search  current discussion  categories  glazes - crazing & crackle 

white crackle raku secrets?

updated wed 15 dec 99

 

Malone & Dean McRaine on thu 9 dec 99

I've just finished a month of raku firing. One of my projects was the
search for a great white crackle glaze. By great I mean a bright white
glaze with big dark lines, evenly spaced, 1/4" to 1/2" apart with the
unglazed areas a deep black. I failed, I tried 5 different promising
recipes. I reduced some immediately out of the kiln, others I let cool
until I could hear the glaze start to crack. I tried moderate reduction
with leaves and ultra-heavy reduction by burying the piece with sawdust. A
few pieces were OK with strong but finely spaced irregular patterns, most
sucked, some really sucked-pinholed gray glaze with faint gray cracks and
soot I couldn't scrub off with cleanser. One of the refired pieces was
decent. They're in the trash now. I've seen enough nice crackle whites to
know that there must be a way and it can't be that hard. There's some
surfers with a studio in Maui that are using a really nice brilliant white
crackle/deep black and I don't think any of them have a degree from Alfred,
if you know what I mean.. I was using Laguna's S-60 clay firing to 1850F.
Anybody have any thoughts on this?.
Thanks,
Dean

Karen Shapiro on fri 10 dec 99

Hi Dean,

Here's my favorite white crackle raku glaze:

FATTY WHITE
frit 3134 80
ball clay 9
silica 9
zircopax 10

Pull slowly, leave out a few seconds before placing in reduction can (you can
also use a fan to get good crackles before reducing). Another trick for
darker cracks is to open up the can after a few minutes and add more
reduction material to get more carbon in the cracks.
I too am always looking for THE white crackle; so far I like this one the
best.

You also might want to change clays -- there is a big difference in the
crackling. Don't know what kind of work you do -- I sculpt and use either
Sonora White by Aardvark or Raku Sculpture by Claymaker.

Karen in Sonoma

Toni De Lisa on fri 10 dec 99

Dean,

What kind of clay are you using? Stoneware? A raku body? What color is
your clay body? White clay with a porc. slip will take care of the bright
white question. Choosing the right reduction materials will help in keeping
things white and easy to clean off. I've found that shredded office paper
works best. (Know any lawyers? ) The deepness of the black portions and
cracks will be determined by how well your reduction is. As for your wanting
quarter inch spaced cracks..............I've never been interested in
controlling the process that much. I do know, however, that I have the best
results if I open the kiln and let the piece stand for a couple of minutes
before setting it in the pit.. Gives the glaze a chance to harden , which
keeps clean up to a minimum. I reduce for 20 minutes or so and once the piece
is brought out, it helps to have someone assist you. Spray water on the
piece......hard!........while someone else fans it. Try playing with the
water pressure, timing and blown air. No secrets, honey. Trial and error.
If you would like, I will send you my glaze formula.

Toni

Raku Boy on fri 10 dec 99


I haven't tried this and have only a little white crackle experience
- but does india ink work for filling in cracks like regular low fire
crackle? Or is that cheating? Just wondering - as for the bright white I'm
not sure.

- John Christensen


>----------------------------Original message----------------------------
>I've just finished a month of raku firing. One of my projects was the
>search for a great white crackle glaze. By great I mean a bright white
>glaze with big dark lines, evenly spaced, 1/4" to 1/2" apart with the
>unglazed areas a deep black. I failed, I tried 5 different promising
>recipes. I reduced some immediately out of the kiln, others I let cool
>until I could hear the glaze start to crack. I tried moderate reduction
>with leaves and ultra-heavy reduction by burying the piece with sawdust. A
>few pieces were OK with strong but finely spaced irregular patterns, most
>sucked, some really sucked-pinholed gray glaze with faint gray cracks and
>soot I couldn't scrub off with cleanser. One of the refired pieces was
>decent. They're in the trash now. I've seen enough nice crackle whites to
>know that there must be a way and it can't be that hard. There's some
>surfers with a studio in Maui that are using a really nice brilliant white
>crackle/deep black and I don't think any of them have a degree from Alfred,
>if you know what I mean.. I was using Laguna's S-60 clay firing to 1850F.
>Anybody have any thoughts on this?.
>Thanks,
>Dean

______________________________________________________
Get Your Private, Free Email at http://www.hotmail.com

Richard Jeffery on fri 10 dec 99

Dean

I don't think this is the answer, but do you spray your pieces with water as
they come out of the kiln? The white glaze I use needs to fire a bit higher
than the other colours - I was finding that it was going too hot into the
reduction. If heavily covered by sawdust, I rarely got a decent crackle -
it was as if the sawdust was insulating the piece, allowing the glaze to
cool slowly.

