Re: Exploding wire (fwd)

["High Voltage list" <hvlist@xxxxxxxxxx>]

Original poster: Steven Roys <sroys@xxxxxxxxxx>



---------- Forwarded message ----------
Date: Tue, 28 Nov 2006 09:19:32 +0000
From: Mike Harrison <mike@xxxxxxxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: Re: Exploding wire (fwd)

On Mon, 27 Nov 2006 21:33:56 -0700 (MST), you wrote:

>Original poster: Steven Roys <sroys@xxxxxxxxxx>
>
>
>
>---------- Forwarded message ----------
>Date: Mon, 27 Nov 2006 10:24:38 -0800
>From: Peter Lawrence <Peter.Lawrence@xxxxxxx>
>To: High Voltage list <hvlist@xxxxxxxxxx>
>Subject: Re: Exploding wire (fwd)
>
>Jim,
>    wow, and I thought the difference would be whether the vaporized
>metal would burn or not, aluminum is very combustable, copper is not,
>iron is somewhere in between, and I was having a hard time imagining
>how the vaporized metal could mix with air efficiently enough to get
>some secondary energy out of the system...
>
>-Pete Lawrence.
>


There is certainly a huge difference  between exploding copper and steel (guitar strings are good) -
with the latter you get a really spectacular shower of sparks as the metal burns. 

There is some 1000fps high-speed camera footage of this on my site : 
http://www.electricstuff.co.uk/fastdestruct.html (bottom of page)

Also some frame sequences here : 
http://www.electricstuff.co.uk/explode.html


>
>High Voltage list wrote On 11/23/06 06:36 AM,:
>> Original poster: Steven Roys <sroys@xxxxxxxxxx>
>> 
>> 
>> 
>> ---------- Forwarded message ----------
>> Date: Wed, 22 Nov 2006 21:48:30 -0800
>> From: Jim Lux <jimlux@xxxxxxxxxxxxx>
>> To: High Voltage list <hvlist@xxxxxxxxxx>, hvlist <hvlist@xxxxxxxxxx>
>> Subject: Re: Exploding wire (fwd)
>> 
>> At 08:41 PM 11/22/2006, High Voltage list wrote:
>> 
>>>Original poster: Steven Roys <sroys@xxxxxxxxxx>
>>>
>>>
>>>
>>>---------- Forwarded message ----------
>>>Date: Wed, 22 Nov 2006 11:17:35 -0800
>>>From: Peter Lawrence <Peter.Lawrence@xxxxxxx>
>>>To: High Voltage list <hvlist@xxxxxxxxxx>
>>>Subject: Re: Exploding wire (fwd)
>>>
>>>
>>>
>>>
>>>
>>>>>Hello All,
>>>>>
>>>>>
>>>>>
>>>>>I just bought 1400ft of .008, 32AWG piano wire. My Capacitor charge will be
>>>>>14.3uf @ 40KV, I could do up to 50KV but the history of the Geek 
>>>
>>>Mighty Caps
>>>
>>>>>is unknown. How many feet can I blow of this wire? Surely this 
>>>
>>>would be more
>>>
>>>>>spectacular then a copper wire. Am I in the right ballpark for gauge? I
>>>>>would like to reach 8 feet ~ 2.5 Meters. The caps are rated at near 9KJ at
>>>>>full charge.
>>>>
>>>hmmm, vaporized metal is vaporized metal, not sure why anyone would expect
>>>iron to be much different from anything else...
>> 
>> 
>> 
>> The kind of metal has a fairly significant effect.  It changes the 
>> resistance, so the trade between resistance and inductance is 
>> different. Ideally, you want the resistance to be such that the 
>> circuit is close to critically damped, so that all the energy is 
>> absorbed by the wire in that first quarter cycle, as opposed to over 
>> multiple cycles as the circuit rings down.  For a given 
>> configuration, there's not much you can do about inductance.
>> 
>> There's also a tradeoff in the amount of energy it takes to fuse and 
>> then vaporize the wire, which is different for different metals, not 
>> only because the melting and boiling points are different, but 
>> because the density of the materials are different.  The thermal 
>> capacities are similar for most metals.
>> 
>> but wait, there's more: the temperature coefficient of the resistance 
>> is also different for different metals.  As the wire gets hotter, its 
>> resistance increass, changing the circuit properties.
>> 
>> 
>> This is all very difficult to predict easily, hence the "try it and 
>> see if it works" advice.
>> 
>> Jim
>> 
>> 
>> 
>>>but then, I can't actually predict the outcome either, so let us know how
>>>it turns out !!!
>>>
>>>-Pete Lawrence.
>> 
>> 
>> 
>> 
>> 
>
>