タイトルまたは説明

Cast iron has been used in banya furnaces from ancient times. Cast-iron cannon balls were used in order to get steam in the field and thus the expression cannon-ball steam was born.
Heat capacity of cast iron is *0% higher than that of stone and heat conductivity is *0 times higher. Thats why cast-iron balls will warm the entire stone furnace (and hence the whole steam room) several times faster.
Cast-iron balls do not crack and go to pieces under abrupt temperature changes.
Why is it not advisable to use only cast-iron balls to fill the whole stone furnace? The steam you get from cast iron is very dry and hot. In order to keep humidity balance and get comfortable, soft, health-improving steam you should use a mixture of cast-iron balls and stones to fill the furnace.