There are two types of kilns, brick and ceramic muffle. Mine
is a muffle. Muffle kilns heat up faster than the brick type and can easily be
moved from classroom to classroom without damaging the kiln. Its best to not
move the brick type kiln because, movement can cause the bricks to become loose
since they are held together with mortar.
Over time the muffle can develop cracks. I've been told that
the cracks shown here in my kiln were caused by opening the door while the kiln
is very hot. I'm guilty of this, due to opening the door while enameling. These
types of cracks are not harmful. As long as the muffle isn't breaking apart in
pieces, and the elements are still secure inside the muffle. As the muffle
heats up it expands and the cracks close.
You should occasionally inspect your kiln by checking the
thermocouple in the back of the kiln making sure it sticks out from the back of
the kiln about 1/2". It can sometimes inadvertently get pushed into the
muffle. The thermocouple measures the kiln's temperature and sends this
information to the kiln's computer. If it is pushed into the muffle it can't
accurately measure the temperature inside the kiln.
If you are having problems with melting your metal clay
while firing, then you should test the thermocouple for accuracy with a kiln
tester. Here is a link to my instructions on testing the thermocouple:
Testing Kiln.
Sometimes the door's latch needs adjusting. The latch should
lightly catch so that it doesn't shake the kiln. The door doesn't need to close
tightly against the front of the kiln. There needs to be some space for the
door's material to expand when it heats. If you work with enamels, you don't
want the door to shake the kiln when closing otherwise you may find your enamel
has fallen off your piece! On my kiln the door latch adjusts by twisting a
screw in or out on the latch.
It’s also good to check the kiln's plug wires making sure
they are not cracked or damaged. If they are seek advice from a kiln
repair company.
