Zinc Oxide Recipe Mishap

[noobatthishalp 3]

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.

 

[Callie Beller Diesel 1,802]

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?

[kristinanoel 22]

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

[neilestrick 3,438]

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....

[liambesaw 1,687]

I'm guessing the zinc helps clear the surface of bubbles from the whiting?  Hard to say... 

[noobatthishalp 3]

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

[liambesaw 1,687]

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

[noobatthishalp 3]

unfortunately the deadline is friday and I am flat broke, otherwise Id just go to the local ceramic place and do that

[Min 2,357]

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? 

[noobatthishalp 3]

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

[kristinanoel 22]

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/ 

[noobatthishalp 3]

cause its supposed to be glaze experiment where were supposed to make our glaze, its not supposed to be perfect

 

[kristinanoel 22]

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. 

 

[noobatthishalp 3]

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

[liambesaw 1,687]

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.

[Bill Kielb 649]

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.

[Babs 919]

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:-)))