I found that spraying gently twixt kiln and can started off a decent
cracking. You do need to get the spray right - too heavy, you get grey
spots where the glaze cools right down, too dense a spray and you get a very
fine crackle. I use a cheap garden spray.

I've another problem now - biscuit firing cooling down, preview on Saturday,
it's raining like crazy and there's another storm coming in tomorrow. When
do I get to do the glaze firing?

Regards

Richard
Bournemouth UK

> -----Original Message-----
> From: Ceramic Arts Discussion List
> [mailto:CLAYART@LSV.UKY.EDU]On Behalf
> Of Malone & Dean McRaine
> Sent: 09 December 1999 16:25
> To: CLAYART@LSV.UKY.EDU
> Subject: White Crackle Raku Secrets?
>
>
> ----------------------------Original
> message----------------------------
> I've just finished a month of raku firing. One of my projects was the
> search for a great white crackle glaze. By great I mean a
> bright white
> glaze with big dark lines, evenly spaced, 1/4" to 1/2" apart with the
> unglazed areas a deep black. I failed, I tried 5 different promising
> recipes. I reduced some immediately out of the kiln, others
> I let cool
> until I could hear the glaze start to crack. I tried
> moderate reduction
> with leaves and ultra-heavy reduction by burying the piece
> with sawdust. A
> few pieces were OK with strong but finely spaced irregular
> patterns, most
> sucked, some really sucked-pinholed gray glaze with faint
> gray cracks and
> soot I couldn't scrub off with cleanser. One of the refired
> pieces was
> decent. They're in the trash now. I've seen enough nice
> crackle whites to
> know that there must be a way and it can't be that hard. There's some
> surfers with a studio in Maui that are using a really nice
> brilliant white
> crackle/deep black and I don't think any of them have a
> degree from Alfred,
> if you know what I mean.. I was using Laguna's S-60 clay
> firing to 1850F.
> Anybody have any thoughts on this?.
> Thanks,
> Dean
>

Bob Wicks on fri 10 dec 99

Dean:
You did not mention how many coats of Raku glaze you applied to your
projects. In my humble thinking you might have better luck if you used a
thicker coating of glaze. This should accent the crackle. Try it and I
would be interested in how it works for you.

Good luck
. Bob

Karen Broderick on sat 11 dec 99

HI there Dean,
In our studio we use Robert Piepenburg's white crackle
and when we fire it we bring it up to at least 1900F to 2000F
and we look in to see if it looks shiny and fluxing ... we also
have sprayed it onto pieces and the crackles are further apart
and it is turns out really white white when it is used on B-Mix
lol ... it also helps that we have Robert as our professor
Good Luck and Happy Holidays ... karen

Pamala Browne on sat 11 dec 99

HELLO DEAN IN SEARCH OF BRIGHT WHITE CRACKLE--- SOME TIME AGO I POSTED A
WHITE CRACKLE THAT WAS WORKING VERY WHITE FOR ME.MY LAST FIRING WAS
DISAPPOINTING ,HOWEVER ( GOT A REAL PRETTY PINK ON JSRH). MY FRIEND HOWEVER
GOT THE BRIGHTEST WHITE BIG CRACKLE IN THE SAME FIRING !! SO ,,,,HERE IS
WHAT HE USED----------- 60% COLEMANITE 40%NEPH SY 9%ZIRCOPAX.
SAME AS MINE , BUT HE ADDED 5% MORE ZIRCO. HE WAS USING IT ON RED CLAY SO
I -KNOW- IT WILL GO VERY WHITE. MY EXPERIENCE HAS BEEN THAT WHITE CRACKLE
HAS TO GO UP A LITTLE HIGHER THAN OTHER GLAZES THAT I USE. THAT MAY BE THE
REASON FOR THE PINHOLES. SOMEONE ELSE MAY KNOW MORE ABOUT THAT. BEST OF
LUCK------------- pamalab
----- Original Message -----
From: Malone & Dean McRaine
To:
Sent: Thursday, December 09, 1999 8:24 AM
Subject: White Crackle Raku Secrets?


