Orion/Baker on sun 8 feb 98
The current dialog about kilns shifting, grinding and spalling themselves
into oblivion is interesting to follow, I must say.
But in all the discussion I've seen on Clayart for quite some time, in the
face of lots of interest in heating and cooling kilns as quickly as
possible, I haven't heard one voice call out for kindness and compassion
for the poor kiln!
The more gently a kiln is heated (whether the refractory is castable, brick
or fiber), the less likely that refractory damage will occur. A lot of the
damage I've heard described lately can be directly attributed to exposure
to extreme atmospheres (salt, sulfur, over-reduction and uncombusted
carbon) AND to heat shock.
If materials have a chance to heat and expand gently and evenly, they'll
certainly last much longer -- and this goes for metal cages and frames,
too. Cranking massive burners up to "vaporize bulldozer" (with or without
turbocharging) may be thrilling, but it's like bungee jumping for bricks!
Whenever I see massive spalling, crusty buildup and surface shrinking, I
can't help but believe that the poor kiln has been "rode hard and put away
wet" (as the cowboys say). I say "be kind to thy kiln" and it should last
a very, very long time.
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