I grew up in semi-rural Thornleigh on the outskirts of Sydney.  I went to the local Primary School and later the Boys' High School at Normanhurst; followed by the University of New South Wales.  

As kids we, like many of my friends, were encouraged to make things and try things out.  My brother Peter liked to build forts and tree houses; dig giant holes; and play with old compressors and other dangerous motorised devices like model aircraft engines and lawnmowers; until his car came along.

We both liked homemade rockets and explosives; but our early efforts, before the benefits of high school chemistry, generally resulted in the rockets exploding and the explosives fizzing.  You can read more about this in the article Cracker Night (click here).

Commercial firecrackers and gunpowder were generally more successful; although home-made nitrogen triiodide was always easy, and zinc dust and sulphur makes a pretty good rocket fuel.  We also had some fun with large gas filled balloons; and various means of firing marbles and other projectiles. 

Fortunately we had 'the sheep paddock', forming part of the property, for such experiments.  We only set fire to it once or twice when the grass was particularly long and dry. 

There was never any suggestion from parents that we should not be wiring up electric motors or installing flood lighting to repair cars under. We both had a healthy respect for high voltages and seldom got a 'shock'. 

We are both still alive and were never injured by one of our experiments (by other things occasionally). The parental policy was that we were warned and asked what safety precautions we were taking.  After all, we had seen first hand what happens when a length of copper wire falls across the 33KV local distribution grid and shorts it to the street lighting; talk about loud; and dark that night!  See the note below.

So we generally took appropriate precautions with things that might explode; as when Peter successfully warned his young apprentice Ian to run! just before his steel compressor bottle exploded, rattling the neighbourhood windows. The neighbours were used to the occasional window rattle; and once or twice a hole or two.

This experience with potentially exploding things came in handy many years later when I worked in research at British Steel.  I was employed as an economist, to analyse the value of the research, but quickly got drawn into active experimentation. 

My colleagues and I in the 'Forward Technology Unit' decided to test the practicality of an idea that one of them had for inexpensive explosive forming. 

Explosive forming involves setting up a high pressure shock wave in an incompressible fluid; we used water.  The shock wave needs to be of sufficient intensity to make a steel plate instantaneously plastic, like putty, and so form it to the shape of a mould.  But it needs to be not so powerful that it destroys the apparatus. 

Needless to say, the trials involved heavy muffled thumps and occasional flying bits. We set this up in the mini steelworks within the BISRA laboratory complex at Battersea in London.

When the safety committee turned up, summonsed by occasional louder detonations within the bowls of the complex, they found us helmeted and safety goggled behind sandbags and an upturned table.

A very long stick was connected to the heavy steel apparatus through a hole in the very stout wooden box that enclosed it against shrapnel. Turning the stick opened a tap that initiated the process.  Sometimes the box would then leap into the air.  For some trivial reason about it looking 'Heath Robinson' they ordered us to desist! 

Later we turned our attention to another idea that involved, as a side effect, consuming a foam containing, among other things, an isocyanate in a very high temperature furnace.

Although we assured the committee that it was properly ventilated and it was unlikely that at these temperatures any cyanide gas would be released into the Lab, or the London air, they called a halt to that too; but not before some nice samples had been made.