Interesting cupola video

Discussion in 'Furnaces and their construction' started by Ironsides, Jan 30, 2020.

  1. PatJ

    PatJ Silver

    A bilge #200 holds almost double that.

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  2. PatJ

    PatJ Silver

    I think 3" clear all around would be sufficient for oil burners.
    That amount of clearance has always worked well in the past.

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  3. OMM

    OMM Silver

    The A200 holds 31.88 L at brim full. This equals 1945"³. 1945"³ x 0.2833333 lbs./"³ = 551 pounds is my guess.
    30B003B5-BF62-4B94-9857-ED04B192502A.jpeg
     
    Last edited: Feb 2, 2020
  4. PatJ

    PatJ Silver

    A 24" diameter furnace would give you 4" clear on either side of a #200 bilge, at its widest point, and it would give you 3" clear on either side of a #300 at its widest point.

    You would have plenty of combustion space with a 24" diameter furnace because much of a #200 or #300 bilge is smaller than its maximum diameter at the bulge area.

    I would run two standard pressure nozzzle burners, each running at 3 gal/hr.

    Edit:
    I would use a swing crane (not sure the correct term), ie: a pole with an arm on it that swings horizontally, and put the molds in a circle, and pour them in a radial fashion.

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    Last edited: Feb 2, 2020
  5. PatJ

    PatJ Silver

    An A20 does not hold 551 lbs.

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  6. OMM

    OMM Silver

    You're a quick gunslinger. Go back and check the rest of my edit and then decide on the outcome.
     
  7. PatJ

    PatJ Silver

    LOL, just call me "Quick-Draw-McGraw".

    Yes, that is what I thought you intended.

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  8. OMM

    OMM Silver

    at the suggested 90% full would be 496 pounds subtract 1.2% for expansion = 490 pounds total. So my guess is somewhere in between the other two.
     
  9. PatJ

    PatJ Silver

    And I think the point is, you can melt a whole lot of iron in a 24" diameter, 28" tall, dual-oil burner furnace.
    I don't need that kind of metal, but as I said above, I think you could use a #300 with a 28" tall furnace, and melt close to 900 lbs/melt.

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  10. DavidF

    DavidF Administrator Staff Member Banner Member

    Why anyone would rate a crucible in lbs of brass which is an alloy that can vary greatly is beyond me....
    And according to google, the weight of iron per ci is 255 lbs... roflmao!!! No wonder the world is so F ed up..
    SmartSelect_20200203-010108_Google.jpg
     
  11. DavidF

    DavidF Administrator Staff Member Banner Member

    Ok so
    31.88 litres one liter is 61.24 cubic inches...
    Iron .28 lbs per ci....
    So.... 546 lbs??
     
  12. OMM

    OMM Silver

    It really depends on where your efficiency lies.

    If I had to pay for fuel with a every day pour (under 50 pounds).... I would probably go with natural gas.
    But..., if it was once a week or once biweekly, I would look into a dual fuel or triple fuel burner.
    More than 50 pounds per day I would be seriously looking into coke as a fuel.

    For fun, let's just say if you're using a room temperature liquid fuel (ie. diesel, WO, WVO)(and your furnace is fairly efficient for energy loss). A 1:1 fuel L to iron L/hour melt could be achievable for cast-iron.

    1 L of fuel creating 1 L of molten cast-iron in one hour. Or 1 kg of solid fuel creating 1 L of molten cast-iron in one hour. and... Cost for each= efficiency.

    Efficiency doesn't stop with just one firing. Break down cost, maintenance cost, Labour cost, fuel cost, material replacement cost, all have a high impact over a lifecycle of efficiency.

    Everything wears out in time. Finding the least cost demographic, will never be achieved across the board.

    But,… I do think 1L:1L= a good goal.
     
  13. OMM

    OMM Silver

    In what year did the USA Congress government officially announce they were going metric? 1 L of water = weighs 1 kg (or 2.2 pounds). Most of the British colonies have gone metric (World). We are still waiting for the USA to fully adapt metric. Metric has now been dominated 97% of the world.

    Water freezes at 0°C and boils at 100°C.
    A big bottle of soda is 2 L., not 67.628 fluid ounces.
    I personally hate mixed measurements. How tall are you?(5' 11" 11/16")(ME)????=1.819M=1.82M, Close enough.
    Your weight is not 200 pounds, it is 90.7 kg.

