White Glaze

[BlackandWhitedogpottery]

Hello Everyone!

 

This is my first official time at making a glaze from scratch. Its a simple white glaze from a Lucie Rie recipe, fired to ^6 oxidation 

 

58 Soda Feldspar

 

14 China Clay

 

10 Zinc Oxide

 

10 Tin Oxide

 

  8 Whiting

 

  8 Flint  

 

Now I cant exactly find the ingredients listed on here but I think I've found the equivalents. Such as Minspar 200 (F4) , Kaolin, and Silica 325 mesh. So the recipe would look like this?

 

 58 Minspar Feldspar 200 (F4)

 

 14 Kaolin 

 

 10 Zinc Oxide

 

 10 Tin Oxide 

 

   8 Whiting (calcium carbonate 325)  

 

   8 Silica    (325 mesh)

 

Does this look like it would work? 

 

I am hoping this will be a bright white stark white I can use on my creamy beige stoneware. 

[MatthewV]

Yes.

 

Soda Feldspar will change with the location of the mine etc etc. Minspar Feldspar 200 (F4) is a soda feldspar (and this F4 variety can no longer be easily purchase)

China clay is another name for a kaolin.

Flint is a different word for silica (most of the time, in this context it is)

 

---

Using Tin Oxide for opacity is expensive. I would look to using Zircopax (zirconium oxide) instead. 

 

---

A good white is actually one of the harder glazes to formulate in my opinion.

[BlackandWhitedogpottery]

Yes.

 

Soda Feldspar will change with the location of the mine etc etc. Minspar Feldspar 200 (F4) is a soda feldspar (and this F4 variety can no longer be easily purchase)

China clay is another name for a kaolin.

Flint is a different word for silica (most of the time, in this context it is)

 

---

Using Tin Oxide for opacity is expensive. I would look to using Zircopax (zirconium oxide) instead. 

 

---

A good white is actually one of the harder glazes to formulate in my opinion.

 

Yeah I noticed that, what is it with tin oxide that makes it almost $30.00 per lbs. I wonder?

 

I think I will also purchase the Zircopax too, I've heard it creates an industrial bright white also.  

 

So what would be the percentage of replacing the tin with Zircopax, maybe 8- 10%?

[High Bridge Pottery]

Tin oxide certainly makes a better white in my opinion but it sure costs more. Test both to see which you prefer as even though it is expensive I still use Tin Oxide. In the end a 10kg glaze bucket costs me between £8 - £15 even using 'premium' ingredients and covers 100's of pots. You are already laughing when 10kg of powdered glaze from a supplier is 5x that price.

 

On the make up of the glaze, looks good for a quick eyeball. Maybe include some kind of frit in your shopping, used quite a bit at cone 6 and a good quick fix for glazes that don't like to melt very well.

I have found over in the UK most felspars have similar melting properties but bring colour too. Soda feld was on the blue side and potash towards the pink. Cornish stone was the whitest white but I think it was the worst melter so had unmelted silica making it quite white.

[PeterH]

This is my first official time at making a glaze from scratch. Its a simple white glaze from a Lucie Rie recipe, fired to ^6 oxidation

I associate Lucie Rie with a time long before ^6 became popular. Are you sure that this glaze is intended for ^6?

 

PS

Had a quick look and found this posting, suggesting a significantly higher firing temperature.

Also note the possibility of crawling when used on bisc.

 

http://community.ceramicartsdaily.org/topic/368-lucy-rei-glazes/

Miri, I share your love for Lucie Rie's work. I have one recipe (copied long ago from a UK ceramics book but never used) attributed to her. Here is the text (verbatim with commentary) from the book:

 

Lucie Rie's White (oxidized, 1,250°C)

 

58 soda feldspar

14 china clay

10 zinc oxide

10 tin oxide

8 whiting

8 flint

 

This glaze is the famous glossy white glaze used on Lucie Rie's tableware, often stained brown with manganese and copper carbonate on the rims. It can be tried with less tin - 5 or even 2 percent - but is expensive to make, and inclined to crawl when used on biscuit ware, perhaps because of the high zinc content. Lucie Rie's pots, of course, are once fired, which avoids this problem.

