Until (jusqu'à ce que)

When you want to say that an action will continue "until" a specific outcome is reached, use the conjunction jusqu'à ce que.

Because the outcome is anticipated but hasn't actually happened yet, jusqu'à ce que must always be followed by a verb in the subjunctive mood. (Note that que contracts to qu' before a vowel or mute h).

He is going to shape the clay until it is perfect.
Il va modeler l'argile jusqu'à ce qu'elle soit parfaite.
Stay until the pottery hardens.
Reste jusqu'à ce que la poterie durcisse.
We are waiting until the ceramic hardens.
Nous attendons jusqu'à ce que la céramique durcisse.

Whether you are waiting for a kiln to cool down (refroidisse) or clay to become supple (devienne), the rule remains the same:

Leave the kiln closed until it cools down.
Laisse le four fermé jusqu'à ce qu'il refroidisse.
Add water until the clay becomes supple.
Ajoutez de l'eau jusqu'à ce que l'argile devienne souple.