15 replies to this topic

[7th Air Cav]

Hi all, i'm new to the forums but have done a bit of pyro work over the last year or so. I am part of vietnam war re-enactment group & we usually use the pre-made fireburst b**bs to create a napalm type explosion with fireball.

I was wondering if anyone know what liquid fuel you would use to get a bigger effect. I was told by a guy that does pyro for another group that they use the fireburst b**bs & some liquid fuel to enhance the effect but he would not tell me what it was or how much he uses, i think this has more to do with the old saying "mines better than yours" lol.....

Any help would be appreciated as it seems you guys know what your talking about

Many Thanks

[marble]

No need for liquids

http://www.skylighte...sp?Item=120#art

Edited by marble, 09 June 2008 - 08:24 AM.

[phildunford]

'Flame balls' are usually made by placing a plastic bag full of a 50/50 mixture of petrol & diesel on top of an explosive charge.

In the movies, they use HE (which is a no-no on this forum) but you can get pretty much the same effect by using a bag of black powder instead.

Obviously, it's a pretty dangerous process and would advise you to experiment small-scale at first and keep your guys at a safe distance!


PS

Marble is also quite correct and this method is alot safer! You pays your money and you takes your choice...

Edited by phildunford, 09 June 2008 - 08:30 AM.

[7th Air Cav]

'Flame balls' are usually made by placing a plastic bag full of a 50/50 mixture of petrol & diesel on top of an explosive charge.

In the movies, they use HE (which is a no-no on this forum) but you can get pretty much the same effect by using a bag of black powder instead.

Obviously, it's a pretty dangerous process and would advise you to experiment small-scale at first and keep your guys at a safe distance!


PS

Marble is also quite correct and this method is alot safer! You pays your money and you takes your choice...

So i guess you could try it with a small fireburst b**b & put a small bag of the mix on top to see how it goes. Were lucky enough to have a huge outside field to test in & i always make sure we are clear of anything dangerous & no one else has a key to my firing system.

[phildunford]

So i guess you could try it with a small fireburst b**b & put a small bag of the mix on top to see how it goes. Were lucky enough to have a huge outside field to test in & i always make sure we are clear of anything dangerous & no one else has a key to my firing system.

I'm pretty sure that would work.

All these methods work by the 'charge' doing three things:

1) Setting fire to the fuel.
2) Propelling it upwards.
3) Dispersing it in the air so it burns quickly.

Use a metal can (with no top!) so the effect is contained and directed upwards.

Good luck! (and welcome to the forum)...

[7th Air Cav]

ok excellent i'll try that. The fireburst b***bs come in a plastic tub, so i'll put that in the can & add the mix in the bag on top of it.

Would you say 100ml was a good amount to start with?

[pyrotrev]

I suspect you might want a bit more - my SFX supplier starts at 250ml for "poly bottle" flameburst units. PS to keep things tidy should this be in the SFX section?

Edited by pyrotrev, 09 June 2008 - 12:05 PM.

[Arthur Brown]

Fireballs are a topic on their own! I've seen them done with 5 litres of petrol/ kerosene/ diesel maybe mixed with old lube oil BUT at a fair range. I suspect that the war film effects are done with 5 - 500 litres of fuel! Filmed from several angles and shots cut in for effect.

I suggested that a group of us do the BECTU SFX course, Perhaps we should look again at the possibility To book a course we need a group! It's three or four days on a farm with skilled SFX trainers doing HE and pyro SFX. Accomodation is provided.

[7th Air Cav]

I suspect you might want a bit more - my SFX supplier starts at 250ml for "poly bottle" flameburst units. PS to keep things tidy should this be in the SFX section?

What do you mean by poly bottle flameburst units?

[Arthur Brown]

Are you in the UK?

DIY fireballs need some form of propellant which usually being gunpowder/blackpowder is a 1.1 classified HE therefore you need a 1.1 rated and licensed store for your supply.

Commercial fireball pots, by virtue of their packaging become 1.3 which is easier to acquire and store and hence use.

Clipped from a supplier catalogue;

Fireburst Ground Charge, 500ml, 750ml, 2.5 ltr, 1 gallon sizes, poly' bottle, electric ignition. HZ: 1.3G. UN: 0430

[portfire]

gunpowder/blackpowder is a 1.1 classified HE

????? I can see how BP can be classified as 1.1, but HE ??


555 timing anyone

Edited by portfire, 10 June 2008 - 06:33 AM.

[BrightStar]

????? I can see how BP can be classified as 1.1, but HE ??

1.1 is simply 'Substances and articles which have a mass explosion hazard' and BP certainly does in sufficient quantity. The fact that it is still classified as such in small quantities might be a bit of social engineering on the part of the powers that be. They just don't really want us to have it lying around.

As I understand it, BP is class 1.1D, the same as most secondary HE:

http://www.ribbands....ages/hazcat.htm

As I read MSER, you will need an explosive cert to buy black powder but may store up to 10Kg without registration.

Back on topic, try a 50g BP maroon under a freezer bag filled with 500ml petrol/diesel mix placed in a small 8" long, 5" diameter steel bucket (burried in the ground) for a 30' mushroom cloud of flame...

Edited by BrightStar, 10 June 2008 - 10:07 AM.

[portfire]

1.1 is simply 'Substances and articles which have a mass explosion hazard' which BP certainly does in sufficient quantity. The fact that it is still classified as such in small quantities might be a bit of social engineering on the part of the powers that be. They just don't really want us to have it lying around.

As I understand it, BP is class 1.1D, the same as most secondary HE:

http://www.ribbands....ages/hazcat.htm

As I read MSER, you will need an explosive cert to buy black powder but may store up to 10Kg without registration.

I understand that, If it's contained for transport then it would be classed 1.1, but didn't think it would be classed as a HE. If it was loose powder meal or granulated, then I would say it would be 1.3. Obviously in larger quantities this would be differant ?

[BrightStar]

No, it's not HE, but unfortunately is still 1.1. The storage and transport concessions given for 'shooters powders' and reenactment make it a little more usable than it might otherwise be.

Here's a short vid of a medium sized fireball I tested some time ago using the above configuration:

Fireball - 50g BP lifting 500ml fuel (Divx avi, 795KB)

This was filmed at around 50m range and you could really feel the heat. Certainly not a close prox effect...

Edited by BrightStar, 10 June 2008 - 09:41 AM.

[7th Air Cav]

Are you in the UK?

DIY fireballs need some form of propellant which usually being gunpowder/blackpowder is a 1.1 classified HE therefore you need a 1.1 rated and licensed store for your supply.

Commercial fireball pots, by virtue of their packaging become 1.3 which is easier to acquire and store and hence use.

Clipped from a supplier catalogue;

Fireburst Ground Charge, 500ml, 750ml, 2.5 ltr, 1 gallon sizes, poly' bottle, electric ignition. HZ: 1.3G. UN: 0430

Yes i am in the UK.

We would normally just buy the pre-made ones in the plastic bottles with the electronic igniter already in it but the idea was to make the effect bigger without increasing the cost by too much. We were thinking if we used the small pre-made one with the petrol/diesel mix on top as said by Brightstar then the size of the effect would be tripled just with the addition of the fuel. I also have the maroons that you spoke about & can see that as an even cheaper alternative.

Don;t get me wrong though, i dont want to put anyone at risk just to save a few £'s........

If you think this is the best way to go then i will get a morter made up.

Cheers