[oldlady]

this recipe is for a bright white shiny glaze.  to see the color, look in my gallery for the interior of the empty bowls.

 

Wettlaufer XS   cone 6

 

Kona soda spar              40

whiting                            20

silica 325                        20

ball clay C&C                  10   i use C&C because it is so white    OM4 is dirty looking

zinc oxide                         5

zircopax                           20

[BlackandWhitedogpottery]

Tin oxide certainly makes a better white in my opinion but it sure costs more. Test both to see which you prefer as even though it is expensive I still use Tin Oxide. In the end a 10kg glaze bucket costs me between £8 - £15 even using 'premium' ingredients and covers 100's of pots. You are already laughing when 10kg of powdered glaze from a supplier is 5x that price.

 

On the make up of the glaze, looks good for a quick eyeball. Maybe include some kind of frit in your shopping, used quite a bit at cone 6 and a good quick fix for glazes that don't like to melt very well.

I have found over in the UK most felspars have similar melting properties but bring colour too. Soda feld was on the blue side and potash towards the pink. Cornish stone was the whitest white but I think it was the worst melter so had unmelted silica making it quite white

 

 

 

 

What type of Frit would you recommend for this glaze? There's quite a few to pick from and I'm not quite sure.

 

Also, is there a way to increase the pinholing in this? I know this is a defect but I would like to have this glaze  good and smooth in the interiors and subtle pinholed on the exterior. Maybe increase the whiting? I think if the kaolin was increased the glaze would be more prone to shivering?

[BlackandWhitedogpottery]

this recipe is for a bright white shiny glaze.  to see the color, look in my gallery for the interior of the empty bowls.

 

Wettlaufer XS   cone 6

 

Kona soda spar              40

whiting                            20

silica 325                        20

ball clay C&C                  10   i use C&C because it is so white    OM4 is dirty looking

zinc oxide                         5

zircopax                           20

 

That glaze looks great! Thanks for sharing this recipe, I might just go with this if the glaze isn't how I imagined.

[High Bridge Pottery]

Not so good with my USA frits, 3110 and 3112 I think are posted about a lot.

 

I would get one with a good chunk of boron in. The one I use in the uk is 50% boron but I remember that not being a easily available frit and you guys get about 25% boron. Anything with boron

[oldlady]

joel, i just entered "frit 3124" on my computer and lots of stuff came up.  another popular one is 3134.  both by Ferro.

[BlackandWhitedogpottery]

So this is the result of the first recipe, the perfect shade of white for me, perfect gloss at ^6.

 

Just one issue...Magnificent crawling.

 

I applied it in the greenware state. The consistency was about thick as yoghurt and brushed on 2-3 coats. I noticed it didn't crawl in the thinner spots where I applied the glaze. Maybe it needed to be thinned down a little bit more and brushed on finer layers  but I believe it could be from the high zinc content and maybe I fired the kiln too fast.

 

Any tips for crawling?

[C.Banks]

This sure sounds/looks like too thick an application.

 

Yoghurt for me resembles a slip more than glaze.

 

Now a nice, thickish gravy...maybe beef...over Yorkshire pudding...yum...

 

[High Bridge Pottery]

The zinc doesn't look too high but it certainly can make glazes crawl. I wouldn't think anything under 10% would do this much crawling but then there isn't much clay in the recipe to help crawl either. Could be an application issue as C.Banks says or maybe a greenware issue, but I have never tried glazing greenware before so unsure about that one.

 

There are a few recipes posted so not sure which you went with in the end. Although they are all similar.

[oldlady]

why are you using a brush for application?  do you have enough for dipping or pouring?  if you make it a little thinner, and dip, maybe the problem will go away.  lots of tests in your future.

 

i use the white recipe i gave you on greenware but i spray it on for even application.  it is not thin when i use it.

[Babs]

You applied this to Greenware.

