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Glaze Run


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Hi 

 

Thank you for replying. Actually, I already have the recipes, but not that style.

The glazes I attached is very thick, matt, and looks partial. My own is very fluid and gloss. 

My assumptions are the glazes must be low in china clay and high active flux like feldspar, whiting, iron oxide and zinc oxide.

I wish the others can add the solutions.

 

Thank you

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I think it is probably done at the glazing stage than the firing stage. I would try dipping a pot in a glaze that stays fluid/wet for a while and flip it the right way up quickly to get some drips running. Then maybe a little extra added to the drops.

 

It doesn't look too matt in the picture but it is very small.

 

Any glaze that is running that far from a straight line would in my opinion run all the way to the bottom and it's a stiff glaze made to look runny/drippy/fluid.

 

After going to their website and looking at a few I have changed my mind, they certainly look runny and they call them runny glazes but still not that matt. I remember somebody trying this by just adding a really thick glaze at the top that fell off the pot onto the shelf.

 

If you want runny glazes the number one way is to lower the alumina, alumina acts like a spider grabbing onto the silica chains as they flow past slowing the speed.

 

gallery_23281_871_31544.png

 

Source - https://books.google.co.uk/books?id=cUwwoR-RuJ0C&pg=PA309&lpg=PA309&dq=alumina+spider+glaze&source=bl&ots=GPqulHG-Hd&sig=tG_fcIeFNx2DqPWF8pu3616OOyw&hl=en&sa=X&ved=0ahUKEwjLj46Nq_3LAhWGXCwKHWoNC40Q6AEIIjAB#v=onepage&q&f=false

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I saw a pot like this recently at NCECA. Different colour but same kind of run pattern and big drops. It was a very stiff glaze, and I happen to know it was cooked for a very LONG time (15 to 20 hour soak).

 

looks like some high surface tension going on in this glaze, particularly those big, bulgey, spherical-looking drips. In other contexts we would call this crawling but here it is pleasing and somewhat more controlled, which makes me think it is produced by longer than usual firing, rather than a glaze which is going to crawl in an uncontrolled manner.

 

I agree with High Bridge that high aluminium is a likely suspect here, and high Magnesium may also be contributing. For a good read see Hamer and Hamer on Surface Tension (Joel do you have this book yet??)

 

Not saying there are not other ways to get it, though. But you may try upping alumina or magnesium or lengthening soak time or both.

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I was actually saying to lower alumina to make it runny but if you are going the 15 hour hold route then need some high alumina :D

 

I was thinking maybe it is a long soak to get the drips but never put those thoughts down. Always more than one way to the end. The reason I thought it was unrunny glaze made to look runny was because of the big drips and how much they are raised up from the pot.

 

Still not bought the book but I might have a good look for it today as I finally have a little spare moolar.

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i do not know ANYTHING about glaze chemistry but i got big drips like that when i used a Fake ash glaze for the first (and only) time.  nothing special was done to the pot, a vase about 8-9 inches tall sprayed white glaze and the top part dipped in the  fake ash.  sold so no picture unless it is among the hundreds somewhere in the pictures program.

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Hmmm, yes I have used ash glaze plenty but to my mind that is different to what is going on in Nata's pot.   Ash glazes (or fake ash - same mechanism) makes long, straight-ish runs which seem to keep going and going until they run off the pot or simply run out of juice and stop.  In either case the drop at the end is not nearly as big and spherical as what we are seeing above.

 

Cant rule out that how the glaze was applied could have had something to do with it, but that would be very difficult to control I think!  Maybe someone who has specifically gone after crawly glazes can weigh in?   

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One thing catches my eye about the sample pic: there is a very distinct line between the Lt. rose and the Lt. Blue glazes. So that makes me wonder if the the Lt blue is slightly over fluxed to make it run. Then it runs onto the Lt. Rose which has added alumina.  In reality, the glaze run is not extensive compared to others I have seen. The glaze run actually is balling up: which makes me think there is a rapid change in viscosity. I do believe calcium would have that quick reaction. Joel, as you said: someone has played with/ran tests on for awhile. The Lt blue is semi gloss, and the Lt. rose is very matte: which added alumina would explain some of that.

Nerd

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My first thought, and then I waited to see what the rest of you said, was that it was a slip/clay drip/blob, covered with a stiff glaze.  I couldn't do anything that accurate, but I don't see why it couldn't be done that way.

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