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Member Since 13 Sep 2007
Offline Last Active Apr 28 2018 12:39 PM

Topics I've Started

Munroe effect - practical demonstration

26 January 2018 - 12:45 AM

Ref - History of shaped charge effect the first 100 years author Donald Kennedy

status- unclassified  general distribution


Dr Munroes experiments in 1888 pressing letters into a gun cotten cube then exploding it in close proximity to a steel sheet resulting in the letters being clearly imprinted into the steel sheet was the start of research into shaped charges .


In order to demonstrate this in a school or public lecture the ideal explosive is a stoimetricmix of hydrogen and oxygen  this is easily acheived by electrolysis  of  dilute sodium carbonate solution  This works better than electrolysis of water as the sodium carbonate in solution results in an increased conduction and current flow at low safe voltages . The steel sheet is replaced by a flat layer of plasticine on a thermostatically controlled heated mat .As the temperature of the plasticine is increased it becomes softer so by varying the temperature of the plasticine we can change the amount of force nessecary to imprint upon the surface. A flattened leaf is placed on the surface. The surface is then covered with strong detergent solution or bubble mixture. The hydrogen/oxygen mix from the electrolysis unit output pipe end is pressed gently into the bubblemix so that the whole surface is covered with a layer of bubbles-our explosive. The explosive charge is fired by a lit taper . This results in a loud satisfying bang  that delights the audience .By careful "tweaking" of the plasticine density clear  explosive formed prints of the leaf or a coin can be stamped into the plasticine.

Plaster of paris or dental plaster can be used to take a mould of the prints to form a more permanent record of the results .


Hydrogen oxygen bubbles can be fired on your hand without damage this may have potential for stage special effects???   

nitrous oxide and bitumen motors

18 October 2015 - 04:23 PM

 bitumen is cheap and readily available from many larger builders merchants and one block purchased will be more than a lifetimes supply .

It is easily casteable when hot. There has been a lot of research using it as a fuel with a solid powdered oxidising agents including ammonium perclorate  (ref  gilsonite )

it functions well  as a reliable  fuel  when oxygen or nitrous oxide is blown through it ,

I am hoping to obtain a large nitrous oxide cylinder shortly to research burn rate and thrust .

I have oxygen on tap as a comparison.

The reason for this sudden interest is I have found a source of small disposable cylinders of nitrous oxide .

Thee cylinders are slightly larger than the disposable co2 cylinders used for soda syphons

They are purchased in packs of 5 or 25

Using these cylinders for rocket motor research would be costly hence the larger nitrous oxide cylinder I propose to rent for a year .

The question is  can a viable model rocket be launched using a disposable NO2 cylinder and bitumen motor????.


If this work fails to produce a viable model rocket engine due to size/weight  thrust and duration constraints  I have the basis to build a variable controllable thrust large rocket motor for a bicycle or trike ride !!!!

if anyone has any  tech info  or would like to take part or borrow the cylinder or  for example does anyone know how oxygen and NO2 compare as  research using  bitumen and oxygen is a very cheap option as I have a large oxygen bottle and regulator for gas cutting on the workshop outside wall. do post or pm







a safe legal location for amateur experimentation and testing in N W Leicestershire

17 September 2015 - 09:58 AM

I am considering erecting a number of very small drab green sheds in our remote field location there is electricity available . Eventually i will have milling shed, star roller visco machine?  , hydrualic press , chemical store ,black powder store . testing area   etc etc  all in place for safe amateur  use . fully alarmed linked to 24 hr monitoring  security company . there will also be a goose shed , they are great guards .


It will be  a lot of work for me to build this and operate it alone . Is there anyone out there who would like to come along and use this facility??? It is much more enjoyable working as a group sharing ideas.


Would anyone like to join me in this venture???? . I do not want your money!!! . for example if you were to put up a shed it would remain yours ,sited free and you could take it away again any time you wished to.  Ive a whole load of strong ex mod lockers you could lock away tools etc in with your own lock . theres plenty of space available .


also if you are in the midlands and would like to have a pyro orientated evening either hands on or just a social /drinks  time singular or regular event please post below .If you dont have access to post messages on this forum yet then  text or call 07976 818006 .


Do pyro enthusiasts exist in the midlands or am I the last one out here!!!


potassium perclorate is listed as explosive precursor

05 February 2015 - 05:27 PM

from 2016 we need to have used up any potassium perclorate we have in storage as on 2nd  Mar 2016 it becomes illegal to own it, or we need to obtain an epp license to purchase and hold stock of it.This is because it is listed as an explosives precursor.  we should already have an epp license if we wish to    purchase it or the seller faces 2yrs in prison. The application costs £39.50 for 3 years. This does not apply to business users . . further info is in    licensing for home users of explosive precursors on home office web site.                                              

From the web site info listed substances are

Concentration threshold
  • hydrogen peroxide:12% w/w
  • nitromethane: 30% w/w
  • nitric acid: 3% w/w
  • sodium chlorate: 40% w/w
  • potassium chlorate: 40% w/w
  • sodium perchlorate: 40% w/w
  • potassium perchlorate: 40% w/w