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to keep glaze in suspension

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I have a glaze that has been formulated and mixed properly in the past. This time however I cannot stir; it settles on bottom of bucket, I have added the correct amount of bentonite as recipe calls. It is a recipe that calls for crocus martis stain. Could it be that the materials in the crocus martis has changed? Should I add an additional amount of bentonite? What is your suggestion?

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How long does it take to settle? I have glaze that I have to mix it up every 5 to 10 minutes while I'm using it because it starts settling. I use drywall mug mixer and drill and or a electric motor mixer with my glaze tank.

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You can try using a deflocculant. An addition of a few drops of sodium silicate can deflocculate the batch allowing for the use of substantially less water in your glaze slurry. Further more the addition of epsom salts also helps keep glazes in suspension and helps to stop the formation of the stone hard glaze in the bottom of the bucket.

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Just a tip . . . dissolve the epsom salt in hot water before adding to the glaze. Do not put epsom salts directly into the glaze in crystal form.

 

An epsom salt solution is good to keep on hand . . . just heat a cup of water, add epsom salts and stir to dissolve. Keep adding epsom salts until they no longer dissolve . . . even heating the solution up so you can add more. That gives you a highly concentrated jar of epsom salts water you can then just add to a glaze as needed.

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Just a tip . . . dissolve the epsom salt in hot water before adding to the glaze. Do not put epsom salts directly into the glaze in crystal form.

 

An epsom salt solution is good to keep on hand . . . just heat a cup of water, add epsom salts and stir to dissolve. Keep adding epsom salts until they no longer dissolve . . . even heating the solution up so you can add more. That gives you a highly concentrated jar of epsom salts water you can then just add to a glaze as needed.

 

 

Hi, I use Epsom salt too, and it works very well as a flocculant. I normally add a tablespoon to 1 kg of dry glaze (using the hot water as you described). How much do you add of this mixture per kg of dry glaze? I would prefer to have it ready mixed!

Diana

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Just a tip . . . dissolve the epsom salt in hot water before adding to the glaze. Do not put epsom salts directly into the glaze in crystal form.

 

An epsom salt solution is good to keep on hand . . . just heat a cup of water, add epsom salts and stir to dissolve. Keep adding epsom salts until they no longer dissolve . . . even heating the solution up so you can add more. That gives you a highly concentrated jar of epsom salts water you can then just add to a glaze as needed.

 

 

Hi, I use Epsom salt too, and it works very well as a flocculant. I normally add a tablespoon to 1 kg of dry glaze (using the hot water as you described). How much do you add of this mixture per kg of dry glaze? I would prefer to have it ready mixed!

Diana

 

I usually add a teaspoon or two at a time until the consistency improves. No set amount per kg of glaze. Seems to vary from glaze to glaze.

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Why don't you try making smaller amounts at a time and then making more glaze as is needed? If you have a recipe, you should be able to make it similar every time.

Why exactly can you not mix? Will it combine the colors too much?

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I know of a 1/2-full 5 gallon bucket of Hamada black cone 10 glaze with a toilet brush stuck in it that is gonna be the first test case for this approach, pres!

 

you will find it works best if you get that hard lump broken up and stirred with a mixer. Epsom salts does help with keeping a glaze in suspension, but does't dissolve hard lumps. I use epsom salts in my engobes that have stains in them. Stains tend to sink to the bottom. The epsom salts help there too

especially when I am airbrushing colors.

 

Marcia

 

 

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Thanks Marcia.

 

There are quite a few buckets in the studio that are bound up like this. I found that a small "toy" hoe I picked up at the Evil Empire years ago for gardening works nicely to at least get the chunk off the bottom of the bucket. From there, I take it over as a hands on thing...squishing the lumps and trying to mix em in by hand. (I always see too many bubbles using the drill)

 

I didn't mix these glazes originally, and a few have been under the cabinet for quite awhile...passed over for mixes that didn't settle as badly/etc. I see folks getting them out and NOT fully mixing them...but still using them and i wonder what that does to the overall chemistry/appearance of the glaze over time (?) I'm guessing this may be why all of my pitchers done in the studio's Malcolm Davis shino lacked variations in colors like I had hoped they'd pick up. Either that, or the firing/reduction was off. Either way....I got more of an oatmeal look than a Malcolm davis shino look.

 

The Hamada I speak of (and a few others) will seetle back out into a rock in only a few days...so it will be interesting to see if the epsom will "fix" the problem or f these glazes are kaput...

 

thanks for the tip, all

 

teardrop

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To make the bubbles go away, get a squirt bottle and mix some alcohol with water. You just need a diluted mix. The alcohol breaks the surface tension of the bubbles and they disappear. Very cool to see them vaporize instantly.

Richard Notkin uses this solution for the surface of plaster before pouring the wet plaster.

