anachronism

Discussion in 'New member introductions' started by anachronism, Sep 8, 2019.

  1. :) I signed up on AA so I could blow up the pics of FishbonzWva build since it is really close to what I had envisioned. I even already have two of the same size drums set aside in my garage for the project. The ceramic wool coated with refractory certainly seems simpler than trying to do a major one-piece pour in a cut down 15 gal drum. I wasn't looking forward to that part, and now it seems unnecessary. My choice of propane to start out with is based on simplicitys sake, it's just easier to get started with, and I can always upgrade to an oil burner later without modifying the furnace body itself. The actual burner is likely to be a modified weed burner although there are commercial burners available that wouldn't require modification at all. I was planning on shortening the weed burner a bit to make it a little less awkward to maneuver. I haven't even built the first furnace yet and I'm already thinking about building a smaller one out of a five gallon racing fuel can I have set aside for.... something, I guess. It looked too useful to toss into the scrap at work. My plans are gelling really quickly now, and I that you all for your suggestions and recommendations!
     
  2. Jason

    Jason Gold

    The interim propane stop isn't really necessary. An oil burner is dead nuts simple. OMM has a thread going right now on his take on the simple Kwiky. You can start it and run on cheap diesel. You will need a small blower and an air compressor to venturi the fuel into the furnace. You can even run propane through a Kwiky too!

     
  3. OMM

    OMM Silver

    I do! And, I enjoyed building the quicky and learned a little bit well I was building it.

    But, it was a little big for my liking. And it had trouble pulling enough used motor oil or vegetable oil through the 3/32 hole without thinning. After finding a reliable source for waste vegetable oil I came up with a burner of my own design that uses only 5 pieces and A copper wire. My burner now is almost the size of a sharpie. I will be installing two of them in my furnace. My furnace will have about 11.8” inside diameter and a inside height 15.5”. I might be able to squeeze in A25. But my goal is a 8, 16, 20.

    This is just a prototype. The big knurled thumb wheels won’t be on the finished product burners.
    0871E447-E193-467B-BFD1-9F258C8DFC1D.jpeg
     
    Last edited: Sep 11, 2019
  4. FishbonzWV

    FishbonzWV Silver Banner Member

  5. Such practical solutions, all based on actual experience, not 3rd hand Youtube videos. What a great group!
     
  6. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    If you do decide to use propane, the naturally aspirated Reil style burners are simple, inexpensive, and effective.

    burner.gif

    Or, if you a have blower, even more heat can be available with forced air. You'll need to buy yourself a higher pressure propane regulator either way. The regulators for grills don't cut it.

    Best,
    Kelly
     
  7. Wow, lots of differences in crucibles. I see three basic groups, budget, premium, and super premium. My first impulse was to go up the middle with premium, but even that's a bit pricey. Are the budget crucibles worth considering? I don't want to shortchange myself with a false economy. I'm sorting out the various sizes so I can calculate my plinth heights. I believe I'm seeing where some here are using interchangeable plinths, but that's going to require some careful consideration of tuyere placement. For the first furnace it appears my best choice would be to pick something in the #6 to #10 size range and work with it until I get a better feel for what I actually need sizewise. Am I barking up the wrong tree here?
     
  8. PatJ

    PatJ Silver

    I use Morgan "Salamander Super" clay graphite crucibles exclusively, and generally buy them on ebay.
    I highly recommend them for all types of metals, ferrous and non-ferrous.

    I have had problems with other manufacturer's crucibles, and have seen others with off-brand crucibles that fold up like a wet waffle when trying to melt iron.

    I went with two bags of refractory and made a 1" hot face, which weighs 120 lbs.
    The lid was another 40 lbs or so.
    I used Mizzou, and it seems to hold up well to iron temperatures.

    Here is a drawing you can use to get an idea of crucible sizes vs furnace size.
    My furnace is 13" inside diameter, and 14" interior height, with a 1" thick Mizzou hot face and 1" thick domed lid.
    I used IFB's around my hot face, and then two layers of 1" ceramic blanket, but just two layers of 1" ceramic blanket without the insulating fire bricks (IFB's) will work just as well.

    The lid also needs at least two layers of 1" ceramic blanket on top of it.

    It can use anything from a #10 (or smaller) crucible up to a #30 crucible.

    I would keep at least 2" clear between the furnace wall and the largest crucible that you plan to use.

    You can scale this whole furnace down to fit into a standard beer keg or some similar shape if you plan on using the smaller sized crucibles.

    Good luck.

    Edit:
    The top of the plinth, which is the same as the bottom of the crucible for the largest crucible, should be at the centerline of the burner / tuyere, or slightly above, to prevent flame impingement on the side of the crucible.

    I have several plinths, with each a different height.
    All my plinths are Mizzou.

    Elevating a smaller crucible in a larger furnace will improve melt times and melt temperatures.
    I run my #10 crucible with the top being within about 2" of the lid.

    The more mass a furnace has, the slower the melts will be.
    For melting aluminum only, the mass does not really matter other than you are wasting material building a high-mass aluminum melting furnace.

    KEG-FURNACE-REV-10B.jpg

    KEG-FURNACE-REV-10A.jpg
     
    Last edited: Sep 29, 2019
  9. Jason

    Jason Gold

    Expensive? you should see what these run. Makes a 40buck #8 graphite look cheap.
    20190929_212505.jpg
    Look on fleabay for jet tools seller. I've had good luck with those morgans. Price is decent too. Do not borax. Just heat and use.

    Here is a link for them.
     
  10. PatJ

    PatJ Silver

    You should temper the crucibles per the manufacturer's recommendation before first using them, so that you set the glaze.
    The glaze on the exterior of the crucible protects it from the flame/heat.

