Furnace

[wierdscience]

Coke situation is okay we are about four hours from Birmingham,Al still lots of foundrys there coke goes for about.10cents a pound which works out to $10.00 a charge the single biggest obstacle we have had is locating the fireclay like looking for hens teeth.We finally found and old timer around here who told us that we were sitting right on top of some in our back yards told us to dig down about six feet and we would find a white/red clay with lots of feldspar in it he even told us how to mix and ram it in the furnace.

[Rich Carlstedt]

My friend and I built a cupula years ago .
I am not familiar with Chastains book, so don't know how much he says, but we had a heck ov a time getting started, UNTIL a real metalergist who worked for a Iron Foundry came to help..

Here are some comments.
You must preheat the air blast .our early cupula didn't use a wrap around air preheater, and we were "cooling" the melt.
Our unit was 10 inches by 20 high.
remember ..Preheat, Preheat, preheat, the air
He said the air needs to be at 2700 +deg for proper reduction when it enters the cupula!

We used "silver coke"...great stuff

Do not use lime stone, or if you must, only a little. We charged with fist size chunks of broken flywheels from a local farm repair shop. great metal to use as it is clean!
do not use radiators or window weights.
limestone is for pig iron and plugs up the cupula .

Keep several spare "Plugs' for closing up after a tap.

Get some "Hot Shot".This is some metal pieces like pills and you put a couple in the crucible before a tap. When the hot iron hits the pills, an "exothermic" reaction takes place and the melt INCREASES in temp so you have more pour time.

Vanadium additive helps machining a great deal..get some and add to the cruciable

Safety is LAW
When you see a fist size chunk of iron melt like butter in under 5 minites....you know you have heat! and Danger.

Do not allow your feet to be anywhere spilled iron can each.
We used a Kids sand box (but we had no kids )next to thee cupula and all pours were over the contained area.

For you guys that have not been near a ciupla under blast, the heat burned off my hair when I was 5 feet away, so you must lower the blast when checking the Twiers

Good Luck

do they tell you about wedges ? to see how hard (chilled) the iron is ???

[wierdscience]

Steve's design uses a wind ring around the waist of the furnace with one blower inlet feeding all four tuyeres,He also has a chapter on using down commers to boost air inlet temps and a chapter on oxygen inrichment to make cast steel(should be interesting). As for puoring we intend to run our moulds under the tap hole (after the first tap has been pulled off and dicarded) on a set of long roller tables,to keep crucible time to a minimum,I guess you could call it a pseudo production method.As for flux the most common method around here is to use ground clam shells as you can grind them up real fine and they are a lot softer than limestone.

[This message has been edited by wierdscience (edited 03-15-2003).]

[Rich Carlstedt]

Sounds like you got it, but make sure your molds are big enough. When that iron comes out, it isn't so easy to stop. thats why I said to have extra clay plugs.

Have Fun , and the 10 X 20 size was inside dims!
rich

[ibewgypsie]

How about a tilting cupola, I saw one once in a website that tilted. Would cutting off the blow and tilting it up cut the flow? or would it freeze? would you tilt it and leave the blow on? that would burn out any objects in the spout? cause it would have the least resistance :ie no coke several feet on it?
I want to build one here, I have a aluminum furnace waiting on more time to complete. I am using a 1/4 din temp controller with thermocouple and blower control. I hope to make adequate dies here for casting motorcycle parts. I am torn between charcoal and propane as a heat source.
ALL the books say to start with aluminum to learn all the saftey tips. It melts out about 1200 if I remember correctly, as opposed to the 3800 I kinda remember on steel-iron.

[docsteve66]

Little hick school i went to had a couse in foundry where we melted cast, rammed molds etc. I THINK they advised having a place to pour any excess. I say it would be good advice for a beginner- I had trouble even as a young man getting my plug in a hot hole.