How to pour cast iron in home foundry?

I don't think you can get enough heat with a simple burner. I think you have to trap the exhaust gas from the furnace and use it to pre-heat the inlet air to the burner. We have a guy with a very sophisticated furnace here, and he couldn't even get enough heat to even melt bronze with it. When he opens the furnace, the top of the crucible is just barely orange, the rest of the crucible is red, although a "bright" red. You need to get the CONTENTS of the crucible white hot to melt cast iron. The crucible will be so hot the radiation will burn you without extensive protective gear.
Jon

Depending on what kinf o burner you have its entirely possible to melt cast iron in the back yard type foundry furnace. I would not recomend it if you used home brew refractory, as its too undependable, but I routinley do cast iron melts for some stuff that needs to be cast iron and not alum or bronzes without a problem. I use a modified Monster burner, and 3200 castable refractory. 3200 deg ref is not a necessity , but when you get it for free why not use it..
I buiilt a small coupla and it was more of a hassle than it was worth just for a small ocassional pour of cast iron.....May e fine for larger pours but I certianly did not need anayhting any larger than my furnace already provided.
I've been pouring aluminum and brass for years, using natural gas or propane fired melt furnaces. Now, I want to try some small cast-iron pours - say under 5 pounds. Any words of wisdom from the group? Building a cupola is a last resort. TIA, Dave.

I think that fellow needs to rethink the meaning of sophisticated then if melting bronze is not doable. Even the mediocre homebrew refractory furnaces and plumbing fitting burners readily melt bronzes......And most of them can do cast iron if their refractopry would hold up.........
David Anders> I've been pouring aluminum and brass for years, using natural gas or propane I don't think you can get enough heat with a simple burner. I think you have to trap the exhaust gas from the furnace and use it to pre-heat the inlet air to the burner. We have a guy with a very sophisticated furnace here, and he couldn't even get enough heat to even melt bronze with it. When he opens the furnace, the top of the crucible is just barely orange, the rest of the crucible is red, although a "bright" red. You need to get the CONTENTS of the crucible white hot to melt cast iron. The crucible will be so hot the radiation will burn you without extensive protective gear.
Jon

From a cost consideration, a cupola may be your first choice. A shop vac, some small size drain culvert or two 30 gallon steel drums, fire clay/brick and a littel welding are all you need. You can even put wheels on it and make it portable.
Chastain's foundry books are the best money you will ever spend see Navy foundry manual is basic reference. see My only problem is not spending all my money on books so I don't have enough for the furnace .....
Uncle George
See

C.W. Ammen, who wrote several foundry how-to books including one about how to pour cast iron, recommended breaking up the scrap iron into small pieces and packing them into a crucible between layers of charcoal or coke. He said that this is a simple way to melt iron in small quantities in an ordinary crucible furnace.
Mike

Well, his furnace is sized for aluminum, and holds a 30 pound crucible. It is built in a 55 gal. drum. I suspect he could get higher temperature with some careful tuning of the air/fuel mix. He probably has too much air flow, to heat that huge crucible quickly. But, bringing cold air into the burner lowers the peak temperature.
Jon

Move your home into a commercial foundry.

Thanks for some new ideas - but nobody mentioned MIFCO (McEnglevan gas-fired melters Models B series etc that will melt aluminum, brass or grey iron up to Class 30 or 35). Very nice, with all controls such as ultra-violet flame failure cutoff and electronic spark ignition, but a bit pricey. I was hoping someone in this group had built a homemade unit and would share their experience. Maybe a small cupola is the best way after all. Thanks, Dave
Building

How many products can you count which are highly sophisticated but suck for their intended purpose? I see a lot.
Chris