3 replies to this topic

[exat808]

Looking for as much info as possible please regarding flash comp made from Boron/Potassium Nitrate

 

Pressures

Ignition temps

Critical mass

Ability to burn to detonation or not

etc etc

 

Whatever info you have specific to this substance will be greatly received.

PM if you want it kept discreet.

Needed ASAP please.

 

Thank you in advance

 

Oh - academic references where possible - no conjecture please - just plain facts!

Edited by exat808, 08 September 2015 - 07:01 PM.

[samboradford]

Shimizu makes reference to a 75:25 mix of amorphous boron ( note the crystalline form is not suitable) and potassium nitrate in Fireworks, the art, science and technique. 

 

He goes onto to state :

boron has a specific gravity of 2.35, melts at 2l60°C, boils at 3650°C..... A mixture of amorphous boron and potassium nitrate in a ratio 75:25 burns rapidly with a brilliant green flame at very high temperature.The green colour comes from BO2 band spectrum. The boron mixture is used as an ignition composition in place of thermit, and the difference between the two lies in that the former ignites other compositions with its high temperature flame but the latter mainly with its high temperature liquid cinder. The boron mixture ignites very well from a relatively weak heat source such as a black powder flame.

 

That may help you get started ?

[spectrum]

Boron based compositions featured to a lesser degree in defence formulations developed by the MOD principally from the early 1950's through to the mid 1960's. The high cost of the element presumably precluded it from use in any area where common sense economics had any influence. The mixtures from memory and experience were used in primings, developed at Woolwich and later Fort Halstead they were listed in the low numbers of the SR register from SR 41 to SR 44. Further entries up into the SR 90's reveal the continued use of Boron but with other oxidising agents and almost exclusively in delay compositions - these entries relate to delays, either gasless or near gasless 

 

For the nostalgic of us all, they really do hark back to a golden age where they competed with bakelite for inclusion in the approved materials list.

 

The compositions were employed in high altitude functioning stores. Besides one "prick sensitive composition" I never recall these being that exciting - other than to the purchasing department!, I rescued the last of the stock from the bonfire before Astra disappeared - came across it a little while back with notes I made on the label at the time "washed and dried". At a fraction of the price R.O. / MOD favoured Silicon having explored throughout the same period Zirconium (£!!) and various oxidising agents.

 

Safety certificates were issued which did not make for exciting reading, depending of course on the choice of Oxidant - as I write this I am reading the entry on SR 61 which shows an F of I - 20-35 and F of F 100-100-60. Three Shredded Wheat before mixing that one maybe!

[Arthur Brown]

Once used for gasless delays, because the reaction is gasless the rate of reaction isn't pressure dependant hence they perform at altitude.