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Thread: Why is this guy hammering these Toishi?

  1. #1

    Why is this guy hammering these Toishi?



    What gives?

  2. #2
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    sachem allison's Avatar
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    listening for cracks and flaws. The sound will change if there is a hidden crack.
    I haven't lived the life I wanted, just the lives I needed too at the time.

  3. #3
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    I will be disappointed if Maxim's next video does not have some stone hammering.

    This is not something I will be trying at home.

  4. #4
    Senior Member markenki's Avatar
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    Is that what those hammers are for? Interesting.

  5. #5
    Senior Member Lucretia's Avatar
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    It's a pretty darn good way of finding defects.

    Back in the dark ages when I worked on the Atlas Centaur rocket program, the rocket had a nose cone (fairing) made out of fiberglass honeycomb sandwiched between solid sheets of fiberglass. The air in the honeycomb is at sea level/atmospheric pressure, and when the vehicle was launched, as it moved into space and external pressure approached a vacuum, the air in the honeycomb would push outward against the fiberglass skin. If there were large enough areas where the skin wasn't attached well to the honeycomb, the fairing would tear itself apart.

    There was a lady with a well-trained ear that they used to fly from Houston to Cape Canaveral to do a "coin-tap" test--basically rap the entire fairing with a hammer and listen for voids where the skin wasn't attached to the core. Not high tech, but effective.
    Now is not the time to bother me. And it's always now. Wiley Miller

  6. #6
    Harder stones have different density and different sound when hammering on them, it is a way to test how hard/fine stone is.

  7. #7
    Senior Member brainsausage's Avatar
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    Quote Originally Posted by Lucretia View Post
    It's a pretty darn good way of finding defects.

    Back in the dark ages when I worked on the Atlas Centaur rocket program, the rocket had a nose cone (fairing) made out of fiberglass honeycomb sandwiched between solid sheets of fiberglass. The air in the honeycomb is at sea level/atmospheric pressure, and when the vehicle was launched, as it moved into space and external pressure approached a vacuum, the air in the honeycomb would push outward against the fiberglass skin. If there were large enough areas where the skin wasn't attached well to the honeycomb, the fairing would tear itself apart.

    There was a lady with a well-trained ear that they used to fly from Houston to Cape Canaveral to do a "coin-tap" test--basically rap the entire fairing with a hammer and listen for voids where the skin wasn't attached to the core. Not high tech, but effective.
    I love stories like this. Weird background stuff that you never realize is making an impact. No pun intended. Fun video too.

  8. #8
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    Quote Originally Posted by Lucretia View Post
    It's a pretty darn good way of finding defects.

    Back in the dark ages when I worked on the Atlas Centaur rocket program, the rocket had a nose cone (fairing) made out of fiberglass honeycomb sandwiched between solid sheets of fiberglass. The air in the honeycomb is at sea level/atmospheric pressure, and when the vehicle was launched, as it moved into space and external pressure approached a vacuum, the air in the honeycomb would push outward against the fiberglass skin. If there were large enough areas where the skin wasn't attached well to the honeycomb, the fairing would tear itself apart.

    There was a lady with a well-trained ear that they used to fly from Houston to Cape Canaveral to do a "coin-tap" test--basically rap the entire fairing with a hammer and listen for voids where the skin wasn't attached to the core. Not high tech, but effective.
    A great story. I don't know what i could add. Maybe i'll start tapping on things/people listening for voids . . .

  9. #9
    I figured it was to find faults in the stone, but who cares? Thay doesn't denote performance, does it?

  10. #10
    It is not to find faults in the stone, its for finding out hardness of the stone

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