Black Powder Firecrackers for Special FX?

[OblivionFall]

Hi there,

 

I'm looking to make a couple of Black Powder salutes as apposed to Flash Powder for an upcoming film because:

 

1. They make more, white smoke

 

2. They aren't very loud

 

3. They aren't as dangerous

 

The idea is that it will be three guys in full military gear with ear plugs in a "desert warzone" (sand dunes in the middle of nowhere,) and about 50 feet behind them I will have three or four Black Powder salutes packed into the ground with sand over them to simulate mortars exploding. I will also use a couple for "grenades" and other explosions throughout the film. I will add in a big explosion sound effect afterwards when I video edit it.

 

How should I go about this? What differences do I have to make with Black Powder salutes as apposed to KNO3:Al:S Salutes? I want to have nothing in them that could be a projectile.

 

I'm Looking to Make Something Like This: https://www.youtube.com/watch?v=V9AkvnSYO8s&t=01m00s (without being as close to the explosions.)

[SideGlance]

bp needs good confinement. Run some trial tests and film them.

[OblivionFall]

bp needs good confinement. Run some trial tests and film them.

Will do. In fact, I'll try a bunch of different variables to find the best possible BP firecracker and post it on vimeo for you guys.

[nater]

BP Maroons are common in Germany. They use chipboard cut and folded to form a cube. The cube is filled with BP, fused with time fuse and spiked solid in each direction. Obviously they are not as loud as a flash report, but they are a nice unique effect.

 

We do mortar hits as a special effect. I cannot disclose our method, but I will warn you to sift the sand and earth used over them. It is imperative that the area is free of any debris. This includes rocks and dirt clumps which could injure / kill an actor.

 

You do have a close prox pyrotechnics license, product with the appropriate UN numbers, local permits, etc .. correct?

[OblivionFall]

BP Maroons are common in Germany. They use chipboard cut and folded to form a cube. The cube is filled with BP, fused with time fuse and spiked solid in each direction. Obviously they are not as loud as a flash report, but they are a nice unique effect.

 

We do mortar hits as a special effect. I cannot disclose our method, but I will warn you to sift the sand and earth used over them. It is imperative that the area is free of any debris. This includes rocks and dirt clumps which could injure / kill an actor.

 

You do have a close prox pyrotechnics license, product with the appropriate UN numbers, local permits, etc .. correct?

No I do not have the license. I probably would know the answer by now if I had a permit. That's why I'm interested in doing this safely and not having too loud of explosions. After all this will be in the middle of nowhere and considering video effects these days I'm sure it could pass as a video effect. It is going to be filmed on big sand dunes, which means that there is nothing that could potentially harm anyone but I will be sure to sift it. It will also be 40-50 feet away and I will not use any materials that could be a projectile for added safety.

[MrB]

1. They make more, white smoke

 

2. They aren't very loud

 

3. They aren't as dangerous

 

1. True, i suppose.

 

2. Then your doing things wrong. BP is as loud as anything else. It just needs to be treated right.

 

3. Define "dangerous". BP is going to ruin your life, if you start treating it like it's "safe to handle". Kill someone, or tear limbs from a body.

 

Just saying. While BP is a much better alternative then flash, in many circumstances, never mistake it for being "safe". Either way your still holding a big venomous snake by it's tail.

B!

[OblivionFall]

1. True, i suppose.

 

2. Then your doing things wrong. BP is as loud as anything else. It just needs to be treated right.

 

3. Define "dangerous". BP is going to ruin your life, if you start treating it like it's "safe to handle". Kill someone, or tear limbs from a body.

 

Just saying. While BP is a much better alternative then flash, in many circumstances, never mistake it for being "safe". Either way your still holding a big venomous snake by it's tail.

B!

Well of course any explosive can be dangerous. What I mean is BP is not as loud for the amount of smoke it produces.

[Arthur]

Leaving you to comply with your statute law and codes.

 

BP is just as effective as flash or HE, just different! BP needs confinement, so some form of string bound maroon is where I would start. My local SFX company supplies quarter, half and full pounds of BP in string bound cases that's like a three, four and five inch cylinder shell, fully wrapped in string, with an igniter ready fitted.

 

I'd want the maroon in a hole and all the dirt sieved to remove any big bits.

 

enjoy

w.youtube.com/watch?v=VSvxR66BPaA

 

then ask questions (but there was a lot of HE used that day.

[Ubehage]

As you propably know, BP will almost always burn at a steady rate - differenting from batch to batch.
In order to make a good boom, you need to confine the BP really good. More than you need with standard flash.

