Re: Exploding wire (fwd)

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

Original poster: Steven Roys <sroys@xxxxxxxxxx>



---------- Forwarded message ----------
Date: Mon, 27 Nov 2006 21:14:53 -0800
From: Jim Lux <jimlux@xxxxxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>, hvlist <hvlist@xxxxxxxxxx>
Subject: Re: Exploding wire (fwd)

At 08:33 PM 11/27/2006, High Voltage list 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.
>
If you're really doing an "exploding" wire, then burning doesn't 
enter into it.  It happens in microseconds.

In fact, it's when the current rises slower you get to see the 
burning (which is also a very cool effect, by the way)... at some 
intermediate stages, the wire melts, but doesn't vaporize.  Surface 
tension makes it break into segments, which then spark over, and 
start it burning, and you get something that greatly resembles fireworks.

Steel/iron burns yellow, aluminum a nice bright white, copper a greenish color.

When you explode the wire, it also gets a color cast for copper, and, 
you'll get a reddish copper oxide smoke and white smoke for Aluminum 
oxide, but overall, it's just a blinding flash.

However, it's the shock wave from the exploding wire that's the most 
qualitatively noticable thing.