Instructables

Cheap, reliable, easily mass produced squibs for gunshot fx

Picture of Cheap, reliable, easily mass produced squibs for gunshot fx


I recently spent a lot of time researching squib designs for a short film that I am working on. I found that most designs were unreliable, unworkable or expensive. I did find several designs that mine ended up being a variation of which use model rocket igniters. But for my purposes, which involve a lot of squibs, this would be too expensive. I decided to find out how to make my own igniters and came across this great site to which I owe a great debt of gratitude to. Using their recipe for igniter goop and the inside of an old hairdryer, I was able to make igniters tat cost almost nothing.

!!!WARNING!!!

Please note that I am not a professional anything, let alone a pyrotechnican and I take no responsibility for anything that happens from you trying to do what I have done. This is a very dangerous project if not done properly and all possible safety precautions should be taken when attempting it.

That being said...
 
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Step 1: Materials and tools

Picture of Materials and tools
The basic materials for this project are as follows:

For electronically ignited firecracker
1. Nichrome wire (from hairdryer)
2. Black powder
3. Acetone
4. Ping pong balls
5. Black cat or similar firecracker

For blood pack:
1. Fake blood
2. Condom (unlubricated for god's sake!)
3. Cardboard
4. Duct tape

For Battery pack:

1. 3 9v battery clips (sorry, I only had two for the pic)
2. alligator clips
3. Insulated wire

You will also need, along with general tools, a rock tumbler and a bunch of lead balls about 1 inch in diameter to grind down the black powder. These are probably the biggest expense. I happened to have them around so it worked out for me. You could use a mortar and pestle but I personally would not feel safe doing that. It only takes one spark to set off black powder.

If you can find another, safe alternative, please post.
Will six button cell batteries work? Also, how powerful is the explosive? I'm planning to make a dye pack, and rig it to a wallet, so that it'll explode through the leather of the wallet, and carry enough dye to stain the hands of the would be thief.

The voltage isn't as important as the amp rating. The more current going through, the faster the heat buildup. 9V batteries are actually one of the worst choices for this project (no offense op) because they provide lower current than AA's do. Using a few AA's in series will also give far more uses, since one AA has about 4x the capacity of a 9V.

tastysoup (author)  TheSquibDyePacker5 years ago
I don't think button cell would do it but maybe if you had enough. I have found that at least two 9vs are needed to get a reliable blast. Thing about explosives is that the force isn't just dependent on the amount of actual fuel. The compression due to the amount of air space around the fuel as well as the materials being blown through are a big factor. The force of the explosion is going to take the path of least resistance and hit that path with most of its power. That's how shaped charges work. I doubt that a black cat could blow through the leather of a wallet but someone who knows how to shape a charge might be able to figure out how to make it work. If you used a higher powered explosive it wold probably be dangerous. I would suggest finding a way to have the dye pack on the outside. Good luck!
Well, I know that a button cell is 1.55v each, and 6 times 1.5 is 9, I don't know much about electricity, but would 12 to 18 have enough amperage or whatever? As for the leather, I suppose I could score the back of the inside , so that it'll be weaker, or separate the layers, and put the dye in there. I was thinking shape charges too. Although, the more I try to sketch it out, the less compact it seems. I still haven't decided on which switch would work in the case of a thief opening the wallet to take the money, it would have to be inconspicuous. How long does this stay "armed"? is it possible to leave it on for long periods?
By no means do i want to rain on your parade, But this just sounds like a generally terrible idea...

If your wallet is being stolen and you somehow fit a wireless detonator into your wallet, and activate it, what then? His hands are dyed, But so is your money and information cards!