    A safe road trip travelling speed is 100 km/h (with 12 lanes going in one direction) or 62.137 mph.
     
    Last edited: Feb 2, 2020
  14. PatJ

    PatJ Silver

    I was waiting on that too, but now I realize that it will never happen.

    As an engineer, I can work in any units, but the problem with metric (in one person's opinion who is in the construction industry) is that it does not have simple rules of thumb (so so speak), such as a foot = 12 inches, a yard = 36 inches (does have the meter, which is similar to the yard), and stuff like 4x8 sheets of plywood.

    Everything in the US is referred to in feet of wire, feet of conduit, feet of ductbank run, a 100 foot x 200 foot building, a 3 foot by 6 foot concrete pier.

    Nobody I know of in the construction industry refers to a 15,000,000 mm x 12,000,000 mm building, or nonsense like that.
    Its far too awkward, and I fully believe that most construction in the US would grind to a halt overnight if the metric system was forced here.

    Everything is broken down here in building increments that work around feet.
    A concrete block is 8"x16" on its face, and a 10 foot tall wall works out to an even number of blocks.
    Bricks are the same way.

    All materials, fittings, fasteners, and tools in construction generally use the same US standard.
    I do keep a set of metric tools to work on my car, but nobody I am aware of in the construction industry keeps two sets of tools to do "imperial" and "metric" construction projects.

    There are many things done in Europe that I and all the engineers I know consider substandard to the US method, such as IEC-rated electrical gear instead of NEMA-rated gear.

    On paper, metric sounds great.
    Building a building with US building materials makes metric a nightmare, and nobody does it here that I am aware of (perhaps the government forcing some poor bstard to use it, in their infinite efficiency).

    I use decimal inches, or sometimes feet and inches (generally if the distances get over about 10 feet, I start using feet and inches), but I never use fractions for anything.
    I see no need for fractions of an inch used for anything, but drill sizes seem to be stuck with that for standard sizes.

    I have never seen a metric measuring tape in the hardware store.
    Nobody would have a clue here how to use one if they did get their hands on it.

    The best I have seen is building material dual-labeled, but it is a 4x8 sheet of plywood with a metric label, and not some metric-sized sheet of plywood.
    Building studs are the same way, 2x4, 2x6, 2x8, 2x12, etc.

    Structural steel is a W12 x 50 or something like that, with the 12 being inches.
    I don't see metric building steel, but it may be out there.
    I have never seen metric on a structural drawing, and I have seen a lot of structural drawings here.

    We use to build large steel facilities for a German company, and all the drawings they sent us were in German language, and in metric, but the buildings we built for them were not built in metric. We all had to buy English/German dictionaries. It was either learn German or not be able to do the project.

    If I were an machinery manufacturer, and did not have to build buildings, I could live with metric without too much problem.

    Feet and inches are here to stay in the US.
    The US feet and inches is a good system, easy to follow, and works well in the building industry.
    If its not broken, don't fix it.

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    Last edited: Feb 3, 2020
  15. PatJ

    PatJ Silver

    I am not sure how long a 600-800 lb iron melt would take.
    Seems like I recall ironsides talking about someone doing that, and the time was in hours, such as 2 or 3 hours as I recall.

    Seems like Jason was taking perhaps 1.5 hrs for his #70.

    I am going to go do some math on this....

    Here is a bit of oil usage data vs what I think must be kg of iron.

    Morgan-01.jpg
     
  16. PatJ

    PatJ Silver

    A Morgan size 4 furnace appears to be about 30" tall inside, and varies from about a 20" bore at the top to perhaps a 22" bore down lower.
    Seems like the necked down design would really hamper getting the lifting tongs in place, and I have not seen this on the MIFCO furnnaces.

    I think ironsides said the numbers given for a Morgan size 4 furnace are optimistic, but not really reality, but they do give a rough starting point as you go into the larger melt sizes.

    An example from the Morgan chart above for a size 4 furnace:
    90 minutes
    300 lbs of iron
    11 gal of oil (or diesel)

    The fuel usage is not linear, ie: for a size 1 furnace, the fuel usage is 14 liters per 20 kg, or 0.7 liters per kg.
    For a size 2 furnace, the fuel usage is 21 liters per 50 kg, or 0.42 liters per kg.
    For a size 3 furnace, the fuel usage is 25 liters per 80 kg, or 0.3125 liters per kg.
    And for a size 4 furnace, the fuel usage is 42 liters per 135 kg, or 0.311 liters per kg.

