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Ashes on glaze


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#1 gypsy

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Posted 12 April 2013 - 05:16 PM

What would happen if I sprinkle woodstove ashes on wet glaze. Would the piece run or do nothing? Thanks

#2 mregecko

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Posted 12 April 2013 - 06:52 PM

I used to do this a lot when I had access to a ^10 rx kiln. It usually produces runny spots of a different color than the base glaze (it alters the glaze chemistry upon fluxing). It's definitely possible for it to cause glaze run-off, but if you use it strategically (I did a lot of "thumb print" spots of ash) it can create some beautiful effects.

I'm sure other community members can explain the chemistry of what happens much better than I can. But these were my observed results.

Also note, if you're doing this in an oxidation environment (like an electric kiln), make sure that you have adequate ventilation. It will probably produce ash / smoke blowoff, like firing any organic material will.

Cheers!

#3 Biglou13

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Posted 12 April 2013 - 08:08 PM

Good question seeing how I just ran a few test pieces...

Fired to cone 6 ox. Electric.

The ash I used is is mostly oak (so I was told)

The pieces were glazed, then sprayed with water, ashes (unwashed) applied to wet area.

Well the results were quite boring no runs no color change, the areas look like the glaze never quite got glassy :( , immature glaze?

Glaze was version of a cherry blossom shino. Which is from 33 tried an true glazes.

They are going to get refired but I'm not holding my breath.

I'm a newB, so I hope one of the gurus will shed some light on the subject.

I ill post pics next time I'm at studio.
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#4 gypsy

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Posted 12 April 2013 - 08:53 PM

Good question seeing how I just ran a few test pieces...

Fired to cone 6 ox. Electric.

The ash I used is is mostly oak (so I was told)

The pieces were glazed, then sprayed with water, ashes (unwashed) applied to wet area.

Well the results were quite boring no runs no color change, the areas look like the glaze never quite got glassy Posted Image , immature glaze?

Glaze was version of a cherry blossom shino. Which is from 33 tried an true glazes.

They are going to get refired but I'm not holding my breath.

I'm a newB, so I hope one of the gurus will shed some light on the subject.



I ill post pics next time I'm at studio.


Thanks everyone for the info.

#5 neilestrick

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Posted 13 April 2013 - 11:25 AM

Ash on glaze will respond much better at cone 10. At cone 6 it does not flux out nearly as much. You may want to try cutting it with a small amount of soda ash, neph sye, or borate frit. Test, test, test.....
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#6 gypsy

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Posted 13 April 2013 - 11:37 AM

Ash on glaze will respond much better at cone 10. At cone 6 it does not flux out nearly as much. You may want to try cutting it with a small amount of soda ash, neph sye, or borate frit. Test, test, test.....


Thank you

#7 mregecko

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Posted 14 April 2013 - 12:15 PM

Good question seeing how I just ran a few test pieces...

Fired to cone 6 ox. Electric.

The ash I used is is mostly oak (so I was told)

The pieces were glazed, then sprayed with water, ashes (unwashed) applied to wet area.

Well the results were quite boring no runs no color change, the areas look like the glaze never quite got glassy :(/> , immature glaze?

Glaze was version of a cherry blossom shino. Which is from 33 tried an true glazes.

They are going to get refired but I'm not holding my breath.

I'm a newB, so I hope one of the gurus will shed some light on the subject.

I ill post pics next time I'm at studio.


Just curious here too... Every cherry blossom shino recipe I've seen is for a reduction kiln (as true shinos are). What are you getting at ^6 ox with the glaze?

#8 AtomicAxe

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Posted 14 April 2013 - 03:07 PM

Ash on glaze will respond much better at cone 10. At cone 6 it does not flux out nearly as much. You may want to try cutting it with a small amount of soda ash, neph sye, or borate frit. Test, test, test.....


This.

At ^6 ash will remain crusty but will flux together. A normal mixer for straight ash at ^6 in my studio is borax and gerstley borate ussually in a 3 to 1 ratio of ash to flux ... also a dash of whiting if intended for functional ware to help resist scratching. other additions of clay and flint will let it be a normal glaze, so layering is more subtle but not needed unless it's a stand alone glaze.