 

When BP is confined, it will burn extremely fast (which is what you want). But as soon as the pressure overcomes the confinement, it will burst and any remaining BP will continue to burn at the steady rate.

You might need to experiment with getting the right confinement.

[insutama]

I have always been interested in black powder maroons untill today i never knew what they were called i have just seen vids on youtube about them. How exactly are they made ? and how do they get it to hold the pressure. you said its chipboard so im guess thats particle board. Im guessing you dont want to use nails to hold it together lol so how would you hold it together ? woodglue then string ? also how come they use time fuse and not normal visco for them ?

[Arthur]

Chipboard in this case will be a cheap heavyweight greyish cardboard. Absolutely certainly there will be no wood or pins of any sort will be in there for projectile problems. The board would typically be used for backing pads of forms. or separating NCR paper sets of forms.

[insutama]

ah okay that makes sence how did they hold it together other than the string

[OblivionFall]

ah okay that makes sence how did they hold it together other than the string

Yes they spike them like shells with Hemp or Cotton string.

[nater]

Do you know how to cut and fold Paper into a cube? You start with a cross shape. The seams are closed with tape. Fill the cube, close the lid, add the fuse. It is spiked solid in each direction with the strands touching each other.

 

https://www.google.com/search?q=fold+a+cube&safe=off&client=ms-android-att-us&source=lnms&biw=360&bih=615&tbm=isch&sa=X&ved=0CAYQ_AUoAWoVChMIlbax2OiSxgIVhpUNCh2vAw-U

Edited June 15, 2015 by nater

[mikeee]

You can use a cardboard tube and end discs for a BP maroon, you just need to solidly spike

the entire shell with vertical and horizontal spiking.

[insutama]

what exactly is spiking the shell i have heard that term alot on here i know it means wrap string around it but what else does spiking a shell consist of ?

[nater]

Traditionally, it is only cylinder shells which are spiked. Since the shell casing is several turns of kraft, the spiking provides the confinement needed for a good break. In addition to the confinement, good spiking helps the shell become very solid, preventing it from compressing under the forces of lift and flowerpotting.

 

The traditional method is to saturate thin twine with wheat paste and apply the spiking. The paste helps the string bite into the end discs so they stay in place. As the pasted string dries, it also shrinks which further helps the shell stay nice and rigid. It is neat to feel how the shell changes during the spiking process.

Edited June 15, 2015 by nater

[insutama]

very intresting thanks for sharing that

[Ubehage]

what exactly is spiking the shell i have heard that term alot on here i know it means wrap string around it but what else does spiking a shell consist of ?

https://www.youtube.com/watch?v=w70L6-4aCRc

[insutama]

perfect thanks i now know what spiking is

[Arthur]

A string bound maroon is like a cylinder shell but with 100% string spiking -all the item is covered in string. Usually the string is wet with glue and then allowed to dry, possibly the glue has colour (ink or paint) added, my wholesaler makes them black.

[schroedinger]

There are some things too add.

Most bp crackers i europe are made quite different compared to the cubic salutes described here.

 

E.g. for a 15 mm i.d. salute a 5 cm clay plug is pressed into a tube. Inside this runs a visco. Followed by 2 -8 g bp, followed by a 2nd plug of 5 cm clay. The clue is that the bp gets only slightly compressed as the bp is only slightly tapped once and pressed with a big ammount of clay.

 

For the cubic type, the easiest way is to get a pattern of the cube with some areas for gluing it together. Assemble the cube, fill with bp or h3, close it. Cover with 3-5 layers of gummed tape followed by a spiking in direction of all three axis.

[deer]

Just a thought. Instead of actual soil can't he use some fine, fire retardant powder, for greater effect and apparent mass ejection?

E.g. mostly cover the charge with clay powder, milled sand, sodium bicarbonate with some dye etc. and just very little soil to mask the powder.

Maybe even pack this in tube to help with impressive vertical ejection.

[OblivionFall]

Just a thought. Instead of actual soil can't he use some fine, fire retardant powder, for greater effect and apparent mass ejection?

E.g. mostly cover the charge with clay powder, milled sand, sodium bicarbonate with some dye etc. and just very little soil to mask the powder.

Maybe even pack this in tube to help with impressive vertical ejection.

Yeah if you guys could give me some ideas for powders to use that would be great.

 

I don't have lead media and I need to film this within a week so I was thinking of just using KNO3/Al/S flash in a mortar-type tube with the fuse going into the bottom side with one end plugged well and the other end just a cardboard disc and powder on top of it.

[insutama]

I wouldn't use flash in a mortar stick with bp for the mortar