    The trend seems to be that a larger furnace runs more efficiently than a small one?

    So guessing at the fuel usage if you wanted to melt 800 lbs of iron, if the trend held above, then you could use perhaps 30 gallons of fuel or more.
    So maybe $100 - $150 in fuel.

    For high-value parts, the fuel cost could be negligible.

    Sand molds would get heavy, and I could see molding large items on the floor as they did in the old days.

    At some point, I think for continuous runs, induction would be cheaper, but folks like me will never have a 480 volt, 3-phase service, and once you set that demand once, they will charge you the same demand charge every month whether you use the service or not.

    Oil is a poor-man's induction furnace, and a backyard person could get away with some 800 lbs melts on the cheap, assuming it made sense to have melts that large (I guess at a large art pour where they are pouring by the ton, like they do here at the Metal Museum).

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  17. Rotarysmp

    Rotarysmp Silver

    Back to the original video which was linked, I am suprise how short and fat it is. I thought there was a pretty narrow range of height to diameter for cupola to work well, and that one looks way shorter than most that you see.
     
  18. PatJ

    PatJ Silver

    I am still not seeing the logic in that cupola design.
    I watched it again, and he says "the slag comes out the back", but then at 2:25, you have all sorts of slag buildup on the pouring spout, and it is breaking off and going right into the ladle.
    The ladle appears to have all sorts of slag in it.
    Seems like the castings would be full of slag inclusions, although he does have someone skimming during the pour.

    The whole idea of having the clay plug is to break it and then get a clean stream of iron running down a clean spout.

    Even if he is pouring out of the bottom of the cupola with a botom-feeding spout, he is still doing a poor job of keeping the spout cleaned off, and I see no quality control in the way he is doing it.
    Not trying to be critical, but I see too many issues with tilting the cupola, and I don't see any benefits.
    How hard is it to break out a clay plug?

    Edit:
    In the video comments, it is mentioned that the tilting mechanism allows a sort of on-demand tilt-and fill as needed, I guess without the typical gusher spewing out when the clay plug is broken, so that there is more control of how much is tapped. More like a beer tap sort of thing. Tap a bit as needed (as he mentions in the comments).

    I can see the merits of controlling the flow, but I would still block off the spout with clay to keep it from building up slag, as it does in the video.
    If it works well for him, then that is all that really matters.
    I still see a lot of slag breaking off that pour spout; that is clearly visible at 2:25.

    Blocks are for sale here:
    https://www.etsy.com/shop/badbendforge
    $445.00 per block, 60 lbs, that works out to $7.42 per lb of iron.

    I would think you would want this item to be made from ductile iron to keep it from cracking?

    Edit:
    1:51 shows the cupola after the dump out the bottom.
    It appears to be sort of a short, squat cupola, but I think that may be an optical illusion because it is not elevated up on legs as you see with most cupolas and cupolets.

    And that may be another good feature is that the entire cupola is much lower to the ground, and you do have to lift every bit of that iron and coke up and into the top of a cupola.

    It is a two-piece shell design, and the top part necks down, and is removable.
    It does not use a lid, which would make it a cupolet if it had a lid.

    I guess the interior diameter can be any size, as long as you know how to get the coke and iron to bridge properly.


    By comparison, the cupola at the Metal Museum is a one-piece shell, and so that makes for sort of a long reach to patch the refractory.
    Metal Museum cupolet interior shown below.
    It has a 16" internal diameter, and is 37" tall.

    r20190515_164557.jpg


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    Last edited: Feb 3, 2020
  19. PatJ

    PatJ Silver

    Here is a comparison side-by-side of the cupolet arrangement I am use to seeing around these parts (on the left), and the tilting cupola design on the right.
    The cupola on the right does seem to be rather wide and squat, with quite a low air header on it.
    I don't know enough about cupola's to really understand the differences, but apparently there are many ways to make sliced bread.

    If the centerline of the tilting furnace hinge point was not low enough, it would be rather difficult to tilt the furnace when it is full of metal.

    Tilting-Cupola-Comparison-01.jpg
     
  20. rocco

    rocco Silver

    I would think it would be quite difficult to get the tilting axis just right, position the pivot for easy pouring then to would be rather top heavy (hence tippy) when you first load it. This one looks it dealt with that issue by using a reduction gear on one of the pivots to aid pouring.
     

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