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Deflocculate, Or Toss It And Start Over?


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#1 Stone Spiral

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Posted 16 March 2017 - 09:39 PM

I inherited a lot of glazes from a retiring potter and they have been sitting for well over a year, maybe more.

I will be doing some glaze testing next week, to see which ones are still good and which ones need to be tossed.

 

I have been reading about the processes of flocculation and deflocculation.

 

 

Could someone confirm/clarify for me:

If the glaze is too runny, you flocculate - using epsom salt or vinegar

 

If the glaze is too thick, you deflocculate - using a product called Darvan

 

 

Is this correct?

 

Also, with old glazes that have sat for over a year, and thickened up.... would you toss them or attempt to make them good again?


Thanks for being so respectful and going easy on me with all the newbie questions. This website has been such a fabulous resource!


~* Roxy *~


#2 alabama

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Posted 17 March 2017 - 03:37 AM

While some glazes break down over time, most do not. If it were my glaze, I'd add water stir it up, sieve, and use it on some type of test tile. I've seen where some type of chemicals were used to thicken and thin glazes and wasn't impressed. Just use water.

#3 High Bridge Pottery

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Posted 17 March 2017 - 07:31 AM

 

Could someone confirm/clarify for me:

If the glaze is too runny, you flocculate - using epsom salt or vinegar

 

If the glaze is too thick, you deflocculate - using a product called Darvan

 

 

Is this correct?

 

That's right, a good way to remember is flocks of sheep stay together so flocculation makes stuff thick (charges the particles so they attract each other)


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#4 flowerdry

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Posted 17 March 2017 - 08:34 AM

Agree with Alabama.  Try just using water.  Flocculation of glazes is best saved for those that settle out every time they sit for a while without being stirred and form a hard pan at the bottom.


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#5 Diesel Clay

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Posted 17 March 2017 - 09:51 AM

My first question is, do you have the recipes for the glazes you have just come into? If you don't, you're better off chucking them all, because you won't be able to reproduce the results after you empty the bucket. If you do have the recipes, there's a couple of consider.

I suggest getting them back to workable consistency and testing how they apply before trying to flocculate or de-flocculate.
Even glazes that have been treated with Epsom salts to keep them from hard-panning, or to make glaze application easier, will still settle out if they've been sitting for a year, or if they've been frozen.

If they're solidly hard-panned, trying to re-mix them with a jiffy mixer will actually take you longer. Get a big wire whisk from the restaraunt supply and use that. It's a lot easier to get a wire whisk to the bottom of the hard pan, because you can just wiggle it down to the bottom and shake the lumps into motion again. A jiffy mixer compacts things more with its faster speed. Once you get the stuff loosened off the bottom, you'll need to run it through a sieve to make sure all the ingredients are distributed into a homogeneous mix again. Then you can dip some tiles and see how things go. Once you know how they apply, then you can make decisions about wether or not the glaze needs to be flocculated or not to help with application.

#6 neilestrick

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Posted 17 March 2017 - 10:14 AM

It is extremely rare that you would need to deflocculate a glaze. Usually if it's too thick you just need to add water, which seems to be the case here since they have sat around for a long time. If they settle out too quickly or too hard, then you need to flocculate with epsom salts.


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#7 Marcia Selsor

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Posted 17 March 2017 - 11:10 AM

I'd let the water evaporate off the runny glaze, and add water to the thick glaze.
unless you have a settling problem, add epsom salts.
Marcia
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#8 LinR

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Posted 17 March 2017 - 06:04 PM

A great tool to remix a glaze that has hard panned is a heavy duty loop tool.  L



#9 Stone Spiral

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Posted 20 March 2017 - 09:14 PM

Thanks everybody! This was super helpful!


~* Roxy *~





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