Just did this recently for some bowls ... standard stuff, since it's really just flux with impurities it will effect your glazes in different ways. one is a iron rutile glaze, fluxed over to create the amber rim to chocolate pool in the middle of the bowl. Other is a very stable copper matt glaze so it resists over fluxing and will bead like a regular ash glaze.

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#9 Claypple

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Posted 14 April 2013 - 04:00 PM

Super!

#10 Biglou13

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Posted 15 April 2013 - 09:49 AM


Ash on glaze will respond much better at cone 10. At cone 6 it does not flux out nearly as much. You may want to try cutting it with a small amount of soda ash, neph sye, or borate frit. Test, test, test.....


This.

At ^6 ash will remain crusty but will flux together. A normal mixer for straight ash at ^6 in my studio is borax and gerstley borate ussually in a 3 to 1 ratio of ash to flux ... also a dash of whiting if intended for functional ware to help resist scratching. other additions of clay and flint will let it be a normal glaze, so layering is more subtle but not needed unless it's a stand alone glaze.

Just did this recently for some bowls ... standard stuff, since it's really just flux with impurities it will effect your glazes in different ways. one is a iron rutile glaze, fluxed over to create the amber rim to chocolate pool in the middle of the bowl. Other is a very stable copper matt glaze so it resists over fluxing and will bead like a regular ash glaze.


Can u clarify what kind if ash, washed or not? How much borax : gerstly borate? are you firing 6^ ox?

I have some neph Sy on hand Start 3 :1 ?

I also imagine runs will be better served on glaze other than white , the runs would be more dramatic.

How did you apply ash. It is quite messy.

In assuming at ^6 ox ash will create runs only, but at higher^ and redux ...color?

Would Ferro frit. 3134 serve well in fluxing ash? Is 3:1 good start?

Do you "sift" the dry ingredients together then apply?
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#11 Biglou13

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Posted 15 April 2013 - 10:59 AM

[/quote]

Just curious here too... Every cherry blossom shino recipe I've seen is for a reduction kiln (as true shinos are). What are you getting at ^6 ox with the glaze?
[/quote]

It's a clean pin hole orange peel . With this body. Which I love. Picture is brush test of glaze .

It smoother and flesh/ peach with laguna 900. I'm also very happy with this , and some craze to boot. Gunomi /shotglass. I was wondering why it was called "cherry....." Until now since glaze has no color. And until this piece just white.

(Apologies to original post if this is too far off topic)

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#12 AtomicAxe

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Posted 16 April 2013 - 12:48 AM

Currently I fire to ^6 ox, and all my ash is unwashed ... washed ash is a waste of time. (At least for me) The idea in the 3 to 1 ratio of ash to low fire flux is to move the melting point down to get the ash to do its ash awesomeness so you can tweak as needed. I prefer gerstley borate and FF 3134 as they are borosilicate fluxes which have a negative glaze expansion rate which means less chance of surface crazing as the glaze surface cools and contracts ... neph sy does not have that key component for that but will work. borax is water soluble and not ideal due to its rather unstable nature but will work in a pinch. Simple though, as I just scoop out what I need from my bins ... when I need a more reliable mix, I will mix a complete glaze by weight.

this is my formula for a complete glaze and a good start

Ash 50
FF 3134 20
Flint 15
Kaolin 10
Whiting 5

That fits most needs. some variations on this is my high iron version

Ash 60
FF 3134 15
Redart 15
Flint 5
whiting 5

Decent enough as a tob glaze, stable by itself and good in combo with other ash glazes.
Another is Val Cushings ash ... simple and nice ... little on the matte side but has lovely rivulets and takes to colorants well.

Ash 50
Gerstley 20
Whiting 12
EPK 8
Silica 10

And when I started switching to ^6 firings my original recipe was

Ash 60
Gerstley 20
EPK 20
Silica 20

Not 100% I know ... went more for a ratio formula by weight than 100% calculation ... might notice it ... 3/1/1/1 highly glossy, some surface crazing due to high flux high silica ratio but bonds with glaze body well.

