Dry wood ash on glazes

[Stephen G]

Hello!

New to the site and am curious about the effects of dry wood ash on glazes.

I have found a lot of info about wood ash glazes, but not so much about applying dry wood ash onto an already applied and dried (or sometimes sprayed with a little water) glaze.

I realize glaze recipes will vary greatly so it may not be very helpful to name any, but I have had great results (in my opinion) with the shino glaze at the pottery school I attend, please see the attached image.

I have also tried this on our versions of tenmoku and iron red with results of some fluxing and gold speckling, respectively.

So I suppose my question is what is it in shino glaze that reacts that way with the "freckling", for the lack of a more accurate term? (Perhaps this is carbon trapping? I do experiment with a CTC shino as well.) I'd like to experiment with other glazes and colors, but am curious to know if there is a specific ingredient (or more than one) that I should look for to possibly gauge what the results may be with applied dry wood ash.

Has anyone tried this on, say, a standard celadon or spodumene glaze, if there are such things?

Yes, I am about to do some test tiles, but this will take weeks for results (I am a student so at the mercy of their schedule) so any insight would be greatly appreciated as I could completely avoid any glazes that would have undesirable effect.

 

Thank you so much.

Stephen

[curt]

Hmmm.....

dont know what freckling is...gold specks could be the kind of pyroxene crystals you find in a teadust glaze...

As to what might happen, if, if...well, wood ash is notoriously variable as a glaze ingredient so hard to say anything there.  And how other unspecified glaze ingredients might interact with that mystery ash?  Just an exercise in pure speculation....

You would have more luck finding out how many angels can dance on the head of a pin....

test, test, test....  yes it takes time, and the gains are hard won, but that is just part of the game.  

Good luck!   Would look forward to seeing your results!

[Joseph Fireborn]

I have sprinkled dry ash onto my glazes in cone 6 electric. The results are mixed, it just depends on the glaze and how it reacts to additional flux and silica that the wood ash adds. 

I personally have found better results from making a "paste". I have made a paste out of wood ash. These paste have a slight bit of clay added and a slight amount of a feldspar of some kind, but the majority of the paste is ash(70-90%).  The reason I call it a paste and not a glaze is because it isn't liquid form. I apply it with a natural sponge to the pot by dapping it on. 

 

It looks something like this after being applied. As you can see it is very chunky. I don't sieve the wood ash. I take it directly from my fireplace, put it in a 5 gallon bucket and scoop out the amount I need and add it to a small glaze container. I found that when you sieve the ash and wash it, you might as well just use commercial glaze ingredients. It takes away all the variability. 

The result looks something like this:

A lot of my work is using wood ash paste now as I found applying it this way sort of duplicates the way ash is probably applied in a wood kiln. It isn't a uniform application, it sticks and clumps and builds up in certain places. Again this is all theory as I haven't fired wood before, but I have looked at a lot of wood-fired pots in person and it appears this is what happens.

Of course, I want to say that I am not trying to replicate wood firings at all, but just to get some surfaces that I adore in my electric kiln. There is just something about the randomness of ash that I really appreciate, each tree is unique and thus each batch of ash paste is different.

The pot you posted above is very nice in the glaze and I think the ash definitely did it justice. How was it fired? What kind of kiln?

 

[Stephen G]

Thank you both for the replies.

Yes, Curt, more testing indeed! Was just wondering if anyone has had much experience with this and why results differ greatly with different glazes. It must be something in the chemistry, but I’m not too savvy with that yet so I would need to ask one of the glaze techs or copy the recipe off the barrel, if that would help. And the wood ash bin is a generic mix from someone’s fireplace, I think, which will definitely add some random elements. Test tiles to come...

Joseph, very interesting results! So this is your paste on unglazed bisqueware? Your paste is the glaze, correct? That’s quite a texture, thanks for sharing. I’ve not done a wood firing yet, but have seen some other pieces with very heavy ash fall on them, quite similar. I’m looking for something much more subtle, what you saw from me is my school’s shino glaze on porcelain with a sprinkle of wood ash then fired in cone 10 gas reduction.

Thanks again, looking forward to more feedback, and of course, more testing.

 

 

 

[Joseph Fireborn]

That is the paste, which is technically a glaze, just very pasty instead of wet and fluid. Like if you put your hands in the batch it wouldn't run through your fingers. I don't usually bisque pots unless I am using a particular glaze that I find needs bisque. I single fire almost all my work.

