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Turquoise Lithium glazes - issue with crawling


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Hi there

I've tried many different turquoise lithium glazes (from the John Brit cone 6 book) and from various other sources including Glazy.   However i have a real problem with crawling/pitting.  Test tiles are good but anything larger i'm finding these lithium glazes to be so sensitive and i'm  at the point of giving up.

Is this a well known issue with lithium glazes? I've tried spraying, dipping and pouring but still have the same issues.  I also make sure that the pots are dust free before i glaze them.

Would controlled cooling of the glaze firing help?  Are there any other suggestions that might help make the glaze a bit more friendly or are glazes with lithium always a pain in the you know what? :-)

Thanks!

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Yes its true pitting on them is always going to be an issue-its the nature of these glazes to flaw.Ceramics is not easy-maybe a slow heat cylce at the end will lay down the bubbles in final melt.

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Lithium carb has a super high LOI of just under 60%, if your glazes have high levels of lithium carb this can cause crawling (and shivering of the glaze).  Supplying the lithia content with a high lithium frit, such as Fusion F-493, can help with the shrinkage/crawling issue, also helps avoid the solubility issue with using lithium carb. Might also be able to reformulate using spodumene to supply the lithia but not always possible with high lithia amounts. Post the names or links to some of the recipes you've tried and your glaze firing schedule. 

Edited by Min
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On 5/27/2020 at 4:54 PM, Min said:

Lithium carb has a super high LOI of just under 60%, if your glazes have high levels of lithium carb this can cause crawling (and shivering of the glaze).  Supplying the lithia content with a high lithium frit, such as Fusion F-493, can help with the shrinkage/crawling issue, also helps avoid the solubility issue with using lithium carb. Might also be able to reformulate using spodumene to supply the lithia but not always possible with high lithia amounts. Post the names or links to some of the recipes you've tried and your glaze firing schedule. 

what does LOI mean?

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3 hours ago, EKasse said:

what does LOI mean?

LOI stands for loss on ignition and usually ends up as the amount of water driven off as the material fires. So generally the higher the LOI the more off gassing is the thought. It also generally means by weight, the sample is diluted by all the water. Materials with high LOI are less concentrated if you will, as a part of their weight is the weight of the water.

Edited by Bill Kielb
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If you want a nice glossy turquoise, here is one that I and an associate at my studio developed, derived from Val's (Cushing) Turquoise from years ago that became non-functional in recent times because of the material changes in Custer Feldspar and Gerstley Borate. We did some initial brute force adjustments with glaze chem software, but the color changed. After running several Currie grids, we learned that the turquoise color in this glaze is extremely sensitive to the silica level. After further experimentation, this recipe has the turquoise color and is stable with the both lemon test and a month in the dishwasher.

DJ's Turquoise

EPK - 7.7

Gerstley - 16.8

Custer - 27.3

Silica - 36.6

Whiting - 8.8

Dolomite - 2.8

add:

Bentonite - 1

Copper carb - 3

 

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2 hours ago, Dick White said:

If you want a nice glossy turquoise, here is one that I and an associate at my studio developed, derived from Val's (Cushing) Turquoise from years ago that became non-functional in recent times because of the material changes in Custer Feldspar and Gerstley Borate. We did some initial brute force adjustments with glaze chem software, but the color changed. After running several Currie grids, we learned that the turquoise color in this glaze is extremely sensitive to the silica level. After further experimentation, this recipe has the turquoise color and is stable with the both lemon test and a month in the dishwasher.

DJ's Turquoise

EPK - 7.7

Gerstley - 16.8

Custer - 27.3

Silica - 36.6

Whiting - 8.8

Dolomite - 2.8

add:

Bentonite - 1

Copper carb - 3

 

Dick how about one for cone 10? as well.

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On 6/2/2020 at 6:21 PM, Dick White said:

If you want a nice glossy turquoise, here is one that I and an associate at my studio developed, derived from Val's (Cushing) Turquoise from years ago that became non-functional in recent times because of the material changes in Custer Feldspar and Gerstley Borate. We did some initial brute force adjustments with glaze chem software, but the color changed. After running several Currie grids, we learned that the turquoise color in this glaze is extremely sensitive to the silica level. After further experimentation, this recipe has the turquoise color and is stable with the both lemon test and a month in the dishwasher.

DJ's Turquoise

EPK - 7.7

Gerstley - 16.8

Custer - 27.3

Silica - 36.6

Whiting - 8.8

Dolomite - 2.8

add:

Bentonite - 1

Copper carb - 3

 

thanks for this - i'll give it a try!  i assume it's cone 6?

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Van Guilder has a glossy Teal Blue that some would consider a turquoise, it doesn't use gerstley. I think the glaze can be found on line. I won't post it because it is his. If you have his book it is in there, and I think it is posted on Pinterest.

 

best,

Pres

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pres, van gilder used the cone 6 glazes in his  book but since he fires only at cone 10, they came from another potter.   i have seen the recipes published by others in many places.  

that teal recipe was awful on my clay, looked like flat wall paint and not at all turquoise.

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I'm really liking Van Gilder's Teal Blue (from his book, cone 6) - that's it on "small bowl" in my album (over red clay). It behaves well - goes on nicely (sg ~1.41, gelled a bit with Epsom salt), melts smooth, doesn't move much...

The base is familiar 5x20, 'cept the frit is 3124, where the 5x20 frit is 3134. Mighty Mud mixer has the recipe; try searching Van Gilder Teal Blue ...it's more teal than turq, for sure.

Edited by Hulk
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pres, the recipe for the rutile green that VG put on many of his pots in the book, is a great base glaze when used with other mason stain colors.   i found the rutile green on its own to be pretty pitiful.   i got a really nice yellow, several blues with varying amounts of cobalt carb and some pinks.  all my tests were on white clay.

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Am also liking Variegated and Rutile Green from Van Gilder's book (Wheel-Thrown Pottery). Here's some Rutile Green results, top left, then clockwise, over Aardvark Cassius, SRF, Buff, Buff; Clay Planet Venus White; Aardvark Sedona Red, Sedona Red (still working on a liner for the Sedona, arrg!) again ...different on each clay, for sure! Will check if I've a sample over Aardvark Bmix out there. I like them all (no accounting for taste, eh?)

 

notmehtome.jpg

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Ah, found it! Same Rutile Green (from Bill Van Gilder's book) as above, over Aardvark Bmix (on the lower part; the upper is a commercial blue).

 

aamug.JPG

Hi dhPotter! That vase is sold - looks like the color of the clay is showing through there, not sure why - may have been a smear of clear that wasn't wiped all the way off, or fuming from a neighbor pot? Have found it worthwhile to fill the chatter marks before glazing. I'm brushing underglaze or glaze, then wiping away, leaving the chatter marks filled, allowing the pot to dry out, then dipping, hence, may have left a film of glaze there on that vase.

Edited by Hulk
resized, and reply
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