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I Forge Iron

What metals can a coal fire melt

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I have done some amount of small aluminium castings using a welded steel ladle in my forge and recently was able to buy for next to no money a small lot of commercial foundry tools. Graphite crucibles, pouring shanks and steel flasks. Also got a lid off a crucible furnace. Apparently the rest of it had been destroyed in a transporting accident but the lid is in good condition.

The two significant things about this is that I now have crucibles that can take cast iron temperatures and the pouring shanks aren't built to be used on a forge but a furnace that sits on the ground. So to use them I need to make a dedicated furnace.

I was thinking an old propane bottle that I have with an air pipe in the bottom and the top cut off and replaced with the commercial furnace lid. Basicly just a really deep forge. I don't have easy access to commercial foundry cement so I was going to line it with a small amount of clay and see how well it goes. 


My curiosity that I wanted to ask here is that does anyone know how hot coal can get a crucible to? I have lost a fair amount of small items in the forge and found them later as a little steel blob. Would it be possible to melt cast iron in small amounts?



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Please look up a cupola furnace where you melt up to tons of cast iron using coke and air.  You might want to check how Huntsman used to melt steel back in the early industrial revolution.  If you have the correct refractories and PPE you can melt steel and cast iron using coke/coal. 

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The issue is the amount of fuel needed to bring a material up to pouring temp.  As the pouring temp goes higher, losses from the furnace also increase dramatically (and not in a linear fashion) so doing the higher temp stuff requires a LOT more fuel than lower temp stuff.  It usually becomes inefficient and costly to do something like steel except on a lark.  Brass is probably the highest pouring temp material that might be in the realm of practical for a home-brew system.

Just because it's possible doesn't make it practical.


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