It seems like a waste of money, and completely unnecessary...
Please excuse my flames
That's the point, the money is now suspicious, and could be traced to the thief. As a general rule, places don't accept stained cash, due to the knowledge that dyed money is stolen money. The point is to get them caught, this is more useful in places like school, and work, but could find some use outside of such institutions.
I HIGHLY recommend that you check with your local law enforcement before doing what you've outlined. I know where I live, you would be liable for any injury caused by your device, resulting in medical bills and possibly a lawsuit from the person injured. This also would bring into evidence exactly what you did and I suspect that building a 'remote detonation' device is illegal, not to mention they would also probably bring up that you knowingly transported a firework(in my state and the neighboring states that is illegal without special permits punishable by a $1000 fine plus up to 1yr in jail for *each* offense...2 black cats would be 2 offenses), opening you up to criminal charges there... At that point it really becomes a game of 'just how bad do we want to f this guy in the a' because they could then easily get a warrant and search your home for 'bomb making materials' (this also adds more to the above offense if you have any leftover fireworks that are illegal) along with possibly searching your computer, finding history and shortcuts to things like this instructable could be portrayed as conspiracy to do the harm to the person injured, next thing you know your on trial for domestic terrorism.... I'm not saying all of this will happen to you, just illustrating just how easily and quickly things to spiral out of control if someone got hurt and one of the cops decided he didn't like you...
tastysoup (author)  RawLiquid4 years ago
Hi, welcome to Instructables. I think that everybody is aware of the at-your-own-risk nature of these projects. I mean, come on, have you seen the instructions for making a rail gun out of disposable cameras? http://www.instructables.com/id/How-to-make-a-RAILGUN!/
08motooley9 months ago
could you not use a wooden rolling pin and roll over it slowly or am i just being thick?
tastysoup (author)  08motooley9 months ago
That might work nut I'm not sure if that would get it fine enough or how safe it would be. In theory, wood would not create a spark but I haven't tried it and frankly, I am more comfortable with it happening automatically at a distance.
mad_hatter2 years ago
I tried your squib backed with a 1/8" thick, scrap piece of ABS. The construction was ABS-Charge-blood pack. we hot-glued the charge to the ABS, then used packing tape, just on the edges of the condom. After several tries the only drawback was the heat (which was very tolerable) and we fixed that with a pad of gauze. The condom was thin enough to prevent directing the energy inward, and I wouldn't reuse the ABS, but overall it fired safe and effective. Great job and thanks!
Prof. Yummy4 years ago
I've been shooting blood out of people for a few years and I've worked on several films with experienced stunt and special effects and pretty much the consensus is that no one uses explosive squibs anymore. It's too dangerous and the smoke gives the effect away. Compressed air is the only way to go. I have been perfecting a method of multiple gunshots using an paintball co2 tank running to a manifold with cheater valves. It seems the problem with you squib is that the explosive is on the outside of the quib, so it doesn't force the blood out of the wound. Traditionally the squib is under the blood pack. In that case you wouldn't use cardboard for obvious reasons. I have seen leather pads or even a full leather cuirass used for multiple shots. I will be posting my own instructable on air squibs shortly.
I'd love to see that. I do stunts myself and always love to see other peoples way of doing things. Like Aikido, so many ways to do one thing and everyone has their own preference.

Kindest Regards.
steampirate4 years ago
I visibly cringed when I saw that you were using a firecracker. The ideas however are very good. I never would have tried using a condom to hold the blood. In answer to your question about black powder, it is perfectly safe to use a  mortar and pestle to grind it however your crude ball mill would work better because it creates a finer grain and mixes the powder better.

jonrb4 years ago
Great instructable!
Three questions:

1. Can you show me a picture with the firecracker next to a ruler? (i live in Switzerland, all of the fireworks are different!)
2. If i replaced the cardboard with molded and hardened plastic (or a curved metal sheet), would it be safe to put the explosive behind the pack?
3. Is toaster wire the same as hairdryer wire?

