[TheForge] burning and cracking pots

[Bruce Freeman]

Burning out is due to prolonged overheating.  This can
happen easily with a thin pot, especially if the air
blast is directed toward the walls.  Running the blast
continuously can do this.  For that reason, it is a
good idea to shut off the blast when not actually
heating the metal.  A gate or electrical switch is in
order.  If your pot glows, it's too hot.

Liquid water hitting a hot pot can cause the pot to
crack.  I don't know whether this is the cause of all
such cracking.  I like to sprinkle water on a
bituminous coal fire, both to dampen the coal and to
control the fire.  I teach that this should ONLY be
done by sprinkling, not pouring, and ONLY when the
blast is on.  The hot blast tends to evaporate the
liquid water, preventing contact with the pot, but you
can defeat that by applying too much water.  I've
never seen a sprinkling can I really like.  The ideal
would be a can you could lift over the fire, then
apply the water.  A metal garden sprinking would be
good if it were of smaller capacity (a cup, not a
gallon) and were on a long handle.

You are MUCH more likely to crack a thin pot than a
thick one.  A steel pot is more forgiving, even if
thin, but will deform much more readily than cast
iron.  Steel can take higher temperature than cast
iron  without melting, but usually that's not the
concern.

I suspect that ALL thin cast-iron pots were  intended
to be clay-lined, and burn out principally when not. 
(Castable refractory is a readily available, modern
alternative to clay.)  Unfortunately, clinker sticks
to clay or other refractories.  

Bruce
NJ

--- Lynn and Susan Lang <langfarm at together.net> wrote:

> Hello
> Parts of this discussion have mentioned firepots
> "wearing out" or
> "cracking".
> I have been led to believe that the use of water on
> the fire as the
> cause of this destruction.
> How does water factor into the longevity or lack of
> the pots life?
> Thank you
> lynn
> 
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