Think you need a lot more clay in your recipe to use this as a raw glaze...about 20-30% from memory.

Haven't used raw glazing for years so check it out.

[rayaldridge]

I think adding a little frit might help, and a lot of single-firers do use a spray application.  Also, it's been my experience that with some glazes, brushing on multiple layers can lead to glaze faults, because the second layer can sometimes loosen the first layer.

 

This may seem like a dumb question, but I'm curious as to why you tested this on full-size pots rather than on test tiles.  If you use tiles, it's easier to test multiple factors-- you could try different application methods, and different stages of dryness.  When I single-fired, I dipped glaze onto leatherhard pots rather than dry pots-- because glazing dry pots gave me more problems.  Doing it that way would require more plastic clay in the recipe, probably. 

 

Though I think when working with this glaze, I'd use pretty big test tiles, since there are areas of your example that aren't crawling badly.

 

Also, I have to admit that I don't like using zinc in glazes, for a couple reasons.

[BlackandWhitedogpottery]

why are you using a brush for application?  do you have enough for dipping or pouring?  if you make it a little thinner, and dip, maybe the problem will go away.  lots of tests in your future.

 

i use the white recipe i gave you on greenware but i spray it on for even application.  it is not thin when i use it.

 

I've had problems with pouring and dipping in the past, even on bisque wares I could never get that smooth finish it usually ended up with lots of drips all over the piece and puddles. If I pour on the greenware it will always crack apart 100% of the time, my pieces are on the thinner side.  Most of the time I just brush on a good 3-4 coats on the inside, set it aside then do the outside and usually everything is fine. (except this one) I have more test firing right now with thinner glaze so we'll see.

[BlackandWhitedogpottery]

I think adding a little frit might help, and a lot of single-firers do use a spray application.  Also, it's been my experience that with some glazes, brushing on multiple layers can lead to glaze faults, because the second layer can sometimes loosen the first layer.

 

This may seem like a dumb question, but I'm curious as to why you tested this on full-size pots rather than on test tiles.  If you use tiles, it's easier to test multiple factors-- you could try different application methods, and different stages of dryness.  When I single-fired, I dipped glaze onto leatherhard pots rather than dry pots-- because glazing dry pots gave me more problems.  Doing it that way would require more plastic clay in the recipe, probably. 

 

Though I think when working with this glaze, I'd use pretty big test tiles, since there are areas of your example that aren't crawling badly.

 

Also, I have to admit that I don't like using zinc in glazes, for a couple reasons.

 

I think it would help if I added some kind of bonding agent like a gum to help keep lay the layers down so they don't lift off when brushing.

 

I make quite a few pots and I like to use the ones that I trimmed through/cracked for testing because it makes sense to me to use the glaze on actually pots because the glazes acts differently on different forms besides tiles. It also factors in how this glaze will react to a trimmed surface (usually pinholes) and a surface smoothed with a rib, how easy it is to apply on the banding wheel and how it will work on the underside of the footring. I would just hate to develop a glaze that worked well on a test tile but doesn't work for my tablewares. 

 

I never thought about leather hard glazing, will try that for sure.

[BlackandWhitedogpottery]

Latest results. Added a good bit of acrylic glazing medium and a few drops of dish soap to make it more brushable and it really worked this time.

[PeterH]

Congratulations.

 

How are you firing them?

[oldlady]

very nice!  congrats.

[Pres]

I have often used tin oxide as an opacifier to create a hard white. As others have said here cost can be prohibitive, and it is for me also. I have tried to modify my whites by playing with percentages of varying opacifiers. I have used percentages of tin, zircopax, titanium, and even rutile to soften or sharpen white. These also have a tendency to change what happens in the way of flashing from chromium that some abhor and others love. It can also change the hue of the glaze to a slight yellow that works especially well with Rutile blue and green  glazes where yellow enhances the glaze over top. Perfect white for one is not for another, but I would hope that more investigation into the chemistry of white with more testing will help folks to understand ways to moderate cost and find their perfect white.

 

best,

Pres