Interesting cupola video

I found this interesting video which shows a lot of methods not commonly used.
1. The cupola tilts to drain the iron into a ladle.
2. The ladle is made from a lightweight material like ceramic fiber.
3. Ceramic shell molds are rarely used with cast iron.

 

There are several things in the video that I have not seen at the local cupola iron pours.

I was told by the local iron folks that the scrap iron had to be broken up into pieces smaller than an entire brake rotor, or else the entire melt could go solid, and indeed Clarke saw a cupola go solid at Tannehill due to that.
They had to use an oxygen lance to clean it out.

Feeding entire brake rotors obviously works for them in the video, but I would assume an entire break rotor would almost block the air flow. Seeing is believing though.
I will have to show Clarke (Windyhill Foundry) this.

I have never seen a tilting cupola, and am not sure of the advantage of that.
The cupola designs I have seen all have a sloping floor, and so the metal runs out on its own without needing to tilt the furnace.
Seems like you are creating a design to solve a problem that you don't have.
There must be some logic to their method though.

The ceramic fiber ladle is commonly used around here, and the are lightweight, and seem to be quite insulating.
The local folks often stand around for minutes once the metal is in the ladle, and they don't seem to be in any hurry at all.
And then they go on to pour numerous molds with a two-person ladle, which takes several minutes, and the metal shows no signs of going cool.
I think iron in a ceramic ladle will stay at pour temperature easily for five minutes.

Another benefit of the ceramic fiber ladle is that they don't seem to radiate much heat, unlike a crucible full of iron, and so are more comfortable to be around when the pouring is going on.

I did not even know you could pour cast iron into a ceramic shell mold until DavidF did it, and I would not have thought to try it.
DavidF made some lost PLA parts that have better surface finish, very tight tolerances, and drill easily regardless of how thin they are (he sent me some, and I tested them).

David's thread is around here somewhere.
I can't find his thread, but I did filtch some of his photos, which are shown below.
I would not have believed the quality had he not mailed me the pieces.

He really got die-cast quality castings using the shell process.
The only imperfections in the cast parts are due to the shell process exactly mirroring/copying the imperfections in the 3D prints.

 

When I first started looking at melting iron, I guess in 2011, I bought a cupola book, and was all excited about building one.
I started looking for a source for coke, and realized I had wasted my money on the cupola book because I could not find a source for coke.

So I turned to using an oil burner, and have never looked back.

So last week, I was visiting my sister and brother in law, and my sister said "my granddaughter just got a job at a company in Alabama".
I said "really !, those companies all seem to be in the coke businesses", and she said "yeah, she works for xyz Coke" (or whatever it is called).

She would probably have to work there a while in order to get in a position to get a relative some coke.

The local Metal Museum has a coke source in Alabama, but they are a non-profit art group, and the coke people seem to cater to them and to the school-related art-iron groups.

At this point, I think I could get a pickuptruck load of coke from someone in the art-iron community, but the problem is that handling and transporting the stuff is difficult, time consuming, and that translates to expensive.

Its so simple for me to drive to the gas station that is one block from my house and fill up however many diesel tanks I want to fill up.
With diesel readily available everywhere, I seldom stock more than 20-30 gallons at at time.

Its just so simple to melt with diesel.
If I wanted to upsize my furnace, I would use two burners at 180 degrees.
Justin was using I think a #70 crucible with a single oil burner without problems.

I think with two standard siphon or pressure nozzle burners operating at 3 gal/hr each, in an 180 degree configuration, you could use a huge crucible, perhaps twice as large as what Justin was using.
I have a crane and a pouring cart with large wheels, so pouring 200 lbs of iron is no problem at all.
With a heavy-duty pouring cart, you could pour who knows how much iron.
I have been told that there are one-man foundries out there that pour tons of metal; its entirely possible.

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Those turned out absolutely amazing with an almost unbelieveable surface finish. Here's a couple of shots of a spare that was left over. Glad I have it, I don't think we found the ones I sent, so I will need it when the chair gets here sometime this year to finally finish the repair.

