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Low Fire Glazes- Raku Firing- Reliable Color


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#1 Kohaku

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Posted 01 October 2013 - 05:39 PM

I've been working in Raku for years now... always with glazes I've made from scratch (culling shamelessly from Gary Ferguson with some variation).

 

I'm interested in expanding into a set of glazes that mature at raku temperatures... but that aren't sensitive to the reduction/oxidation continuum.

 

I'm assuming that such glazes exist... probably built around Mason stains or the like? This is pretty far off the reservation for me though. Any recommendations? I'm happy to buy the glazes pre-made in this instance, since I'd be using them chiefly for accent work.

 

Ideally, I'd like surface that was glossy but opaque (enamel-esque) with a range of color options.


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#2 Bob Coyle

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Posted 01 October 2013 - 06:41 PM

Just as a start you might try adding some colorants to the white crackle glaze you probably use.

#3 Kohaku

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Posted 01 October 2013 - 06:53 PM

Just as a start you might try adding some colorants to the white crackle glaze you probably use.

 

I've thought about this... but that particular glaze is pretty translucent. Ideally, I'd like something a bit more opaque.

 

Also... sad (and maybe naive) to say, but I'm sort of hoping to cut corners and not do a ton of testing on this one.


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#4 JBaymore

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Posted 02 October 2013 - 09:33 AM

Check out Steven Branfman's work.  He uses LOTS of commercial low fire glazes.

 

best,

 

......................john


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#5 Kohaku

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Posted 02 October 2013 - 09:52 AM

Check out Steven Branfman's work.  He uses LOTS of commercial low fire glazes.

 

best,

 

......................john

 

I have Steven's book- it's been an excellent resource.

 

He's got some general commentary about commercial vs. recipe-based glazing. However, what I'm still unsure about is the reaction of commercial glazes to reduction conditions. For instance- some of Duncan's envision series seem to have the characterstics I'm looking for. However- let's say I bought some of the Turquoise. Is it a copper-based glaze that would flash red (and everything between) in a reduction atmosphere... or is it built around stains that will retain the stock color?

 

I've emailed the company... but I thought some of you sages might know...


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#6 Kohaku

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Posted 10 October 2013 - 10:59 AM

Update...

 

I've had lengthy conversations now with technical staff from both Duncan and Amaco. In neither case was a provided a clear answer to my basic question- 'does your cone 06 glaze hold color across a range of oxidation/reduction conditions'.

 

Duncan refered me to one of their 'Potter ambassadors'... who has used the Envision line successfully in Raku. Even she noted that the color-fastness varied from glaze to glaze.

 

So... it's off to the test kiln I go, with a cross section of 06 glazes in my arsenal. I'll post the results if anyone's interested.


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#7 JBaymore

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Posted 10 October 2013 - 03:37 PM

I feel your pain.  In the past I've had to deal with the "technical staff" at XXXXXXXXX to find out some straighforward info about one of their products.  Had to go thru multiple layers heading "up the chain of command" before I found someone who actually had a techincal clue.  I finally just asked for one of the ceramic engineers on their staff... if they had one.  It took that to finally get to someone who knew more about techincal ceramics than I did.  Pain in the butt to get accurate answers.

 

Oh... and that person totally contridicted the "information" that I kept getting from ALL the lower down folks.  180 degree opposite information.  And backed it up with information so that I knew HE was right and all the others WERE wrong.

 

Most folks would have likely stopped with the first level of "technical staff".... and gotten totally wrong information.  Caveat emptor with ALL suppliers. 

 

And remember that the supplier / manufacturers do NOT indemnify you from liability with using their products.  You are responsible for testing if the product is suitable for the uses you put it to on YOUR products (for which you are liable).

 

best,

 

...............john


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Professor of Ceramics; New Hampshire Insitute of Art

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#8 Marcia Selsor

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Posted 10 October 2013 - 05:43 PM

Way back when in the 80s Kurt Weiser and Ralph Esposito in Helena Mt. were using commercial glazes fired to ^04 and then fired in the raku kiln to a lower temperature of ^06.. By doing this the commercial glazes don't change and are not changed by oxidation nor reduction.These were not raku glazes. raku glazes, if used , were added for the raku firing. Commercial reds stayed red.

Marcia




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