Tuesday, December 20, 2011

Blue Underglaze


I'm in search of a dark blue underglaze with good brushability. I want it to behave like ink painting- to be able to dilute to get value & maintain good brushability that is visible when painting on bone dry.
I've tried 2 different shades of Amaco's LUG series, but don't like the consistency, or visibility. I've also tried cobalt oxide with gerstley borate & frit, which brushes better and depth is more visible.
Wondering if anyone has experience with other commercial underglazes or recipes to share?

13 comments:

John Britt said...

I will look for something. I would take a slip (LUG) and then add more cobalt since you seemed to like that. You may also want to add some Mn or Fe to soften it a bit.

Let me look ...

Anonymous said...

Kawai Blue

Fine red clay (I use Redart) 75
Amakusa (I use Cornwall Stone) 25

Cobalt Oxide 1.2
RIO 1.7

Apply thin for bisque under a clear glaze. This is a subdued blue not harsh at all.

Vinod

smartcat said...

I use gerstly borate and frit with my stain or colorant... (I work in majolica) I add glycerin to get a brushablity that is more like ink on paper. That was tip from Linda Arbuckle that has worked well over the years. What temp do you fire at? Depending on the glaze I find that blues in particular run under clear glazes above low temp. It can be lush if planned on.

Newfoundout Potter said...

Hi - I use this slip - 50% spar 50% ball clay and then 2.5% Co and .5% iron oxide. It works on bisque as well as on greenware - use a bit thinner on bisque than on greenware.
Can add more Co to get darker - depends on the thickness of application and on your covering glaze.

Emily J Lees said...

I've had good luck with Amaco's velvets. I use them for everything except black, where I use the LUG.

Emily J Lees said...
This comment has been removed by the author.
John Britt said...

Pottery Making Illustrated (at Highwater) has an article:

33 EPK
33 Frit 3124
33 Stain or oxide

starch.

You may have to tone down the Cobalt.

try it by tablespoon for a start . 1/1/1

Marian Parkes said...

Emily, Coyote makes high fire underglazes and they have several blues. Not sure if they'd work for you. I have some, if you'd like to do some tests. Not sure which colors though... can check after the holidays if you'd like.

http://coyoteclay.com/underglaze.html

Emily Reason said...

thanks all. More testing to do. Britt- the recipe you mentioned...starch? Laundry starch? Is it for brushability?

David Voorhees said...

Emily,
For years I used a painting slip for blues for cone 10 reduction base on Albany slip. If you can find some:
Albany 90
RIO 10
Cobalt Carb. 1
I remember it as being brushable (like 10,000 irises worth), stable and not harsh.
Might be time to try it in the wood kiln...

David Voorhees said...

Emily,
For years I used a painting slip for blues for cone 10 reduction base on Albany slip. If you can find some:
Albany 90
RIO 10
Cobalt Carb. 1
I remember it as being brushable (like 10,000 irises worth), stable and not harsh.
Might be time to try it in the wood kiln...

John Britt said...

Nice David! I have some if you want to try . Also available in CM in the classified or you could just use Alberta.

Emily Reason said...

thanks David I will try it. I actually have some alberta. Hope to post test results ASAP.
So, no gerstley, clay, or gylcerin?