19 replies to this topic

[pyrotrev]

The reason for a bit of air space in flash reports is to make sure the stuff doesn't pack down too tight, if it did it would just burn rather than explode. The normal rule of thumb seems to be to fill the container 60...70% full.

Edited by pyrotrev, 10 November 2008 - 01:32 PM.

[Gigantic Crab!!!]

On closer thought do you mean 125ml not 125mm as a 5 inch canister salute would knock you off your feet (well maybe not but it would be seriously powerful)

Gigantic Crab!!! has used 5" diameter ground maroons. He recalls that they are a little on the "pokey" side.

[Mortartube]

And you should know Gigantic Crab. You have more feet to stabilise you than us mere humans.

Pokey is a lovely word and is very apt.

125MM not ML is correct. But as previously mentioned the bottle is about 1/8th full of flash.

[kcnkickthecat]

Perhaps the extra confined air would be super-heated in a fraction of a second, similarly to when lightning passes through air. Maybe that would increase the air-blast effect?

[cooperman435]

I also think it is a contributing factor that as a comp combusts inside a part filled container it is allowed to expand slightly before the container breaks. This will allow more of the comp to be ignited whilst inside and therefore under pressure to assist in the burn rate.

Although commonly flash is believed to create no gas when burnt this is a slight misconception. Whilst the products of the reaction are solids, when they are superheated at the point of combustion they are given out as gas otherwise there would be no "push" from the powder at all.