In the past I would have one base that had 5% zircopax, 5% rutile and 1% cobalt which would result in a milky blue glaze with white highlights on the top that would flow with the rivulets. would then top that with the 3 to 1 ratio blend with a heavy cobalt mix on top to make that dark cobalt fade from top to bottom with a partial dip and a stable liner glaze inside of functional ware.

oh, and 5% yellow ochre works well in ash especially with other iron bearing glazes.

Found that straight ash glazing doesn't sell in this area (too georgia rustic for texans) so I go for a more subtle approach and that is ash as an accent on glazes to change the surface.

#13 weeble

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Posted 16 April 2013 - 12:54 AM

I have been using a mix of unwashed pellet stove ash and terra sig every now and then, and its an interesting textural finish. Areas where its REALLY thick don't flux and just fall off as soon as you hit it with water, but the ash/sig mix itself fluxes slightly and sticks nicely. It sort of glops on as you brush it, but it does flux enough to give you a really nice decorative glaze. I have put other glazes on the rims of some of these pots and the glaze moves a LOT more than normal, but I haven't tried putting the ash/sig mix over a glaze.

https://sphotos-a.xx...153309217_n.jpg

This one is a tan clay, stained with iron oxide then wiped off the high points. Then a layer of ash/sig mix (I use dry ash and add enough white terra sig to make it brushable) brushed over the sides, and a green matte glaze on the very rim with occasional drips down the side.
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#14 Biglou13

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Posted 16 April 2013 - 09:01 AM

Ty for all the info. It will come in handy. I'm learning a lot about making glazes.

But back to original post intent............

Is it possible to add DRY ASH ...........?

Since we need to lower the melting point of ash........will a dry application of Ash ,and FF 3134. Work?

I've seen where artist will spray bottle water onto a piece then apply ash to outside of piece to get that ash runny goodness ( however it was higher fired)?

(Fact is .....I need to start building my glaze ingredient library)
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The beige is blinding!!!!!!
The middle of the road is boring

The true sign of intelligence is not knowledge but imagination.
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#15 Biglou13

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Posted 16 April 2013 - 09:03 AM

Ty for all the info. It will come in handy. I'm learning a lot about making glazes.

But back to original post intent............

Is it possible to add DRY ASH ...........?

Since we need to lower the melting point of ash........will a dry application of Ash ,and FF 3134. Work?

I've seen where artist will spray bottle water onto a piece then apply ash to outside of piece to get that ash runny goodness ( however it was higher fired)?

(Fact is .....I need to start building my glaze ingredient library)
Caution big brother is watching.
The beige is blinding!!!!!!
The middle of the road is boring

The true sign of intelligence is not knowledge but imagination.
-Albert Einstein

#16 neilestrick

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Posted 16 April 2013 - 09:24 AM

You can sift ash onto a piece. I think a dry mix with frit is worth a try. Dry mix it really well first, of course.
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#17 AtomicAxe

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Posted 16 April 2013 - 11:24 AM

You can sift ash onto a piece. I think a dry mix with frit is worth a try. Dry mix it really well first, of course.


+1

Should work since it sticks to the glaze as a whole. might make it spotty since the particles themselves aren't sticking together.

If just dry mixing doesn't work, I would wet mix ... really just to thick slip consistancy, let dry, then break up back into a powder. the smaller contained mix should be a blend at that point of everything in the right consistancy if all else fails.

#18 neilestrick

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Posted 16 April 2013 - 01:33 PM


You can sift ash onto a piece. I think a dry mix with frit is worth a try. Dry mix it really well first, of course.


If just dry mixing doesn't work, I would wet mix ... really just to thick slip consistancy, let dry, then break up back into a powder.


I like this idea a lot. Maybe hit it with the blender when wet. Remember that wet wood ash is caustic, so wear skin and eye protection when handling.
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