Glaze Layering vs. Mixing Question

[NanS]

Hello -- I've been experimenting with a bunch of glazes, some commercial and some I've mixed myself. I have a question about a combo that I'm interested in, which is two commercial glazes layered.  (The glazes are Curry from Spectrum and Red Rooster from Opulence. I've included my test tile. My clay is a red-brown stoneware from Sheffield Pottery, Cone 6.)  I like the way they look layered, and am wondering if I mix these two glazes is it a safe guess that I would get basically the same result color and texture -wise?   I'd like to mix them to get more even coverage.  I know the right answer to this question is to test it and see for myself, but I'm wanting to use this combo before filling the kiln a whole other time.  Is there a rule of thumb with this?  Thanks!

[Bill Kielb]

Generally layered glazes provides some properties of each glaze and are very different than mixing the glazes in advance in one uniform solution. It’s pretty unlikely in my view that a mixed result will resemble a layered result so yes, testing is the only way to know for sure in my experience.

Edited December 27, 2022 by Bill Kielb

[NanS]

Thanks Bill, that's a really helpful answer and just what I needed to know.  Much appreciated.

[Callie Beller Diesel]

Not only will a homogeneous mix of 2 glazes give you a different result than the same 2 glazes layered, the order in which you layer them will often give you a third set of results. And varying the thickness of the application in any of those scenarios can add yet another layer of interactions.

There’s lots of us that can give you a super technical rundown if you love the science, but the simple explaination is that when you layer the glazes you’re creating localized areas of 3 (or more) different chemical reactions. There’s areas on the pot of glaze 1, glaze 2, and whatever the mix of the 2 of them would be. When you mix the 2 thoroughly, you’re only getting the one thing. 

[neilestrick]

Unfortunately, mixing will usually give you a completely different result. It would be nice if mixing worked, as the whole process would be a lot simpler!

[Magnolia Mud Research]

mixing two glazes: 
call them glaze A and B.

This is a standard glaze assignment for the college Ceramics II.  
There are various combinations  A over B; B over A; A mixed with B;
Expect three different fired outcomes.

The above assumes that the amounts of glaze per area of A and B are applied equally.  

The forth set is to use different amounts of glaze per area also, which will also provide even more different outcomes.  

my recommendation: make a large set of test pieces and find the outcome you prefer.   

LT

[Chilly]

13 hours ago, Magnolia Mud Research said:

my recommendation: make a large set of test pieces and find the outcome you prefer.

@NanSand get lost down a rabbit hole forever.  I could spend my entire "pottery" time lost in testing glazes and combinations.

[NanS]

Thanks Y'all!  I kind of knew in my heart of hearts that it wasn't going to be so easy ( - :  I've already tested A over B and B over A.  Now I'm going to test A mixed with B.  Appreciate the wisdom and advice!