noobatthishalp 3 Posted December 5, 2019 Report Share Posted December 5, 2019 Hey yall, I am a student and currently have a glaze making assignment for my class and I found a recipe that goes (in grams): custer feldspar 99 talc 63 silica 48 EPK 45 Whitening 36 zinc oxide 9 +22.5 titanium oxide 6 copper oxide black 6 copper oxide red I got through making most of the recipe and then found out we dont have the zinc oxide, is there something I could replace it with? I dont care if it ends up not being the color I want as long as it ends up as a high fire glaze. Im very new at this and have no idea what Im doing, please help. Quote Link to post Share on other sites
Callie Beller Diesel 2,546 Posted December 5, 2019 Report Share Posted December 5, 2019 Zinc is a flux, and an odd one to use at cone ten. It melts early and stays fluid for a wider temperature range, so it’s more usual at cone 6, in very fluid glazes, or in crystalline glazes. In the quantity it’s in and without running it through glaze calc software, it’s probably there to give some kind of visual effect involving running or fluidity. Maybe to clear bubbles? Where did you find this glaze and what is it supposed to do? Quote Link to post Share on other sites
kristinanoel 35 Posted December 5, 2019 Report Share Posted December 5, 2019 You could just leave it out and see what happens. You've got talc and whiting, which are also fluxes, and not that much zinc oxide anyway. Think about what each of the elements is meant to do, make glass, stick to the pot, or help the glaze melt. As my professor was fond of saying: "Might work, might not. Try it and see." Glassmakers / Glaze Cores custer feldspar 99 silica 48 Binders EPK 45 Fluxes talc 63 Whitening 36 zinc oxide 9 Colorants +22.5 titanium oxide 6 copper oxide black 6 copper oxide red Rae Reich 1 Quote Link to post Share on other sites
neilestrick 4,592 Posted December 5, 2019 Report Share Posted December 5, 2019 You've got 3% zinc in there, which is probably enough to make a difference in the melt. You could try leaving it out, or replace it with another flux and see what happens. Zinc does give the melt a certain appearance, so it may not look the same. Worth a try.... Quote Link to post Share on other sites
liambesaw 2,751 Posted December 5, 2019 Report Share Posted December 5, 2019 I'm guessing the zinc helps clear the surface of bubbles from the whiting? Hard to say... Quote Link to post Share on other sites
noobatthishalp 3 Posted December 5, 2019 Author Report Share Posted December 5, 2019 the glaze was originally a gloss green with pink speckles, if the zinc was supposed to get rid of bubbles then what should I use instead to manage the bubble problem? Thanks to all of you for helping out btw Quote Link to post Share on other sites
liambesaw 2,751 Posted December 5, 2019 Report Share Posted December 5, 2019 (edited) Can you just buy a pound of zinc oxide from a pottery supply place locally? Or even order it from a place like uspigment.com? It's very very cheap. Edited December 5, 2019 by liambesaw Quote Link to post Share on other sites
noobatthishalp 3 Posted December 5, 2019 Author Report Share Posted December 5, 2019 unfortunately the deadline is friday and I am flat broke, otherwise Id just go to the local ceramic place and do that Quote Link to post Share on other sites
Min 3,428 Posted December 5, 2019 Report Share Posted December 5, 2019 I'ld split the test in half, try one version without the zinc and the other half with another flux. What other fluxes do you have? Rae Reich, kristinanoel and Callie Beller Diesel 3 Quote Link to post Share on other sites
noobatthishalp 3 Posted December 5, 2019 Author Report Share Posted December 5, 2019 Thats a good idea, Ill let you know what I do when Im done with class or during depending on what goes on. Ill also show yall how it turned out when they come out of the kiln Quote Link to post Share on other sites
kristinanoel 35 Posted December 5, 2019 Report Share Posted December 5, 2019 Also - what exactly is the assignment? To find and test a cone 10 glaze recipe? Why not just find a different recipe that only calls for stuff you have? https://glazy.org/ Quote Link to post Share on other sites
noobatthishalp 3 Posted December 5, 2019 Author Report Share Posted December 5, 2019 cause its supposed to be glaze experiment where were supposed to make our glaze, its not supposed to be perfect Quote Link to post Share on other sites
kristinanoel 35 Posted December 5, 2019 Report Share Posted December 5, 2019 Well there you go. Leave out the zinc oxide and it won't be perfect! (Might not even be perfect if you had the zinc.) Win-win. Rae Reich 1 Quote Link to post Share on other sites
noobatthishalp 3 Posted December 5, 2019 Author Report Share Posted December 5, 2019 just heard from a classmate that we should have zinc which means that both I, and the ceramics assistant are blind. Either way Ill post the results of how my glaze turns out kristinanoel, liambesaw and Rae Reich 3 Quote Link to post Share on other sites
liambesaw 2,751 Posted December 5, 2019 Report Share Posted December 5, 2019 31 minutes ago, noobatthishalp said: just heard from a classmate that we should have zinc which means that both I, and the ceramics assistant are blind. Either way Ill post the results of how my glaze turns out Yeah it would be pretty amazing to me if you didn't have such a common ingredient in your school, but it's possible someone used the last of it without reordering. If your school has a chemistry department you may call up and ask if they have zinc oxide powder they can spare. Callie Beller Diesel 1 Quote Link to post Share on other sites
Bill Kielb 1,114 Posted December 5, 2019 Report Share Posted December 5, 2019 2 hours ago, noobatthishalp said: just heard from a classmate that we should have zinc which means that both I, and the ceramics assistant are blind. Either way Ill post the results of how my glaze turns out Hopefully you find it, then research Bristol glazes to impress your instructor. It often was a way for a subset of funny little glazes to lower the melt. Not saying this is one but zinc @ 0.2-0.4 in a 0.70 RO base Often was used to lower the melting point, no boron required. Rae Reich 1 Quote Link to post Share on other sites
Babs 1,203 Posted December 6, 2019 Report Share Posted December 6, 2019 6 hours ago, noobatthishalp said: cause its supposed to be glaze experiment where were supposed to make our glaze, its not supposed to be perfect So you are using one you "found":-))) Time management 101 rwco.mendwd for next semester:-))) Quote Link to post Share on other sites
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