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powdered underglazes


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#1 Elizabeth 2

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Posted 13 May 2013 - 02:32 PM

Does anyone have any tips for mixing under glazes in powder form with something which will keep them suspended rather than settling out within a day? Any ideas for a suspension agent that will help? If you buy the ready mixed ones they don't settle out so there must be something that is added. I would much appreciate any comments.

#2 OffCenter

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Posted 13 May 2013 - 03:48 PM

Does anyone have any tips for mixing under glazes in powder form with something which will keep them suspended rather than settling out within a day? Any ideas for a suspension agent that will help? If you buy the ready mixed ones they don't settle out so there must be something that is added. I would much appreciate any comments.


There are other things you can do but probably the quickest and easiest is to add ~2% Bentonite and/or a pinch of Epsom Salt.

Jim
E pur si muove.

"But it does move," said Galileo under his breath.

#3 Doulla

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Posted 13 May 2013 - 04:37 PM

Does anyone have any tips for mixing under glazes in powder form with something which will keep them suspended rather than settling out within a day? Any ideas for a suspension agent that will help? If you buy the ready mixed ones they don't settle out so there must be something that is added. I would much appreciate any comments.



I buy an underglaze medium which comes in liquid form (I'm in the UK so maybe this is called something else in USA) which I add to the underglaze powder and water which gives the same consistency as the ready mixed ones. It took me a while until I discovered this and struggled for a long time with just the powder and water.

#4 Min

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Posted 13 May 2013 - 05:02 PM

From Spectrum site, the first product is to add stains to, would that work? first on the following link:

http://www.spectrumg...com/miscpg.html

I would guess other suppliers have a similar product if Spectrum isn't available by you. I think it contains a colloid which keeps everything dispersed evenly. They also have a brushing medium which I would assume is just a CMC solution.

Min

#5 Elizabeth 2

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Posted 14 May 2013 - 09:39 AM


Does anyone have any tips for mixing under glazes in powder form with something which will keep them suspended rather than settling out within a day? Any ideas for a suspension agent that will help? If you buy the ready mixed ones they don't settle out so there must be something that is added. I would much appreciate any comments.


There are other things you can do but probably the quickest and easiest is to add ~2% Bentonite and/or a pinch of Epsom Salt.

Jim



#6 Elizabeth 2

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Posted 14 May 2013 - 09:41 AM

Thank you both for the suggestions. I had wondered about bentonite and will give it a try but also like the idea from Doulla and I can probably get some bought out to me [I am in southern Spain]

#7 perkolator

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Posted 14 May 2013 - 11:43 AM

CMC gum solution. Many commercial glaze companies use a fair amount of this in their products as well as other gums/bentonite/hectorite, etc to help with suspension and brushability. It will help with suspension similar to bentonite and epsom salts (and you can even use both/all) -- but an additional benefit is that when it dries, the CMC forms a sort of "hard shell/candy coating" similar to that of dried snot/snail trail - it sounds gross, but when dry it will help keep the glaze where you put it and be more abrasion resistant to your hands or additional brushwork before being fired. It also helps the material to "flow" and be more brushable.




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