Engobe on bone dry ware

[Nicky S]

Hi ...... Have some porcelaine cups that have reached the bone dry stage .Am wondering if I can still use engobes or slip on them before bisque firing ? Also can engobes or slip be  used on bisque ware ? and then does one glaze as usual ?

Thankyou Nicky 

[Min]

There is often some difference in peoples definition of a slip versus an engobe. Part of my definition between the two is a slip contains more raw clay than an engobe and therefore a slip will shrink more than an engobe. Since your cups are now at the bone dry stage I definitely wouldn't use a slip, it will shrink more than the cups during firing and probably crack or shell off. An engobe would be a possiblity, but they have to be made to fit the body they are going on. Easiest option would be to use an underglaze. They can go on dry greenware or bisque. You can either bisque fire the underglaze on when applied to greenware or bisque or glaze over an unfired underglaze on bisque. The latter method can have glaze absorption issues as underglazes contain binders that can impede glaze application.

[Nicky S]

Thank @Min

Greatly appreciate your info and input Have nothing to loose as I don’t want them plain So will try underglaze and engobes And see what happens Nicky :-)

[Chilly]

On 8/12/2020 at 5:28 PM, Min said:

I definitely wouldn't use a slip

Agree with this.  I know it, I've read it. I tried it.

What happened?  It cracked and fell off before it was even properly dry.

Sometimes we can only learn for ourselves!