WORKING WITH SLABS
Rolling a Slab
1) work on a dry absorbent surface and use a dry wooden rolling pin (it's handy to have two boards and two rolling pins if rolling larger slabs).
2) handle the slab carefully with the flats of your hands to avoid stretching
3) after the final roll leave the slab in place to dry to stop curling
To build with soft slabs you may want to allow the slab to dry for 30- 90 minutes, so that it's easier to handle.
For working with hard slabs it will take 6-20hrs depending on temperature, the clay needs to be firm but still very damp.
If you're not ready to work with your slab once it reaches the correct state it can be wrapped in plastic.
Constructing with slabs
When joining hard clay use vinegar slip/slurry (see video on main tutorial page) and score the surfaces to be joined deeply, so that the slip really sinks in. Clay shrinks by up to 30% as it dries and this, as well as firing, puts a lot of stress on joins, they need to be well 'glued' together.
When joining hard clay use vinegar slip/slurry (see video below) and deep scoring. This is by no means always necessary, when joining soft clay slip made with water will suffice and if you're joining very soft clay you may not need slip at all. But if in doubt there is no harm using vinegar slip. Clay shrinks by up to 30% as it dries and this, as well as firing, puts a lot of stress on joins.
Finishing with a Surform
You can remove as much as needed with a surform when work still contains moisture (ensure you clean tools and surfaces with water after to minimise clay dust, which is dangerous to enhale).
Final Finishing with a Sponge
This is a really important stage for acheiving a 'professional' finish (if you want a smooth neat finish of course)