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Vegas Red Glaze Coming Out Transparent


mikenightmare

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I am a high school ceramics teacher (this is my first year doing  ceramics in 6 years after a transfer within my district) so I am relearning everything about ceramcis, and kiln firing is very new for me. The school has a Geil gas kiln. I am (attempting) cone 10 reduction firing and I can not get Vegas Red to come out red. One piece came out transparent (middlish-front of the kiln). There were a couple that were towards the bottom back of the kiln that had some red come out. I am following a schedule I found in a notebook from the previous teacher. It fires around 12 hours.  The glaze is the premixed glaze from aardvark.

 

I hope this is enough information to help me out I am not sure if I am getting into reduction properly or not. Any help would be great, if I need to provide more information please let me know. Like I said this is new for me and trying to figure it all out.

 

Thanks,

 

Michael

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Assuming Vegas Red is a copper red, that white to transparent result generally is a sign of more oxidation during firing and not enough reduction.  Copper reds like reduction; copper reds also fume during firing.  I've had my best results using copper reds on interiors where the fumes tend to keep inside the pot. 

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Thank you for the reply @bciskepottry

 

 

Assuming Vegas Red is a copper red, that white to transparent result generally is a sign of more oxidation during firing and not enough reduction.  Copper reds like reduction; copper reds also fume during firing.  I've had my best results using copper reds on interiors where the fumes tend to keep inside the pot.

 

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Geil is very  helpful to users.  contact them or perhaps Tom Coleman, another in the long list of very helpful people.  the Vegas Red is his formula.  see the 2010 cad discussion re Vegas red and read the comments below the article.  tom answered someone about the firing schedule.

 

where are you?  is there a studio potter nearby whose firing you could watch and learn from?  you do know that you are attempting the most difficult color to achieve.

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Thanks for the tip on the article I found it and his response is helpful on there. I am in so cal. Close to Geil actually. I think I will give it another go with my new info and see what happens then try contacting Geil for some advice. And yes I do know reds are hard to achieve bit I like to challenge myself and figure things out and master difficult task. Hopefully this will be one of them.

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I fired vegas Red in a big old Olsen updraft two years ago when I was teaching at UTB. The kiln was 20+ years old, rusted air

discs on the end of all 14 venturi burners. I followed the previous instructors kiln logs and the kiln fired like a dream.We got reds. As Bciske says, the outer areas of the stacking may not reduce as well.Pack it tight. Also, when doing reds, it is good to start a gentle reduction about ^09 and stay neutral going up. reduce more heavily around 8,9,10. Not necessary for black smoke but it depends on your gas. Natural gases vary quite a lot.You can test for oxygen by holding a stick in front of the peep holes. If they don't burn, you are reducing.Sometimes there is a purple green flame. Just for the sake of the kiln Gods , I would feed small sticks through the peepholes as it started to cool. Maybe a few every 1/2 hour for the first 2 hours of cooling. Just kiln lore but I believe.

 

Marcia

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Copper reds often need to be applied thickly, which can make them run more, so watch out. Keep them away form the burner areas. If they go too hot they will burn out to clear. There is very little copper in the glaze, and it fumes out during the firing. I think you probably reduced fine, because when they oxidize they go green, not clear. Apply thicker, try firing 1/2 cone cooler, and fire faster if possible.

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It's been a while since I've done ^10 reduction, but I definitely agree with the thicker application on copper reds. It makes a huge difference. And yes, they can run too.

 

I've also had really good luck with putting a celadon glaze (or a clear) over copper reds. I'm not sure of the mechanic, maybe it reduces the availability of oxygen to the copper in the copper red, or maybe it's just superstition... But it seemed to work for me before.

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I agree with the thickness of copper red. Here are some Vegas Red pieces from the old Olsen I fired at UTB.There are 4 columns of shelves. This is student work. In the closeup, the pot on the left is stoneware. The pot on the right is porcelain. In the center bottom there are some textured pots which respond well breaking clear on the surface of porcelain. Vegas red is a beautiful glaze when it works.This firing was about 11 hours.You can see two cone packs if you look close. ^10 is standing, ^9 is down. even top and bottom.

 

Marcia

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