The Wedging Bat
he wedging bat is a large, thick and heavy slab of plaster used
for various purposes, mainly for wedging (kneading) clay, but also
for drying out slip and other purposes. Why wedge clay? Wedging
helps homogenize the clay and get rid of air pockets. As we would
normally wedge about a pound (half kilo) of clay or more, the wedging
bat should be thick and heavy. Of course the wedging table this
bat rests on should also be very sturdy.
Another use for the wedging bat is for rolling out clay slabs with
a rolling pin. As the plaster absorbs moisture from the clay, it
will separate easily from the plaster surface, in contrast to a
shiny table, to which it would almost certainly stick. Anyone who
has tried rolling out clay on a smooth tabletop will know what I
Plaster wedging bats are also great for drying out recycled clay.
Clay recycled from trimmings can be turned into a slip and then
poured onto the bat. The bat will soak up moisture from the underside.
After a couple of hours, the clay has hardened enough for it to
be flipped over onto the other side, so that side can be dried pout
Now you are ready to mix the plaster. Do this according to the
instructions on the packet, but use a slightly higher plaster-water
ratio (i.e. more plaster). this will ensure you get a dense plaster,
which will be more durable and make for a longer life of the bat.
When the plaster has hardened (give it a couple of hours), remove
it from the frame. Now you can trim the edges with a trimming tool
or a knife. Round them off with a wet sponge. This will ensure that
you don't get bits chipping off the edge and winding up in your
clay. Leave that bat in a warm spot to totally dry oo. When the
clay has dried sufficiently, it can be cut up into bite sized pieces
Making the plaster bat is easy enough. Get hold of four pieces
of wood a bit longer than the size you want your bat to be, and
of a sufficient height. I would recommend about following dimensions:
width 16" (40 cm); depth 24" (60 cm); height 3.5"
(8 cm). Nail the planks together so that you have an open frame
that can be placed on a smooth tabletop. Make sure your table is
level -- check with a water gauge, otherwise your bat will be askew.
(For more info, see also Plaster Bats).
Plug up the gaps between your frame and the table inside and out,
with little rolls of clay (so-called "doggies"), so no
plaster will leak from the frame. ut, e.g. in the vicinity of your
kiln (but not on top! Plaster doesn't like heat above 130o
F/50o C). Due to the size of the bat, this may take a
couple of weeks.
That's it! Happy wedging!