- Someone posted that coal, coke or charcoal could work in a cupola - I disagree. Charcoal may work, but the BTU content is low and ash is high, this reduces your temperature and means you need a massive amount to keep it running, also it is weak and may not support the charges of iron without crushing and choking the blower. Not an experiment I would try. Coal is really dirty stuff and will make bad iron (from sulphur mostly) and ruin the inside of your cupola. Coke is coal with the dirt cooked out which leaves mostly pure carbon and inert ash which comes out the slag hole. The idea of making your own coke is interesting (and possible), but I would stick to trying to find the real stuff. Most of the dirt driven out of the coal is poisonous and/or highly flammable, retriving and sizing the coke would be hard, and it may be poor quality. If you want to run a cupola, find coke - for a small operation it should be quite cheap unless you have to add a lot of freight.
Bob from Memphis
PS Marvin, If it's balanced, it runs clean, but trust me, you can make a cupola smoke like my Daddy's old Ford
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