Re: hydroforming : was water spark gaps

["Tesla list" <tesla-at-xxxxxxxxxx>]

Original poster: "bob golding" <yubba-at-clara-dot-net> 

Hi all,
	while looking around for info on hydroforming I noticed that there is a
related method that uses high pressure water/oil mixtures. This might be
a safer method, at least for me ,I don't think the neighbours, or the
police for that matter, would let me get away with explosives. I was
thinking something like an hydraulic pump of an old JCB (back hoe) might
do. It also has the advantage of being a bit more controllable
/repeatable. Jim, any titles of books, I looked on Amazon, and came up
with 169 titles.

cheers
 bob golding

Tesla list wrote:
> 
> Original poster: "Jim Lux" <jimlux-at-jpl.nasa.gov>
> 
> spark hydroforming is very practical.  As Terry points out, explosives are
> also used.
> 
> The advantage of explosives is higher energy density... getting 50 kJ out
> of some high explosive is easy (typical: 50 kJ/gram).. getting 50 kJ out of
> an energy storage cap is a bit bulkier.  However, in a production
> environment, the electrical approach is much easier: all you buy is
> electricity (and replacement caps periodically), and you don't have the
> byzantine laws and regulations surrounding the purchase, storage, and use
> of explosives.  By the way, I haven't tried it, but I suspect that low
> explosives (like black powder) wouldn't work too well. All the explosive
> hydroforming I've done has been with real stuff (PETN in the form of
> detonating cord) which has a very high detonation velocity.
> 
> Before you embark on electrical hydroforming, it's a good idea to get an
> feel for how much energy you're going to need to do your forming.  10 kJ is
> like dropping a 1 ton weight 1 meter... Your spark gap is going to
> essentially radiate the energy in a sphere, so much of the shock wave won't
> intercept your work piece.
> 
> However, it is interesting and fun to try...  There are books on this
> available, as well.