change. Any help would be appreciated. Link to comment Share on other sites More sharing options...
Colby Charpentier Posted March 28, 2014 Report Share Posted March 28, 2014 To substitute materials in a glaze, you're going to have to use the unity molecular formula to ensure that you're maintaining the same chemistry. Does Ferro provide material analysis of their products? With a back scattered electron analysis, you could easily do the substitution... Link to comment Share on other sites More sharing options...
Dick White Posted March 28, 2014 Report Share Posted March 28, 2014 It appears that Ferro 3271 is obsolete, in that it is not listed on Ferro's website. Ferro 3291 is not listed either, but 3278 is shown. However, a quick check of a couple of pottery suppliers doesn't reveal any inventory of this particular frit. Also, I know Kingman spar is obsolete, though I still have some. Soooo, it's off to the glaze calculation software. I found a materials analysis of 3271 on Tony Hansen's Digitalfire site, and using that I was able to create a unity analysis of the original glaze. With that as a target, I was able to recreate it as follows: Ferro frit 3134 - 11.7 Custer spar - 64.3 Whiting - 11.4 Silica - 12.6 Add: Bentonite - 2 Copper carb - 0.5 to 1 Tin oxide - 1 As always, test a small batch first. Also, note that there is no clay in this recipe, only frit and minerals, so it is going to settle out very quickly. I added bentonite to your recipe for that reason, though that may not be enough to hold it in suspension. You may need to resort to other tricks like Veegum. Good luck with it. Link to comment Share on other sites More sharing options...
Marcia Selsor Posted March 28, 2014 Report Share Posted March 28, 2014 It is a Leaded Frit. Here is a substitution list http://www.bigceramicstore.com/info/ceramics/frit_comparisons.html Link to comment Share on other sites More sharing options...
AWPottery Posted March 29, 2014 Author Report Share Posted March 29, 2014 Dick White- thank you very much. I actually did go to the Digitalfire website before posting here and didn't see that particular frit so that's why I posted here. However, I am not vary familiar with that website and am not sure where to go to on there or how to do substitutions for glazes.... is there a page on that website that explains step by step how to do this? Link to comment Share on other sites More sharing options...
Dick White Posted March 30, 2014 Report Share Posted March 30, 2014 Tony Hansen, the proprietor of the Digitalfire website, has put together an incredible compendium of information about pottery materials and processes. When you go to the Reference Database, there are tabs for materials, articles, etc. In the materials tab, things are organized alphabetically, with a page just for frits. Just scroll down the alpha/numeric list to find the frit you are interested in. As for making substitutions, first you need to understand the Seger Unity Analysis. There are web pages and sections in pottery books devoted to that. Once you understand the Seger Unity Analysis, the math and chemistry behind it is best left to a good glaze calculation program. Mr. Hansen of the above Digitalfire site offers one called Insight. Another one is GlazeMaster, by John Hesselberth, a co-author of the book Mastering Cone 6 Glazes. I prefer GlazeMaster, but only because that's the one I have and I have met Mr. Hesselberth in person. Insight is just as good. Maybe I will meet Mr. Hansen too some day (I'd like to, I hear he's an interesting fellow). Note that the glaze calculation methodology is the same for all cones, 6,10, lowfire, highfire, whatever. The difference is the target balance between the various components that will cause the glaze to melt at a lower or higher temperature. Once you have calculated the target balance of the underlying chemical oxides in a particular glaze, you can switch other materials around until you recreate the proper balance. The software makes it easy, doing all those calculations by hand would be miserable. Link to comment Share on other sites More sharing options...
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