Thanks!

tanniynim5 years ago
I haven't tried it recently, but model rocket ignitors should work instead of making your own. Yeah, it costs a little bit extra, but then you aren't playing with black powder and you don't have to find a tumbler (which is also expensive.)
tastysoup (author)  tanniynim4 years ago

Yeah, my first attempts were with rocket igniters but with the number of squibs that we needed the cost was prohibitive. Rocket igniters don’t seem too expensive individually but at fifty cents to one dollar each, it quickly adds up. I think that each of these probably cost a penny or so when all is said and done.

byoho tanniynim4 years ago
Model rocket ignitors tend to have a short delay.  Might be an issue depending on how your scene is being shot.  I prefer to have the effect go off the moment I push the button, so I don't use them.  Tried 'em, don't like 'em.
Excellent! I loved the Condom idea and the videos
5*
tanniynim5 years ago
Did you wire your 9v in series or parallel? It looks like you've got them in parallel, but I can't say for sure.
tastysoup (author)  tanniynim4 years ago
Yes, parallel.

How would you? What? Its a 9V With a connector leading to the nichrome!
Thats a simple series, Cant think of it being a paralel.
Then again Im totally stubborn and probably wrong

thing 24 years ago
 Wouldn't a fire cracker hurt???
oOH IM going to wire up remotely so a camera man can set off the squib when he wants to
tastysoup (author)  stephenniall5 years ago
That could work
kicker1095 years ago
would the "blood" run out faster or squirt all over the place if you had the explosive behind the blood pack
pdub775 years ago
what website are you referencing? 'I found this site which gives great info on electronic fireworks detonation'
tastysoup (author)  pdub775 years ago
conrad24685 years ago
needs to be a little more viscus....blood wouldnt run out that fast.....but other than the viscosity problem.....5 * instructable!!!!!
tastysoup (author)  conrad24685 years ago
Thanks for the post. Yes, the viscosity is definitely an issue but it is something that you can play with. For our purposes we are going for a 70s low budget horror look so I decided on the straight water and color. If you do go with a more viscose blood, you need to work on the speed with which it soaks through the shirt. Although real blood is viscous, it soaks through material immediately. When I tried using corn syrup or even water/corn syrup mix, it took a split second to soak through. One solution might be to use less blood in the condom but for our movie, we are kind of going for ridiculous. Let me know it you can think of something that might have the viscosity of blood with the same soak speed.
Wonderful... Now I need to come up with an idea of what to use it for.
marc925 years ago
So this effect is set off by a firecracker pressed against the actor's chest? Seems a little dangerous to me.
tastysoup (author)  marc925 years ago
The cardboard is against the skin, The firecracker is separated from the skin by the cardboard and the condom full of blood. I have done this many dozens of times and you do not feel anything. Almost all of the force is directed away from you which is why it blows a hole through the shirt. I think that the liquid itself creates enough pressure to reflect the blast. As a testament to this, when I have used a rubber glove instead of a condom, the blast wouldn’t always burst the blood pack. Of course I wouldn’t use anything bigger than a black cat type firecracker. An M80 or something like that would probably be a bad idea and as with all explosives projects, great care must be taken as every step but a black cat is about the same thing as a professional squib.
Oh, I see. I thought that the side of the pack you can see in the thumbnail image was the side that goes against your body.
tastysoup (author)  marc925 years ago
Sorry, I probably should have specified that. Yeah, if you put it on backward, it would probably be like getting shot, point blank with like a .22. I will update the instructions.
Nah. A black cat going off on your skin feels like getting hit with a paintball at about 300-400fps, point blank. It WILL leave a welt.
tastysoup (author)  Pazzerz5 years ago
That is true if there is nothing behind the firecracker but if it is pressed against your skin by the blood pack and cardboard duck taped there, the blast will be forcing a lot more pressure into the skin. It probably wouldn't be as powerful as a gunshot but shaped charge kind of things are weird and I wouldn’t be surprised if it was a lot more powerful than it would seem. But the main point is, don't do it.
I agree, don't do it. But even with what you talked about, I've already seen the results: A bruised big welt. (went off between the person's clothing and skin. He-he! He grabbed at it just as it went off and basically pushed it against himself.) Just another example of wondering how we managed to reach adulthood.
tastysoup (author)  Pazzerz5 years ago
Daaaammmnn! Ok, that would be messed up.
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