My grandson wants to try casting

Discussion in 'General foundry chat' started by garyhlucas, Dec 16, 2018.

  1. PatJ

    PatJ Silver

    Ah ha, there is another lid-within-a-lid design.

    Nice equipment.
     
  2. Petee716

    Petee716 Gold Banner Member

    I can see how that ring could get in the way. Bolt cutters would make short work of it. You could always replace it if you decided to use a hoist later (never say never!lol). Those tools are designed for a specific size crucible, or at least a very narrow range of sizes, so they're more fitted to the crucible than the furnace. What lends to their robustness is the weight of the metal you're lifting or whether you're running a one-man show. There are many posts here and on AA of some pretty effective "helper" devices for heavy one-man pours. Melterskelter and Rasper are two that come to mind.
    I attached a picture of a lifting/pouring tool I mimicked from Myfordboy. He has a great video posted on YouTube of his build. His are nicer looking than mine, but mine work well. They were built for a #10 clay graphite from Legend but I also use them for a #7 by bolting in a set of reducing shims to the interior of the ring. I've used them to pour bronze with a #10 but between their light construction and play in the linkage I wouldn't use the design for anything heavier. I recently added a #16 to my arsenal and built a more conventional set of pouring tools for it.

    image.jpeg

    Scrap automotive castings are a great resource. Transmission bell housings are good alloy and break easily with a sledge. Rendering scrap to a useful form for crucible melting is another well travelled rabbit hole on the forums as I'm sure you will find, but simpler is better! 6061 will melt, and it will pour, but casting alloys will put you in the best position to get successful castings.

    Pete
     
  3. 6061, as well as aluminum cans will cast ok. It's usually free in sources like old ladders and window frames so it's cheap to practice with. For general casting you'll do well with it. A lot of guys don't like unknown scrap aluminum but it works well to start with.

    Engine parts (watch for magnesium in small engines) like intake manifolds are a good source of cast aluminum, as is cast wheels.
     
  4. DavidF

    DavidF Administrator Staff Member Banner Member

    Here is the biggest problem with using scrap.
    What alloy is it? How much shrink allowance is needed in the pattern?
    Might seem trivial if what you are casting is just for decoration, but if you need a part that will be subject to some stress or stay within tolerance when cast, using a known (certified) alloy is best.
     
  5. I understand the desire to use a known alloy. But scrap is certainly good for practice. It's not like it won't give you good castings. When you start casting for hire it is important to use a known alloy unless, as was said, for decorative items.
     
  6. garyhlucas

    garyhlucas Silver

    In looking into this futher the biggest different in composition between 6061 and A356 casting allow appears to be that A356 has a lot more silicon in it, 7% or so. So does that suggest that adding silicon to a melt of 6061 would make a better casting alloy?

    I have quite s bit of 6061 scrap as I machine parts from this all the time.
     
  7. garyhlucas

    garyhlucas Silver

    So I modified the tongs a bit. I need to get a self-locking clevis pin for the end of the turnbuckle instead of the bolt and nut.

    Out of the furnace, pour, and back in the furnace without setting the crucible down. Tongs are locked closed so no chance of dropping it or tipping it over.
     

    Attached Files:

  8. HT1

    HT1 Gold Banner Member

    in simple terms
    The composition of 6061 does not cast well without using special techniques , like centrifugal casting because all that additional Silicon increases the Flowability of the Molten aluminum. it makes it more liquid.

    there is a very simple reason that there are entirely different specifications for cast and forged alloys. they are made for different purposes. you will avoid problems by using casting alloys.

    V/r HT1
     
  9. garyhlucas

    garyhlucas Silver

    I work with metals all the time so I understand that the alloys have very different properties for good reason. A long time ago a guy asked me to Tig weld an alternator bracket back onto a Volkswagen Beetle engine block. I tried welding it using the typical 4043 filler. The weld was beautiful. Then it cooled and there was a pop and the weld literally fell out of the joint onto the floor, clean as could be! So I had him get me a piece of another broken bracket which I sliced into strips on the bandsaw. Using that as filler worked perfectly and he was off and running.
     

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