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Kohaku

Member Since 12 Oct 2012
Offline Last Active Yesterday, 02:56 PM
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Posts I've Made

In Topic: Outdoor Work And Freeze-Thawing

04 September 2014 - 09:54 PM

It a big experiment that may or may not work.May last a winter or 3??? its a big unknown.

(how much degradation is acceptable, and how often you want to replace any given modular piece, some porosity might work. )Was a great statement.

but until you leave it out there you will not know

What I think is the issue is how long you expect it to last VS how long until it degrades.

 

With what I know now about clay- I would want it to last and that means vitrified

anything less is asking for failure sooner than later.

sometimes saying no is best for some opportunities.

 

Your meduim If I recall is Raku and its not made for outside freeze-thaw cycles.

Mark

 

Thanks.

 

I've worked in high fire... although Raku has certainly been dominant of late. For this project, I was considering high-fire elements with small (mosaic tile style) Raku accents. None of the Raku stuff would be structural or sizable.

 

Thanks for the test advice Marcia- I'll do that.

 

I'm thinking that one option may be to craft an external, modular surface skeleton... and then have internal elements (non-structural) made from a porous, filtering clay body.


In Topic: Outdoor Work And Freeze-Thawing

04 September 2014 - 02:39 PM

Water expands as it freezes, so if there are small openings in the clay due to burned out organic matter, that can fill with water, you will get cracking when ice forms. You want a form that cannot harbor water, and won't absorb it either.

 

If it's in a run-off zone, does that mean it will be partially submerged in water? Will the water freeze in winter?

 

There are a couple options. The form(s) could be built on a piling (or other substrate) and be above water. It could be placed in an area that's exposed to storm run-off, but not a perennial channel. Or... it could be placed in a streambed (partially submerged).

 

We're in the 'banana belt' of Idaho here, and surface water typically freezes to about three inches of depth- usually for no more than a few days. So- definite freeze thaw cycles, but only part of the form would be subjected.

 

I've considered other materials (concrete, etc) but the filtrative potential of the form is important, and a porous clay body offers some real advantages if I can get past the freeze-thaw problem. Maybe I just need to do some tests of different sized components...

 

I guess that I could do a modular build, and use non-permeable, fully vitrified components in the areas prone to freezing.


In Topic: Outdoor Work And Freeze-Thawing

04 September 2014 - 12:29 PM

OK- thanks. Just to add a wrinkle to things- what if the piece was rendered permeable through inclusions in the clay?

 

For context, I'm exploring the idea of bio-sculpture (sculptural works that are integrated into natural settings and perform an ecosystem function). Jackie Brookner does this type of work in concrete.

 

Ceramic forms- made from clay bodies with coffee grounds- have been used as bio-filters in some developing countries. I was considering making a form from this type of clay body and installing it in a run-off zone (where it would perform a filtration function, as well as being educational).

 

I could certainly fire the form to full vitrification... but it would still have the inherent porosity. Recipe for disaster? What if the size of individual components was minimized? (Perhaps with a mosaic-style surface over an armature)?

 

I know these are some off-the-wall questions, and I appreciate the feedback.


In Topic: Wood-Fired Turbo Kiln

28 August 2014 - 10:27 AM

Thanks guys. Our group is currently engaged in a pretty intense discussion about what we want here... whether it's simply a platform for hi-fire reduction firing (in which case- maybe we should just invest in a gas kiln) or whether we want to experiment with alternate surfaces.

 

These are really helpful suggestions.


In Topic: Wood-Fired Turbo Kiln

27 August 2014 - 04:15 PM

 

John Theis and Bill VanGilder build a manabigama wood fire kiln. Fires in one day to cone 12 using half cord of wood. Here is link: http://www.monocacyp...com/default.htm

 

If you read the description of the kiln, it ways that only the front portion of the kiln gives heavy ash effects. The back half is used for glazed ware. This is why most tube kilns fire for a long time- it takes a lot of back stoking to build up ash. Just getting to temperature is easy. It takes time to get ash effects. Even train kilns, which are quite efficient by comparison, require 2-3 day firings for the back half to get ash effects.

 

 

This might not be a bad thing, in point of fact... some people might be interested in using the kiln for hi-fire reduction alone.

 

The cross draft kiln you describe sounds like on option we should look into, however.