search  current discussion  categories  glazes - ash 

ash glazes/ashpots

updated wed 29 oct 03


Craig Martell on sun 26 oct 03

mel asked:
>could we start a discussion on the merits
>of various ash used for glaze.


The uses and ways to use woodash are as varied as the analyses for wood
ashes in general. That's the great thing about woodash. You can have a
visual dialog using the stuff and articulate things by the way you
understand the many uses and approaches for a material that can give you a
very personal take on glazing in general. Hope that made some sense.

I use a lot of blended ash from the woodstove in my shop. I burn a lot of
oak, maple, fir, and alder. I take it out of the stove and wash it three
times over a period of about 3 weeks, dry it out, sieve it, and make
glazes. Yes, I test it first. If I'm burning a lot of the same types of
wood, I blend the ash through the winter and then test it and make glaze
adjustments if needed.

If I have a lot of a certain kind of wood, I might burn that stuff as solo
as I can and keep the ash pretty pure. I had about 3 cords of black walnut
one winter and got some very nice fine ash from that. It made really nice
celadon ash glazes. These were runners and the rivulets were a nice
green. So, after testing that stuff, I set it aside and didn't do any
blending. I liked what it did and had enough to last a long time. I
heading out next weekend to do a workshop and they want me to mix glazes
and do some glazing so I'm taking some of the black walnut ash for that
gig. We'll see how it goes.

I had some trees come down in the orchard last winter and they were all
cherry trees. Royal Anne, Bing, and another dark cherry. They were very
old, large trees that were at the end of their time. I burned them without
using a lot of hardwood or any other species and blended all the cherry
ash. I have about 30 lbs of that set aside for glazes. The fruitwoods can
yield ash that has a fair amount of phosphorous and they also flux very
vigorously. These ashes make nice rivulet ash glazes and also some very
nice chuns and nukas. I don't get a huge amount of cherry or apple ash so
these glazes don't last forever but it's better to have some than none at
all. With ash glazes, in general, I don't expect to produce any glaze for
years and years without change or variation. That's the way it is and I'm
comfortable with that.

There's been a lot written about ash glazes. If any of you are interested
in pursuing this path, I'd suggest doing some reading and learning about
ash and how it can be used. Then gather a lot of ash any way you can, test
it, make glazes, see how it goes and keep at it. Any source is worth a
go. That reminds me, I need to go up to the Clubhouse and clean out my
mother in laws woodstove. She's been burning fruitwood and oak.

Like Cap'n Mark, the first ash glazes I did were in the electric kiln at
cone 8 and 10 mainly. You can do some very nice ash glazes in an electric
and I don't think it hurts the elements or refractories one little
bit. Anyway, get on it! I want to see what you cats can pull off.

regards, Craig Martell Hopewell, Oregon

mel jacobson on sun 26 oct 03

could we start a discussion on the merits
of various ash used for glaze.

my take is that a good fire place, with mixed
wood ash is a great source.

i do not see why one would order hard wood ash
from a vendor. it seems foolish.

we have gathered ash from our scrap wood fires
at the farm, from the fire places of friends, and
our wood stove.
it is always a mixture, with the bulk being oak and

it would be nice to hear what real ash glaze folks have to
Minnetonka, Minnesota, U.S.A.
web site:
or try:

=?iso-8859-1?q?Marilu=20Tejero?= on sun 26 oct 03

I treasure two of my sculptures fired in the fire box of Robert Barron's multichamber kiln in Gippsland, Vic. Australia. They went in unglazed and the ash of his timber, scraps from a local timberyard, melted into the most luscious glaze.
I am sure the gumtrees did it..!!

Do You Yahoo!?
Todo lo que quieres saber de Estados Unidos, América Latina y el resto del Mundo.
Visíta Yahoo! Noticias.

Hollis Engley on mon 27 oct 03

----- Original Message -----
From: mel jacobson
Sent: Sunday, October 26, 2003 9:32 PM
Subject: ash glazes/ashpots

> could we start a discussion on the merits
> of various ash used for glaze.
> it would be nice to hear what real ash glaze folks have to
> say.
> mel
Mel: I was just in the studio this afternoon going over ash glaze recipes.
The Olympic downdraft I have here has just had its last test-firing and I'm
about to take it to cone 10 with real pots. In a couple of kilns over the
years I've used Phil Rogers' standard ash glaze, which calls for mixed ash.
I have two sources for ash: one is a friend with a fireplace and the other
is my sister-in-law who heats her farm house in NY state with a woodstove.
I don't know exactly what I'm getting from either one, though generally
speaking it's mostly oak or maple. On the farm, there might also be old
softwood planks thrown in, and I find the occasional nail or hinge when I
sift. I sift ash (with a kitchen sifter) from both sources and then I mix
them together. I'll end up with 15 or 20 gallons of sifted ash at a time,
enough to let me be consistent with my glaze over several batches.
At high anagama temperatures, Phil's basic glaze runs a very nice pale
green. (The recipe's in his book, but if anyone wants it I can post it.)
Underfired in the anagama it's matt yellow, which might not sound good but
is actually quite lovely contrasted with brown flame-licked clay and darker
melted fly ash.
In gas reduction, the glaze is green, varies from transparent to matt opaque
depending on temperature, and tends to run a bit. I will often use it at the
top of a vase or tall bowl, dipped over a temmoku or what I call Chun Wen
Red, a high-iron glaze taken from a CM piece seven or eight years ago on the
Taiwanese potter and glaze chemist named Chun Wen. Used over the temmoku or
the iron red the ash glaze runs very nicely in rivulets down over the pot.
I don't know why anyone would buy ash, either, though I suppose if you live
in Florida or similarly warm places there aren't many sources of woodstove
ash. A good source I've noticed around here lately is wood-fired pizza
places. They generate a bucket of ash every couple of days. I haven't made
that contact yet, but I would think that would be a great source.
Hatchville Pottery
Falmouth, Mass.

Norman van der Sluys on tue 28 oct 03

This is a timely discussion for me, as I am just doing some Ian Currie
grids with wood ash from my wood stove. The ashes I'm using are last
years, mixed hardwoods, mostly beech, with a small amount of softwood
from construction scraps. I sieved it and washed it once letting the
ash soak for about 3 days. I dried it and have about 25 lbs processed,
but I have a 15 gallon trash can of the same mix (unwashed) left.

Having heard pros and cons about washing I decided to split the
difference. It is still quite alkaline, but I was worried about the ash
melting at cone 6r as most of what I have read concerns cone 10.

My first grid will be a conservative one subbing ash for whiting - 65
neph sy, 25 wood ash and 10 Gillespie Borate. I'll try Ababi's
suggestion about lithium, too.

Any other suggestions? I've got about a week before i do a glaze kiln
again, longer if it doesn't stop raining. I hate carrying all that
greener 100' through the rain to the kiln :<)

mel jacobson wrote:
> could we start a discussion on the merits
> of various ash used for glaze.
Norman van der Sluys
Benona Pottery
Near the shore of Lake Michigan where the leaves are coming off the