Core Print Design for Bell

Discussion in 'Pattern making' started by Tops, Dec 17, 2022.

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  1. Tops

    Tops Silver Banner Member

    Hello Everyone,
    Thinking about casting a bell as a gift for a bell collector in the family.
    The core print would be about 2.6" [67mm] tall and round in a tapered shape, part wall is about 3/32"[2.4mm] and will be in aluminum.
    Wondering if the base for the print (dark gray) and pattern (tan) at .75" [19mm] tall is enough?
    Thinking about 3D printed patterns and core molds and 2 to 5 % 2:1 epoxy in fine sand for the core material.
    Thanks!
    tops_corepint1.png
     
    Last edited: Dec 17, 2022
  2. rocco

    rocco Silver

    Depends on how you cast it. I think it's probably most appropriate to cast the bell vertically otherwise, you're likely to run into problems keeping the core properly centered in the mold. If you cast horizontally, the base of the core would need to be much longer.
     
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  3. Tops

    Tops Silver Banner Member

    Thanks Rocco, I had not thought of that and it makes sense, use gravity and the molten metal along with the core print to keep things centered. Otherwise you are fighting gravity with the weight of both core and metal as it is cantilevered from the print.
     
  4. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    If you're going to go to the effrot, why not one of the more typical bell bronzes..........80/20 Copper/Tin range. It will sound much better!

    Best,
    Kelly
     
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  5. Tops

    Tops Silver Banner Member

    Kelly, It would be nice to try some other metals besides aluminum...and have a bell that really rings. This is my first core so my thoughts wandered back to aluminum.

    Do people have preferred sources for small amounts of casting metals in various alloys is the US? Belmont?
     
  6. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Nothing wrong with proving out your mold with Al, but just doesn't seem to ring true for the finished item :)......Both Copper and Tin are fairly spendy right now, but since the part is relatively small, that may be practical if you dont have access to scrap. The other thought may be someting that casts well, like SiBr, especially if it's also a first time casting bronze. Just the same, I'd be tempted to scrounge up a scrap valve body.

    The other thing about bells, I know it's tempting to gate into the top, and many do successfully, but I think a circular runner at the base with say maybe four gates, and vent/riser at the top is a far better arrangement. Pouring in the top just causes the metal to tumble to the bottom in a very disorganized fashion, while bottom feed holds the promise of a tranquil bottom up fill with a top down directional solidification. If that's a handle on top, you may also need a generous riser up there. Makes for a little larger mold but potentially better result. There are several members that have/do cast bells. They may chime in.

    That's my 2 cents.........you can tell I'm old.....pennies arent copper these days. ;)

    Best,
    Kelly
     
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  7. rocco

    rocco Silver

    I've probably got about $25 worth of old Canadian pennies that I'm saving just in case I want to cast some bronze. The pre-2000 Canadian pennies are a high copper, low tin bronze and the 2000+ pennies are copper plated steel so they're easy to sort out with a magnet. Sadly, pennies have been out of circulation here for about ten years now so they're are a finite resource. BTW, American pennies have been made of 97.5% zinc since 1982, prior to that they were 95% copper/ 5% tin.
     
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  8. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    And silver dollars were Silver! No-more.

    Best,
    Kelly
     
  9. rocco

    rocco Silver

    The Royal Canadian Mint still issues a number of silver and gold coins each year including silver dollars, however these are not regular circulation coins, they are either commemorative coins targeted at collectors or bullion coins targeted at investors. We do also have circulation one and two dollars coins but these are not silver.
     

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