    Also note that the amount of metal that a crucible will hold in brass is about 3 times the crucible number, ie: a #10 crucible will hold about 3o lbs of brass, or 1/3 of that amount (about 10 lbs) for aluminum.

    The crucible # equals the approximate pounds of aluminum that the crucible will hold.

    A Morgan "SALAMANDER SUPER" is a graphite crucible.


    It can be used with both ferrous metals such as gray iron, as well as non-ferrous alloys such as aluminum, brass, and bronze.


    Typical metal casting temperatures are 1562 F - 2912 F (850 C - 1600 C).


    Color is black.


    The PREHEATING / FIRST USE instructions for fuel-fired furnaces is as follows (per Morgan):


    A new crucible shold be preheated empty in order to minimize the termperature gradient across the crucible wall. If there is a risk of the crucible having absorbed some moisture, then the furnace should be initially heated slowly up to approximately 392 F (200 C) and held at this temperature until all moisture has been driven off.


    A new crucible should initially be heated slowly and evenly to 1112 F (600 C) on low power, avoiding local impingement of flame on the curcible. Subsequently the full heat input rate should be utilized to achieve a uniform bright red condition over the whole crucible at approximately 1650 F (900 C) at which point the crucible should be charged immediately, taking care not to packing metal tightly or bridging ingots across the crucible.



    SALAMANDER-SUPER-A-SHAPE--CAPACITIES.jpg

    .
     
    Last edited: Sep 29, 2019
  11. Jason

    Jason Gold

    I did mine in the kiln. Nice and slow. Couple hundred degrees per hour until red hot. I shut it off, left it closed up and super slow cool down over night.
    No problems.
     
  12. OMM

    OMM Silver

    Correct me if I am mistaken.... I thought the sizes were metric kilogram for copper.

    Copper waights about 0.32 pounds per cubic inch
    Metal waights about 0.283 pounds per cubic inch
    Aluminum waights about 0.12 pounds per cubic inch (these are just the rough numbers I’ve used for about 25 years.) And titanium is about 0.14 pounds per cubic inch

    1 pound equals .454 kg. or…
    1 kg equals 2.2 pounds.
     
  13. Jason

    Jason Gold

    Not that I'm aware of Matt. It should be say a #6 holds 6pounds of aluminum or roughly 18lbs of bronze. Ya multiply the # by 3. Look at Pats chart above on the #6 size. These numbers are close enough. Ya NEVER fill it all the way up. Ask Jeff about that one. :p:eek::oops:

    You say metal weighs....... But "What is a metal?" There once was a video floating around here about what is a metal from an old professor. It was the funniest thing
    on a really dry subject. Anyone remember that or know where it is?
     
  14. OMM

    OMM Silver

    Jason, bronze and brass are very dis-similar alloys.
    Bronze usually 82%(or more) copper with about 6 to 12% aluminum.
    Brass can hold as low as 60% copper with tin (30%ish)plus plus plus.
     
  15. Jason

    Jason Gold

    Oh I'm getting an edjumacation on brass right now. It is definitely a lot lighter than bronze. This is why I use 3times the weight for bronze.;) Must be working, I haven't overflowed a crucible yet and I melt some seriously fat ingots. Now if I could just remember to weigh my wax before shelling, I'd never pour one short.:oops: (I probably could use 4 or 5 actually)

    I found this on budget casting supply.

    "A" Shape: Our "A" shape crucibles are typically used by hobbiests and casual casters. This shape is easier to make than the bilge shape and therefore is lower cost. Also note that "A" shape sizes and capacities don't correspond to bilge shape sizes and capacities. "A" Shape crucibles are rated in Kg of brass. For example a #6A will hold about 6 Kg of brass (13 pounds), (or about 4 pounds of aluminum).

    Where is david with the spec gravity crap when ya need him.:p
     
  16. Peedee

    Peedee Silver

    There doesn't appear to one set in stone standard on crucible sizing so it would seem best to go with reputable manufacturer and use their info verbatum. I thought specific gravity was reserved for telling how good a pint of beer was or did I get destracted during that college lesson....

    PS: Love your new sign off on the bottom of posts Jason
     
    Jason likes this.
  17. Petee716

    Petee716 Gold Banner Member

    I've bought all of my crucibles from Legend Mining in Sparks Nevada.(look under "assaying"). All of mine are budget clay graphite and their capacity in kg copper is listed. That will get you in the ballpark for capacities. A #10 goes for about $35. I melt aluminum and bronze and have never had a problem. If I was casting weekly, could factor in ROI, or had deeper pockets I would probably buy better ones, but I've never had a problem with any of mine. My very first one is 6 yrs old and still in use.

    Pete
     
  18. PatJ

    PatJ Silver

    That is entirely possible, but the crucible size still works out to be approximately the weight in pounds of aluminum, although the amount is probably a "brim-full" quantity, with the actual usable amount being a bit less.

    The bilge shapes hold more metal for a given crucible size, but I find bilge shaped crucibles to be very difficult (but not impossible) to find.
    If I were running a commercial foundry, I would use all bilge shaped crucibles.

    .
     
  19. Jason

    Jason Gold

    And bilges are more expensive......
     
  20. Jammer

    Jammer Silver Banner Member

    I get my crucibles from Legend Ming also. They say Kilos of Copper, but I just make sure by filling the crucible with clean sand to the height I would be comfortable with handling. Then I pour it into a graduated beaker to see how many liters it is and convert to the weight of the metal.

    https://www.aqua-calc.com/calculate/volume-to-weight It has different metals and alloys, Copper, Brass, and Aluminium (note spelling). It doesn't have cast iron but type Iron and use the dropdown menu to find Iron. It might be for Aquariums but I've found it useful for all kinds of conversions.
     
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