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Pugaboo

Accidentally Left My Plugs Out... My Reds Look Fabulous

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Last time I fired a load of glazed stuff I forgot until the last hour of the program to put my plugs in. I was worried I would have ruined everything but instead anything that had red on it came out really bright and beautiful.

 

WHY? Was it the additional oxygen? the slightly slower firing cycle as the kiln had to to work harder to get to temp? Just dumb luck?

 

To duplicate this again do I have to leave the plugs out until the last hour again or is there a certain period of time that works the magic with the Reds?

 

T

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Well, there is that story, of the potter years ago, who couldn't replicate a beautiful red color, the local ruler really liked. In frustration he threw himself, into the firing kiln, the result was a beautiful red, due to the reduction he caused.

 

So what I'm saying is, who or what fell in your kiln Pugaboo?

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You can just duplicate what you did with plugs out for the hour or run a few tests with different amounts of time, maybe starting with plugs out for 45 minutes first, then 30 minutes the next time until you get those same results.

 

Paul

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What cone do you fire at?  My professor was working with brightly colored low fire glazes and always left the plugs out he said it made all of the colors brighter. Denice

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Hey everyone thanks for the input. I was away for the day doing a festival, in answer to your questions:

 

I am firing cone 6 electric with a downdraft vent.

I used a commercial glaze, Coyote Really Red. It's a nice red but this time it came out ripe tomato red, it practically glows. Its a nice mid tone red that I use on the outside of my spoonrests and on the inside of some of my boxes but it's not generally a juicy ripe red.

I left the plugs out for 7 hours of an 8 our program cycle.

The cycle was not that much longer than usual even with the missing plugs I don't have my notebook here for the exact difference but maybe an hour longer than usual? I would have thought it would have taken much longer to reach temp with all the plugs out.

I cooled it at the same rate as usual which is basically leave it on its own until around 300 then pull the plugs until 200 then prop the lid then when I can't wait any longer opening it when it gets somewhere between 150-175.

 

Oh and I counted all the Pugs and still have 5 running around here so none of them crawled inside, but if a nasty slithery thing crawled in there and gave its life for glorious Reds I might just have to get me a snake catcher and do it again.

 

I will try and photograph 2 pieces one with plugs and one without to show you all. I have 2 large orders to get out by Wednesday and still have almost 5 dozen boxes to transfer fire and about 2 dozen spoonrests so be patient it might not be until the end of the week.

 

Thanks again everyone!

 

T

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I would think that putting the plugs in only at the last hour, after a slower climb in oxidation, might have created a reduction atmosphere. Not sure if that was as beneficial to your glaze results as leaving out the plugs for the full firing (as Denice's professor opines) would be. If your glazes are not intended for reduction and still came out better, the plugs in at the last hour probably only speeded up the slower firing without contributing to the red's brightness. Can you afford a couple of test firings to find out?

 

The quest for redder reds can become all-consuming - I've told that "despairing potter" story many times, but don't tell it to your pugs!

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I would think that putting the plugs in only at the last hour, after a slower climb in oxidation, might have created a reduction atmosphere. 

 

Rae, could you elaborate on your thought here?

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I'm willing to believe in almost anything influencing a copper-red glaze. However I see that Cyote Really Red

is based on a Cadmium inclusion stain.

http://www.sheffield-pottery.com/COYOTE-GLAZE-REALLY-RED-PINT-p/cg071p.htm

 

... which AFAIK are supposed to be pretty insensitive to firing conditions.

 

Maybe Denice's prof had it right, and the glaze surrounding the stain is brighter?

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I would think that putting the plugs in only at the last hour, after a slower climb in oxidation, might have created a reduction atmosphere.

 

Rae, could you elaborate on your thought here?

Reducing the amount of oxygen available to the glaze, which induces red from copper, not sure about cadmium.

Leaving the plugs in for the cooling to slow it could've helped too.

 

I'd say do it again the same way. If your results are the same, you can consider whether you want to mess with success. If not, play with the variables.

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For copper reds to work, they must be oxidized on the way up, then the red forms as they cool. Leaving peep holes plugged would create very little reduction, definitely not enough to make a copper red.

 

Most all commercial cone 6 red glazes are either using a red inclusion pigment, or are some form of a chrome-tin pink.

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For copper reds to work, they must be oxidized on the way up, then the red forms as they cool. Leaving peep holes plugged would create very little reduction, definitely not enough to make a copper red.

 

Most all commercial cone 6 red glazes are either using a red inclusion pigment, or are some form of a chrome-tin pink.

Ok, thanks. I'm most familiar with gas.

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