search  current discussion  categories  kilns & firing - raku 

raku newbie/ glaze problems

updated tue 6 apr 99

 

Charles and Tamara Schulz on sun 4 apr 99

Hi everyone!
I am brand new to raku. I have never seen it but wanted to try my hand at
it. So, I read Steve Branfman's book and watched the beginning raku video
by Gordon Hutchins. With my husbands help, I built a fiber lined oil drum
kiln. we fired it for the first time this weekend. WOW was that fun!!
anyway, I tested several different glazes. some commercial, some of my
recipes and some recipes that I have collected. over all, the results were
very good. lots of amazing, brilliant colors-- EXCEPT for the white crackle
glaze. I tried two different formulas on several pots, in several firings.
Not once did it turn out nice. While the other glazes had a nice smooth,
glossy surface, the white was everything from dry to bumpy to bubbly. I
tried it thick and thin and just couldn't get it right.
Can someone PLEASE shed some light on this for me? Am I under firing? over
firing? I used them on the same pots with various other glazes. and while
they were all beautiful and colorful the whites were just UGLY.
One of the glazes was Gordon Hutchins' matt white from the video. The
other was from "the potter's pallet" by Constant and Ogden. Is anyone
familiar with these glazes or this type of problem?

Also I tried the Pipenburg "alligator" glaze. I have never seen this glaze
before. The color was brilliant but the surface was a bit rough and scaly.
Can I assume from the name that this is correct? Can some one tell me what
to expect from this one? is it best applied thick or thin?

Thanks again to everyone who's kept me afloat so far. Hope you don't mind
bailing me out again!!

Tamara ----in Okinawa-- the cherry blossoms are in full bloom and so is the
rainy season!!!

Frank Bosco on mon 5 apr 99

The white glazes you've chosen e.g., white Matt, and alligator skin,
should be on the dry side judging by their titles. They're probably fine to
use as such, however should be thinly applied.
The temperature range for most raku glazes does not exceed 1940 F. or
cone 04. So if most of your glazes flux out fine except the matte and
alligator, my bet is that the application is too thick.
I have a couple of nice glossy white crackle glazes for you, are you
ready?
Haystack Crackle White
33.9 Custer Feldspar
40.9 Gerstley Borate
14.2 Barium Carb.
11 Flint
100

White Crackle
85 Frit 3110
5 EPKaolin
5 Kona F-4
5 Tin Oxide
100

The magnolia trees, forsythia, and daffodils are blooming here.
Good luck.
Frank Bosco