73 replies to this topic

[cplmac]

I've always been partial to creamoras, but there are a lot of different powders you can use to achieve the same effect. I make mine in a five gallon bucket, basically I tape a squib to the inside bottom of the bucket, add about two cups or so of 2FA, drop in a paper plate over the BP and fill the rest of the way full with powdered calves milk. Makes a large fireball, and a decent concussion. You can feel the heat waver from a couple hundred feet away. Nice rolling fireball. We have made similar effects with a five gallon bucket, gasoline and a shape charge under the bucket, much bigger louder and hotter fireball.

[Steelrat]

i was working on another Highlander movie number 5, doing the model pyrotechnics for an exploding Tower in the Film thought it may be of intrest.
i used 30 foot of 5grm detonating cord with a number 8 detonator , one 50gram black powder maroon hard case, 1 kilo of Fine fullers earth, the model was 40 foot high, with a centre core made from a long scaff pole weighted with 25 kilo stage weights at the top, creating a free falling structure that would collapse, as the first 2 main charges was detonated. thought you would be interested in the result, pictures taken from my video cam, actual movie cam speed set at 120fps, film will be out later this year.

http://img352.images...odelpyrokp9.jpg

[Caramanos2000]

I was thinking of making something along the lines of an explosive rope. I thoughmaybe take some soft clear about 1/4" tubing which is very cheap and fill it with flash and sealing the ends. Maybe 4 or 5' at a time. Shouldnt take more than 30g of flash. I wonder what it would look like?

[MFX]

Hi im a SFX pyro designer.
thought you would be intrested in a Propane gas explosion i created for the met police training video,

Hi Steelrat, or should I say Phil ;-) Martin here. Got anymore work coming up. I'm in the process of rebuilding my propane woofer. I'm thinking of making a control system that automatically measures the pressure in the reciever so I can set it to produce multiple quick small fireballs or less frequent large ones by adjusting both the reciever pressure and solenoid valve on/off time.

Edited by MFX, 21 May 2007 - 09:38 PM.

[Steelrat]

Hi Steelrat, or should I say Phil ;-) Martin here. Got anymore work coming up. I'm in the process of rebuilding my propane woofer. I'm thinking of making a control system that automatically measures the pressure in the reciever so I can set it to produce multiple quick small fireballs or less frequent large ones by adjusting both the reciever pressure and solenoid valve on/off time.

Hi Martin , sorting out some stuff with mattes and Min atm, will keep you informed stay in touch
Phil

[Richard H]

Bickford, I deleted your previous post because from the way you described it, it did not appear to show a safe system of work! We do not concern ourselves with pipe b**bs here, and they have no place in SFX. To produce fireballs it is more customary to use a directional mortar such as a C or V pan, into which a black powder strung-bound maroon is placed below a bag of several litres of fuel (Typically 50 / 50 Petrol / Diesel mix). When the maroon goes off, the mortar pan channels the rapidly expanding gases upwards / outwards, igniting the fuel and distributing it as a fine aerosol where it continues to burn in the air.

Another technique is to use a flash powder maroon in a light cardboard or POLYTHENE / low-density case (non-fragmenting!). A supporting collar made from cardboard or a plastic bucket is used, into which the bag of fuel is placed. The end result is similar to the blackpowder maroon with the difference that a chest-thumping report accompanies the fireball. I have used both these techniques at professional displays. You NEVER use high density casings like PVC, and you certainly never-ever use glass bottles to contain your fuel!

Please think twice before you post on this forum, the quality of information posted here is of paramount concern to all of us.

[portfire]

I apologize for my post richard,although i was voicing my concern, i should've worded it differently.

dean

Edited by portfire, 08 September 2007 - 03:34 PM.

[Richard H]

Dean, I was not having a go at you. I just wish to remind some of our less frequent posters of best-practice techniques.

[RangerOfFire]

I believe they're suggesting you make something like in the picture below. The idea is the maroon breaches the bag/bottle and then the bp coating ignites the fuel. The mortar directs the blast upwards and also helps keep you safe.
You should not put visco fuse over a plastic bag (or possibly bottle) (as in have a fuse trailing out the top) as it may ignite the fuel.

Disclaimer: By viewing the picture below you hereby relinquish from liability both the UKPS and RangerOfFire from any legal action as a result, direct or otherwise, of following the information contained in the picture below. The image is © RangerOfFire 2007.

[BrightStar]

One method starts with a 50g black powder maroon (e-matched, string bound cardboard case - well pasted in) in the base of a large steel can - approx 6" id by 10" length. This must be buried in the ground 3/4 of its length for safety - even then the can will visibly deform in use.

A plastic sandwich bag containing 500 ml of petrol & diesel mix is then carefully placed in the can and the whole thing covered with foil for rain / spark proofing.

In displays I can confirm that this gives a very loud bang and a 50+ ft high rolling ball of flame.

Frankly though, this is absolutely NOT a beginners project - there are just too many hazards. A good star mine is more exciting and predictable.

[MFX]

I have seen that its possible to use gaz to make special effect fireball.

Not gaz in bottle but charge of gaz ...

who know this method ? and how its run ??

Thanks !

BICK

You use what's called in the trade a "woofer" or "Propane mortar/cannon" (note woofer can also relate to the same hardware used as air cannons used to hurl debris, so propane mortar is probably a better term). They're not particularly cheap to make though (a lot depends on whether you're happy with a "single shot" device or want to fire it multiple times)