Explosive Metal Forming

[Tuatara]

Here's a real world explosives application for those who are bored with making craters, or demolishing trees.

Explosive metal forming is a method of super-plastic forming of metal sheet using explosives to provide the force / energy.

This link outlines the process nicely.
Overview of explosive metal forming (http://www.metalwebnews.com/howto/explosive-forming/explosive-forming.html)

I had a friend who was considering making aluminium canoe hulls this way, as there would be no below waterline welds or joins.

Anyone played with this stuff before?

[knowledgehungry]

I have never Tried this but SWIM was once playing with APAN in a watch, and when he detonated it the back piece of the watch bent in a U-shape over the wristband. SWIM has been thinking about making some SC cones using explosives. Perhaps over the summer.

[Mr Cool]

I've tried making an EFP platter, it was only about 5cm accross so I used copper sheet about 0.2mm thick. The charge was tiny, quarter, maybe half a gram at most, seperated from the metal by a few cm of flour/water paste. The mould was plaster, made using a light bulb.
Anyway, upon detonation the mould broke and the metal was totally ripped apart.
But if you made a cone by folding a sheet of metal, then you might be able to seal the edges together, to form a seamless cone, by overlapping them by a mm and explosively welding it with a few layers of tissue paper soaked in NG over the overlap...

[nbk2000]

Explosively formed shapes are done using machined steel forms. The form is either pumped to vacuum, or has many holes drilled in it to allow the air to escape when the metal is driven into it.

The metal forms a barrier between the form and the water in the chamber above it. The explosive charge is placed in the water and the hydrostatic pressure induced by the explosion deforms the metal into the form.

Also, there's all kinds of limitations on what kind of shapes you can produce, due to elasticity, ductilility, malleablility, etc. Too thick, it won't deform. Too thin, it'll tear like tissue paper. You got to be like goldielocks and get it just right. ;)

[kingspaz]

shaped charge cones anyone :confused: ???