 

The tilting cupola is a very clever idea, if I were to build another cupola I would make it tilting. Looking at the video when there are two brake rotors that have just been put in side by side I would say this cupola would be 450mm to 500mm in dia. (18'' to 20") so it would not need to cut up into smaller pieces. Hmmm two burners trying to melt iron in a crucible that is twice the size of Justins, some how I don't think it will happen.

 

I think the idea of tapping the melt at the bottom is to avoid the slag coming out the tap hole. The typical cupola tap hole is at the bottom of the pool for a reason.
The local Metal Museum has a slag hole at the top of the melt, and if you used that, you would just tilt all the slag off the melt into your ladle first.
I don't see any wisdom in a ladle full of slag.

Seems like an exotic and radical idea right?
Wrong, just look in the MIFCO catalog.
Why would you think it would not happen?
Perhaps you are saying it would not happen in a backyard setting?

I think Clarke is headed that way, and I have no doubt he has the talent to pull that off.
It is well within the realm of backyard folks, and is just a sized up typical oil-burning furnace; the design is well documented.

The furnace would not even be that expensive to make.
The crane and pouring cart would cost more than the furnace build.

I would use dual variable-speed Toro leaf blowers.

MIFCO B2001:
Dual Burners @ 180 degrees.
Crucible Size Range: 150 - 225
Iron Capacity: about 650 lbs
Interior Dimensions: 23" diameter, 25" deep

 

Morgan makes a Salamander Super A-shape up to a #200, which is approaching 500 lbs of iron, and a #400 bilge with about a 1,000 lb iron capacity.

The dimensions of a Morgan A-200 are 19.3" tall, 15.75" top outside diameter, and 11.2" bottom outside diameter, almost 500 lbs iron capacity.

A better selection would be the Morgan #200 bilge, which is 15" top diameter, 20" tall, 12" bottom, 16" bilge diameter, almost 600 lb iron capacity.

If you built the interior of the furnace slightly taller, say 28", then I think you could use a #300 bilge, which is 17" top dia, 22.5" tall, 13" bottom dia, 18" dia bilge, almost 900 lbs iron capacity.

If you are going to build a furnace with a 23" diameter, then it would make sense to add a few inches in height so you could use a #300 bilge if desired.

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I saw a photo or video of someone pouring with a large crucible at an art-iron show.
I will have to find that and post it.
It was a whopper as I recall, I think crane mounted.

Here are photos from a pour at Carrie (not my photos, and I don't recall who to credit them to; Jammer perhaps?)
This was a ladle, but if you can handle a ladle this size, then with a heat shield, you could also handle a #300 crucible, which would be much smaller than this ladle.






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The art-iron community has some rather massive cupolas in the states.
Go BIG or go home, as they say.

I think Clarke took these photos, and they actually use this cupola at a university (forgot which one).

You would have to be careful where you stand when they are dumping this one.

There is talk of an upcoming iron pour with this cupola.

 

Here is another one of Clarke's photos of an art-iron pour (somewhere).

The ladles are the high-temperature ceramic-fiber type.

 

DavidF: Seems like alot of iron for the interior dimensions???

A #200 crucible is roughly 12" diameter (average), and 19" tall,
so pi are squared, times height equals volume.

(6" x 6" x 3.14) = 1132 sq.in.

(113 sq.in) x 19" = 2147 cu.in

iron weighs about 0.29 lb/cubic inch

(0.29 x 2147) = 623 lbs. iron

Iron is rather dense stuff.

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If I were building a furnace that size, I would go ahead and make it 24" diameter, 28" tall, and set it up to take a #300 bilge, and thus you would have almost 900 lbs iron capacity for a slightly larger furnace and crucible.

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Here is a cupola section, and you can see the slag hole at the top of the melt, and the tap at the bottom.

 

Its 15" diameter at the top, 12" diameter at the bottom, and 16" diameter at the bilge point, so I picked a nominal 12" diameter, which is actually smaller than the average diameter of a #200 bilge, so that would account for any wall thickness.

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From the Morgan catalog for Salamander Super Bilge crucibles.
Last column on the right is pounds of brass capacity, which is slightly higher than the equivalent volume of iron, but close.