Casting iron

[R.thayer]

I would like to know furance design, fuel, and tools needed to cast iron. I have casted aluminum in an electric kiln. I would like to start casting iron. I would like to cast things like flywheels, cylinders, and bases of engines. Please let me know what your ideas and experiences have been. Thank you

[pfarber]

I'm readinig a lot on furnaces for my first eventual foundery.

You need coke. Hard to get for us small fry... but its essentially a turbocharged charcoal that burns hot enough (with forced air... LOTS of forced air) to melt iron.

Best place (you've probibly heard this already) Lindsey/Gnegerly books.

[jgro]

You can look here also: http://www.rockisland.com/~marshall/index.html

jgro

[sailandoar]

http://www.artfulbodgermetalcasting.com/index.html

http://www.foundry-fopars.co.uk/

http://www.angelfire.com/tx5/hite/furnace.html

[Warpspeed]

Reaching iron melting temperatures is definitely a challenge. Most fuels that just burn openly in air (such as gas or oil) cannot easily reach the flame temperatures required, because of the 80% nitrogen contained in the atmosphere. This vast mass of inert nitrogen does nothing but "air" cool the flame.

There are two technical ways around this problem. Either add extra pure oxygen to displace some (or all) of the nitrogen, or simply preheat the combustion air. Preheating the combustion air will raise the flame temperature by roughly the amount of air preheat supplied.

The traditional way to melt iron is by blowing air through a bed of burning coke. This preheats the air and achieves the sort of combustion temperatures required. But these days coke can be expensive, and pretty well impossible to obtain in some parts of the world.

It is theoretically possible to use either oil or gas to do a similar thing. It requires a heat exchanger. The idea is to use your furnace flue gas to preheat the burner air by several hundred degrees. I was in the process of building a natural gas powered iron melting furnace, but have recently become distracted by the challenge of building my own induction heating furnace.

If the electronic approach does not work for me, I will go back to my original plan of building a natural gas fired iron melting furnace, and continue on with that.

[mattinker]

You might try this group
http://groups.yahoo.com/group/cupola...guid=183173907

Matthew

[yugami]

http://ronreil.abana.org/Furnace.shtml

Propane burner and blower, melts pretty much anything you can think of.

[adamziegler]

I melt iron in about 15 lbs batches with a simple propane furnace. Reaching flames temps to melt iron is not the hard part... light a propane torch and you are already there. The difficulty comes from loosing your heat energy through the exhaust and surrounding air.

At about US$3.50 a square foot you can purchase high temp ceramic blanket that will improve your efficiencies significantly.

As for my furnace... it's a simple fireclay and sand liner. It burns propane and has a blower to supply air. I have some of that insulative blanket (brand name kaowool) sitting in the corner of my garage begging me to build another furnace... CNC project comes first!

[Bluewater34]

The best way that I've found to melt iron is with a cupola. I was fortunate enough to find two Brinkmann's smokers (bar-b-que grills) that had been tossed out due to rust and general wear. They were 14 inches in diameter and in bad shape on the outside. I'll spare you the rest of the construction except to say that I used a greased piece of pvc pipe that was 8+ inches outside diameter, placed it in the middle of each of the barrel sections of the grills. I then bricked one of the sections on the bottom and poured castable that I acquired/borrowed from my employer between the PVC and the metal grill barell... Anyway, I "glued" the top onto the bottom section and had a 40 inch tall cupola with voids around the exterior for the wind box and tuyeres (tweers). You can find most of this in the books mentioned above.

For fuel, I have the luxury of having coke readily available at work, and can bag up some of the fines, accidentally throwing in some nice baseball size lumps. As for charging material, any old gray iron will do, as long as you can bust it up into manageable pieces. With my cupola having an 8" inside diameter, I need small, flat pieces, with the occasional large piece of P & S (plate and structural) tossed in for good measure to prevent bridging. Bridging is either a mere nuisance or a disaster, with a cupola, you need to work fast and do not need to be rodding it out because the iron has melted and bridged/fused above the melt zone. Good P & S may be railroad spikes or tie-plates.

So you will need a blower and a gas supply to heat your furnace prior to charging it. Light off a coke bed at the bottom with some diesel and keep a wind supply on it (try a small electric leaf blower) with the lid off for a good 30 minutes, replacing coke as needed. While you are doing this, you also MUST be heating your ladle. Your ladle needs to be glowing red prior to tapping. Trust me on this. My ladle is simply a refractory lined paint can with rebar T-shaped handles on both sides. You need two people to handle it, the iron is heavy. I keep a piece of kaowool (mentioned above) over the ladle while it is heating.

Once your cupola and ladle are hot, you're ready to charge and melt. You need your charges of both coke and metal bagged in paper sacks, lined up and ready to go. Don't think you have time for this after your first charge.

I'll shut up now. Just a hobby of mine that I really enjoy doing and talking about (obviously).

Blue...

[Ferdinand Galva]

About a year or so I found a file on the web about how to design a cupola furnace and because the lack of information like this, I want to share It with you, please somebody tell me how to upload files.

Regards
Ferdinand

[Ferdinand Galva]

I want to share a file about cupola design I found on the web about a year or so, please somebody tell me how to upload files.

Regards
Ferdinand

[Tailgunner]

After the iron has been cast, how do you have to cool it. I mean, if i cast a large piece of cast (grey) iron that needs to be machined. So I'm looking for a good machinability. I read on I site that they put the piece (after it solidified) back in the furnace with the flame of and let it cool gently inside the furnace. Is this a good approach. After the piece has been machined it will probably be hardened to give it better wear properties, what is the heat treatement for this?