Using mason stains in magnesium matte recipe?

[brooksms]

Recipe #1 (minus the cobalt): https://glazy.org/recipes/151716

Recipe #2, low magnesium, haven't tested yet: https://glazy.org/recipes/472422

I'm new to pottery and making glaze. The 1st recipe covered my dark clay well and made a nice texture so I've ordered mason stains to play with. I've seen a very vague mention of magnesium not playing well with some so I'm looking for insight before starting. The main info I have is on the mason stain reference page here. The two green shades I ordered say they're best without zinc and I saw a correlation with magnesium, so it's possible I might have trouble with green...? A couple of the colors say they'd do better with some zinc in the recipe, the rest I ordered are fine with or without it. Does anyone know how much should be added? I don't see any zinc on the analysis for either recipe.

Since the top recipe makes white rather than clear, is it best to keep it as-is when wanting vibrant colors or should I remove the zircopax? I read somewhere that mixing into white will make more pastel colors, which is actually what I want to start with. A test I saw without zircopax didn't cover darker clay so I don't see the recipe working without it.

Thanks for any thoughts you have on this! It's just a hobby during the little free time I have very little understanding of the chemistry. 

Colors ordered: walnut, dark red, canary yellow, French green, grass green, turquoise, copen blue, onxy, Saturn orange, lavender and coral.

[Min]

7 hours ago, brooksms said:

Does anyone know how much should be added

I wouldn’t use either of those glazes if you are new to glaze chemistry as it would be necessary to remove some of the other fluxes in order to add zinc. If you just added zinc then the glaze would have more flux than needed to create a balanced glaze. Result would be an excessively fluid glaze.

Glazes high in magnesium tend to have a more muted response to colourants than those without high levels of it and blues  from cobalt lean more towards purple tones.

Yes, zircopax will give more of an opaque glaze, with or without stains. Starting at around 5% addition will show, 10% will be opaque on most bodies. 

A green stain that contains chrome when put in a glaze containing zinc will most often give an unpleasant brown.

Your second link didn’t work for me.

Welcome to the forum.

[brooksms]

16 minutes ago, Min said:

I wouldn’t use either of those glazes if you are new to glaze chemistry as it would be necessary to remove some of the other fluxes in order to add zinc. If you just added zinc then the glaze would have more flux than needed to create a balanced glaze. Result would be an excessively fluid glaze.

Glazes high in magnesium tend to have a more muted response to colourants than those without high levels of it and blues  from cobalt lean more towards purple tones.

Yes, zircopax will give more of an opaque glaze, with or without stains. Starting at around 5% addition will show, 10% will be opaque on most bodies. 

A green stain that contains chrome when put in a glaze containing zinc will most often give an unpleasant brown.

Your second link didn’t work for me.

Welcome to the forum.

Thank you so much for the info! That is very helpful. The 2nd link works for me so idk, but it is a low magnesium recipe so I thought it might be a good alternative for brighter colors. I'll skip over colors requiring zinc for now since my brain isn't ready to swap fluxes else just yet.  

[Callie Beller Diesel]

Hi and welcome!

Stains are fun to work with, especially for us dark clay users. And the reference chart you’ve already found is a very good reference is this section of Digitalfire. Tony identifies the stain by number, which is a good practice as there are 3 different numbered stains with the name “dark red” and they all have slightly different chemistry.Tony’s got examples of the Canary Yellow and Turquoise in a magnesium matte glaze base, so you can see how those 2 respond, at least.

Speaking of recipes: the second  link you’ve shared comes back as a “does not exist” error. If this is a recipe on your own page, make sure it’s published so we can see it. 

Zircopax won’t make the colours pastel: glaze colour theory doesn’t work the same as paint. If anything, it’ll make it brighter and more saturated, because more of the colour is reflected back to your eyes. 

 

[brooksms]

14 hours ago, Callie Beller Diesel said:

Hi and welcome!

Stains are fun to work with, especially for us dark clay users. And the reference chart you’ve already found is a very good reference is this section of Digitalfire. Tony identifies the stain by number, which is a good practice as there are 3 different numbered stains with the name “dark red” and they all have slightly different chemistry.Tony’s got examples of the Canary Yellow and Turquoise in a magnesium matte glaze base, so you can see how those 2 respond, at least.

Speaking of recipes: the second  link you’ve shared comes back as a “does not exist” error. If this is a recipe on your own page, make sure it’s published so we can see it. 

Zircopax won’t make the colours pastel: glaze colour theory doesn’t work the same as paint. If anything, it’ll make it brighter and more saturated, because more of the colour is reflected back to your eyes. 

 

Ahh you were right, the recipe was set to private, all fixed! Thank you for the insight & link. Good to know about zircopax, I'll start with a low % stain and work my way up. I don't know if I'm looking the wrong way but I didn't see many mason stain glaze tests on glazy. Feels like I'm going in blind!

[Callie Beller Diesel]

I don’t know if this is still holding true with newer folks, but mason stains used to be considered “cheating.” 

Absurd purist ideas aside, sometimes they can give rather flat “candy coating” results if they’re not modified somehow, or used in an off label way. Off label usually meaning in a lower concentration or with less/no zircopax than usually recommended if you want them to give a more translucent result, or combining them with some rutile to give visual depth, etc.  And of course, you’ve already encountered the varying base glaze requirements for making sure they turn out as intended. Glaze testing can get really pedantic and boring, and it’s easy to get turned away if you don’t see some kind of positive or interesting result on the first round or 2. 

 

[brooksms]

That makes sense, lots of potters attached to old school ways of thinking. I recipe test for my career so my brain just doesn't have the capacity, needs a little cheating lol. It will be very interesting to see how the tests turn out. At the very least I'll share results so others will know!

[Rae Reich]

I agree that stacks of test tiles can get fiddly and overwhelming but tests are so useful! I’ve made simple reference pots for my stain tests using bisque, straight-sided mugs, cups or bowls of the preferred clay, one for each base glaze, and as many small deli cups as you have stains to test.

Dip the pot almost halfway into the glaze and let dry.

Mix 1/8 tsp of stain into 1T of base glaze in each carefully marked deli cup and stir up, add a little water to make it brushable, if needed.

Paint 1/2” wide vertical stripes of each color from top to bottom, over the dipped glaze and over the bare clay.

Dip the bare end of the pot almost halfway into the base glaze, covering the stripes, and let dry. There will be a space between dips to show you what the stain in a bit of base looks like on bare clay - handy for white clays.

After the firing, use a sharpie to label the stain stripes with the stain numbers. Make notes if you want to try different proportions in a future test.

I use these little deli cups to decorate from, mixing more as needed (stains are expensive!) and letting them dry up between uses, adding water by drops to rehydrate.

NOTE: be sure you make note on the pot of which end is Glaze Over and which is Glaze Under. It won’t always be obvious  

 

 

Edited May 15 by Rae Reich