> ----------------------------Original message----------------------------
> I've just finished a month of raku firing. One of my projects was the
> search for a great white crackle glaze. By great I mean a bright white
> glaze with big dark lines, evenly spaced, 1/4" to 1/2" apart with the
> unglazed areas a deep black. I failed, I tried 5 different promising
> recipes. I reduced some immediately out of the kiln, others I let cool
> until I could hear the glaze start to crack. I tried moderate reduction
> with leaves and ultra-heavy reduction by burying the piece with sawdust. A
> few pieces were OK with strong but finely spaced irregular patterns, most
> sucked, some really sucked-pinholed gray glaze with faint gray cracks and
> soot I couldn't scrub off with cleanser. One of the refired pieces was
> decent. They're in the trash now. I've seen enough nice crackle whites
to
> know that there must be a way and it can't be that hard. There's some
> surfers with a studio in Maui that are using a really nice brilliant white
> crackle/deep black and I don't think any of them have a degree from
Alfred,
> if you know what I mean.. I was using Laguna's S-60 clay firing to 1850F.
> Anybody have any thoughts on this?.
> Thanks,
> Dean
>

Diane Karmiol on sun 12 dec 99

I have been cheating with Duncan CR-800 clear crackle cone 06 and using india
ink. Looks really cool but I get very fine crackle. Would love to find recipe
for 06 or 6 clear or white crackle that will give large (raku) type pattern.
Any suggestions?
TIA Diane in Miami

Mike Gordon on sun 12 dec 99

Hi,
I have used ink in my clear glaze over B-mix with good results. I always
seal the inside with some type of sealer though - water will seep
through a low fire glaze and spread the ink. Always tell buyers what it
is. that the secret. Mike

Nancy Guido on sun 12 dec 99

Shhhh! Don't tell anybody. I make a raku tile out of white crackle and use
latex resist for a dancer in the middle. If it re-oxidizes and doesn't come
out good and black....I use black paint like Liquitex, and ...promise not to
tell? I also have a copper colored marker by Berol Prismacolor for
touch-ups. Shhhh. Liquitex also makes a copper metallic paint. I have some
of that too, but don't tell, it's my secret.

Nancy

Mike Gordon on mon 13 dec 99

Hi,
Try Duncan Diamond Clear C/06 ox. on Laguna's B-Mix then ink. Try
reheating it and spray with water too. Looks great. Smooth as a baby;s
butt. Mike

Vicki Ferris on mon 13 dec 99

Recently, I tried a ^10 sculpture clay, which I bisque at ^04. I found that I
got better crackling on the sculpture clay than the other raku clay I was
using. I use both clays now and use 4 white crackle glazes. Sometimes I was
not getting a true black on unglazed areas, kinda dark grey. I found that
using a seperate reduction container is doing a much better job. I am using
the large can that popcorn comes in at this time of year. The reduction is
much better. When I use my galvanized tub and put 4 to 5 vases in it,
sometimes the reduction is not as good maybe due to the extra time of putting
each piece in the tub and then closing the lid. Too much newspaper and
sawdust seems to burn away before the last vase is put in. By using the
single container, and closing the lid quickly, seems to give brighter lusters
and very black clay where unglazed. Hope this helps you.

Vicki in Cool, CA

ababy sharon on tue 14 dec 99

Once I saw in a lecture a slide of piece:Part of it was made out of claybody
that 20% of it was bentonite.In the firing that part shrun, and looked like
crackled
glaze.Since than, this idea does not leave me! In my last raku firing I
tested a glaze 20% bentonite+80% frit,( similar to 3110), I got crackles but
not better that any other
raku glaze.May be using bentonite can help, I will try again may be this
time
with more bentonite.
Ababi

----- Original Message -----
From: Diane Karmiol
To:
Sent: Sunday, December 12, 1999 06:23
Subject: Re: White Crackle Raku Secrets?


> ----------------------------Original message----------------------------
> I have been cheating with Duncan CR-800 clear crackle cone 06 and using
india
> ink. Looks really cool but I get very fine crackle. Would love to find
recipe
> for 06 or 6 clear or white crackle that will give large (raku) type
pattern.
> Any suggestions?
> TIA Diane in Miami
>