I think you should continue experimenting with the sprinkling stuff. The pot is a real gem.

[Stephen G]

Thanks so much, Joseph, for the clarification... and compliment!

[oldlady]

just a story about ashes.  

i met a woman who had a number of very different pots with beautiful surfaces.  we talked and she explained that they were done with specific ash from specific trees.  each one did something in combination with the base glaze that made that pot different from its neighbors on the shelf.   she had access to a woodworker who gave her the large sawdust from his workshop and identified it for her.  she burned the sawdust and kept the ashes separately.  they really were lovely pots.

that is dedication to ash glazes.

[Stephen G]

Wow, thanks, oldlady.

That certainly is dedication and must be nice to have such resources and a controlled environment. I’m working with what I’ve got, I’ll test the glazes available with the mystery ash at hand first before introducing different types of ash. This could be quite an undertaking!

Any chance this potter is online or perhaps information on her techniques?

[oldlady]

sorry, i met her at a show in the 1980s in new jersey.  i think she lived there and her name began with an "M".   i think she fired in a tunnel kiln.   the pots were beautiful, i remember pots, not so much people.

[tonyp]

The good book Ash Glazes by Phil Rogers, Second Edition has Dick Lehman who sprinkles ash on pots to be fired to cone 9.  It's a small part of the book (2-3 pages) but may be helpful for you, may not.

[Dick White]

I frequently sprinkle ash on the side of mugs glazed in shino. I have a small tub of ordinary unwashed fireplace ash (mixed hardwoods, no pine, pine makes a lousy fire and gunks up the chimney flue) that has been dry seived to 80 mesh, which I use to refill an old spice shaker jar that I keep by the glazing table. When glazing the mugs in shino, I immediately hold the wet glazed mug sideways and shake on a patch of "special spice" ash.

[oldlady]

dick, do you have a photo you could post?

[Dick White]

I don't have my photo cube set up, so here is a thumbnail sketch...

[Benzine]

18 hours ago, Dick White said:

 When glazing the mugs in shino, I immediately hold the wet glazed mug sideways and shake on a patch of "special spice" ash.

11 herbs and spices?

[Dick White]

1 hour ago, Benzine said:

11 herbs and spices?

No, sadly only 10. My shipment from from Dune was hijacked. And besides, like Custer, it ain't what it used to be, so I had to reformulate it.

[Stephen G]

Thanks anyway, oldlady, I thought it may not have been a recent story... but that didn't stop me from Googling a bunch of words you mentioned to see what I could find. Alas, no results.

Thanks, tonyp, I was actually able to find some info on him and actually the exact excerpt from that book! He does basically what I was asking about with the addition of other fluxes on a carbon trap shino glaze and includes that recipe. I'll keep exploring his work, thank you for that.

https://books.google.com/books?id=th3JZzIFFYQC&pg=PA129&lpg=PA129&dq=ash+glaze+dick+lehman&source=bl&ots=iI4qzExKcE&sig=X-zPhr4ywaFcqOsIjZt0AaB-pfI&hl=en&sa=X&ved=0ahUKEwj1lYq_x8faAhUEk1kKHTqoBhk4ChDoAQg3MAM#v=onepage&q=ash glaze dick lehman&f=false

Dick White, yes, this is exactly what I do, thank you for sharing. The spice must flow, indeed! Interesting that it seems to be only shino glaze that people use with wood ash. Is that a spot of iron oxide on your mug as well? What I was initially inquiring about was if there are other glazes that anyone has used with wood ash. Have you? Or is there just something about shino that just works so well?

And I also found out that Simon Leach sprays a liquid wood ash mixture through an atomizer onto unglazed surfaces for a "toasty" look. Funny thing is that I met him at a workshop last year and bought one of his mugs with this effect before I even knew what it was.  The exact mug I have of his is at 6:07 in this video.

https://youtu.be/Co66lGzIMfQ

So I did a dozen test tiles of wood ash on various glazes and one on unglazed bisque, hopefully the results will be ready in a few weeks when the next semester begins. I'll keep you all posted. Thanks again for the replies.

 

[Dick White]

I never tried it with other glazes. It works well with shino, didn't take it further. Maybe something to try? The Simon Leach method of wetting the ash will take you in the direction of washed ash (there is a whole body of knowledge with washed vs. unwashed ash in ash glazes) and the atomizer will give you a finer distribution of the ash on the side of the ware.

And the blue spot is just a finger touch of blue glaze for visual interest.