 

Marcia

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To make the bubbles go away, get a squirt bottle and mix some alcohol with water. You just need a diluted mix. The alcohol breaks the surface tension of the bubbles and they disappear. Very cool to see them vaporize instantly.

Richard Notkin uses this solution for the surface of plaster before pouring the wet plaster.

 

Marcia

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Thanks yet again, marcia. I think my instructor must be sleeping/unaware of these tricks....or maybe didn't let us in on them because it encourages folks to >add< things into the glazes and in an open studio situation where everyone is sharing you never know what was done previously. Either way....it's the first I've heard of either application and I look forward to seeing what kinda of a difference such additions may make.

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"I didn't mix these glazes originally, and a few have been under the cabinet for quite awhile...passed over for mixes that didn't settle as badly/etc. I see folks getting them out and NOT fully mixing them...but still using them and i wonder what that does to the overall chemistry/appearance of the glaze over time (?)"

 

In an open studio situation the glazes are not likely to be the exact recipe unless you get some two minutes after it was mixed. Especially white. Why do people think they can get away with just a quick dip when they have another damp glaze already on the pot? Or they just scrape a bit of the colored glaze off then blow to get rid of dust leaving little specks of color in the glaze bucket? Or as you say, they don't mix it well then use the top layer. Or add water because they think it's too thick? Or throw out the water sitting on top because they think it's too thin? We humans are a trying bunch!

 

My blessings and heartfelt good wishes go out to all the studio managers who deal with these issues with diplomacy and tact. You are the front line of pottery education and I am 100% positive I have driven some of you crazy at various points!

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LOL. I'm definitely looking at buying my own glazes for class, chris!

 

FWIW, the only person who was asked to not come back (wasn't me, believe it or not..LOL) to class was a lady who poured about 3 gallons of glaze out of a 5 gallon bucket and then..after a few dips...stated that she "couldn't remember what bucket she got it from".....and proceeded to start to just dump it in the nearest/open bucket!!

 

Fortunately a few other students stopped her...but it took repeated attempts because she just couldn't wrap her head around the individuality of the mixes...

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I think I might have responded to this question before, but I am going to give it a go again. Glazes settle out if there is not a lot of plastic clay like ball clay in them. If you have a lot of heavy materials like fritts or flint/silica, they will sink like a rock. What you do is get your pear shaped trimming tool and get the glaze up from the bottom. If you know the amount of glaze you mixed up, you can add up to 3% bentonite. This also makes the unfired glaze surface harder-better for brush decoration. I don't like using Epsom salts as this changes the chemical makeup of the glaze, and the electrical charge. It is a quick solution though.

TJR.

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All above ideas work well but for really settling glazes we have had great results with product called Magma

Its a bit of trouble to mix up but it works as nothing else does-even gums

we keep some mixed in sealed tub to add when we need it.

Mark

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Epsom salts (magnesium sulfate) are my go-to for suspension issues, but you really do need have at least 8%, ideally 10% or more, of clay in your recipe, like EPK or Ball Clay. The idea is that the clay suspends well, but everything else likes to settle. The Epsom salts, a flocculant, get everything to stick to the clay, thus keeping it suspended. Without enough clay in the recipe you're just sticking together ingredients that will settle whether they're stuck together or not. Adding 2-3% bentonite (a super plastic clay) will help a lot, without affecting the glaze appearance. But it must be added to the dry mix and thoroughly mixed before adding water, or it will clump up really really badly.

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I use epsom salts - a couple of teaspoons per kilo of glaze. I've found it keeps glazes from settling into a hard lump in the bottom of a bucket, even if the glaze is not used for months, or even years.

That includes crystal glazes with no clay, or one of the raku glazes I use which is - frit 100 bentonite 5.

Cheers. Graeme

 

 

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Epsom salts. I have found that adding 1.6% by weight to glazes that are heavy in Neph Sye or frit and light on clay works well. I adjust (lower) the 1.6% when I have a glaze that has clay and/or bentonite and still settles out. I do keep a solution handy for adjust after mixing but prefer to make a note on the next glaze batching to add it dry to the rest of the dry glaze mix. That way I have more control over time. When adding dry, I use hot water which I add by weight also. Usually start with 80% water by weight and adjust to the ingredients in the mix. So a 4540 gram batch (10 lbs of dry ingredients) uses 3632 grams of water to start and then adjust by adding a little more as needed. 3632 grams of water converts to 8 lbs.

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I remember reading an article in Ceramics Monthly (I think) in which it was stated that some glaze ingredients absorb water only over time; so that they don't settle at first, but later. I have a glaze that does this, it's a 4-3-2-1 glaze. I kept meaning to go back and read that article, and now I can't remember what issue it was in. Anyone know?

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