How do you turn molten metal into perfect spheres? Just pour it off the roof
Posted 09.04.2008 at 1:39 pm
6 Comments
Real Deal
The Sparks Shot Tower in Philadelphia was built in 1808.
John B. Carnett
About 230 years ago, molten lead that rained from the sky—historically something to avoid at all costs—became a clever new way to manufacture an important commodity: shotgun ammo.
Precisely round pellets fly straighter, but casting each in its own 1/8-inch mold isn’t exactly mass production. In space, making them would be easy. In zero gravity, surface tension pulls any liquid into a sphere, the shape with the least surface area for a given volume. This is as true for molten metal as it is for drops of water floating inside the space shuttle. On Earth, the closest thing to zero gravity is freefall—falling objects experience weightlessness right up until they hit the ground.
Steady Drops:
A vibrating motor shakes the stream of molten lead falling out of this inverted oil can, the modern way to make precisely sized metal beads. Mike Walker
Replicating this is easy, except for the six-story height. I used my hydraulic lift to get about 40 feet up, but that wasn’t enough; the lead was still molten when it hit the water, and I didn’t get good pellets. (I decided not to climb to the top of my windmill with a pan of molten lead. Sorry, you’ll have to live without photos of perfect modern drop shot.)
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How is it not obvious to you that what readers will want most after reading your article is photos of the final product?
How spherical are they? How uniform are they?
What a letdown!
Hah, nevermind the final product.. What worries me is people actually trying it out. Get on a tall building and try it. But then you have another idea: what do you do with the already made "ammo"... A use needs to be found...
Trouble ahead :P
- DiGGY
Incidentally, this is the technique used to make Dippin' Dots, the expensive ice cream that comes in tiny, frozen pea-sized spheres. When making it they allow the ice cream to freefall as tiny liquid droplets through a super-cooled (probably -30^F) air chamber. They freeze on the way down and reach the bottom almost perfectly round.
What's obvious is that andrewl did not read the article. He could get high enough for the shot to cool properly, thus when it hit the water it deformed.
As for a use, sling shot ammo.
what is suggested is what is possible only in space.when it comes to earth,the results are unpredictable as dealt with various metals,at varying lab conditions.well it's not a mass production at all as described.none is a fool to invest huge on "virtual space creation"to form perfect metal spheres.also i feel that's impossible also.so far,latest casting techniques have produced the most perfect spheres in mass production.i find the technique a triffle needless in terms of money and feasibility.
wow, that is briliant
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