Once firing - underglaze decoration with clear

[KarenB]

Hello All, 

I am just venturing into Once Firing and my pieces are stoneware with underglaze and I'd welcome any advice/insight about covering the underglaze with Cone 6 (zinc free) clear.

Any problems with once firing this combo?
Any adjustments to firing schedule recommended?

Thanks!

KarenB

[George Lewter]

Underglaze should not present any problems. The following might be a good clear for you to try with your UG and clay body.

Recipe Name:  5-6 Clear
Cone:  6     Color:  clearFiring:  Oxidation     Surface:  Glossy
Amount Ingredient

40          Feldspar--Kona F4

30          Gerstley Borate--1999

20          Ball Clay--Old Mine #4

10          Silica

100         Total

This glaze has enough clay to allow it some shrinkage with the body clay.

Kona F4 spar is soon to be extinct, so you might try to buy a full bag if you can get it at all. T

[KarenB]

Thanks for your reply George and for the much appreciated recipe and 'heads up' about Kona F4!
K

[Merry Arttoones, M.F.A>]

Hi....I have tried once firing with satin glazes over my sculptures and vases...because I don't want a glossy finish...I usually get some clouding of the clear satin glaze...which can be a nice effect...but if I want it truly clear and matte to satin...I do my bisque fire all the way up to cone 6 with the underglazes ....and tweek the underglazes again sometimes at a low fire and  and then do a low fire 05/06 satin matte glaze...I should say most of my work is sculptural ...