Register to reply

Igniting gunpowder?

by Il Buono
Tags: gunpowder, igniting
Share this thread:
Il Buono
#1
Aug3-09, 04:10 PM
P: 3
I'm not really sure this is the right sub-forum for my question but here it goes:
I've had some trouble igniting a smal quantity of gunpowder using a 9V PP3 battery. What I want is to make a movie special effect for a bullet ricochet and I think it will look good with a little gunpowder igniting. So I put two wires conected to the terminals of the 9V battery in a smal pile of gunpowder hoping to make it ignite but nothing happend. I was counting it would iginte due to a sparking between the two wires or the generated heat of the electrical current. I saw a simillar method in a Mythbusters episode (they put some gunpowder with wires in a jawbreaker and connected the wires on a 9V battery - but I didn't see it clearly so were they using something else? Also in another MB episode, they ignited gunpowder by placing it between two nails wich were connected to a battery - again I didn't quite understand the concept how it worked). So how do I ignite gunpowder using a battery?

*Note that this is not homework and I apologise if I posted the question on the wrong sub-forum

Cheers
Phys.Org News Partner Physics news on Phys.org
Step lightly: All-optical transistor triggered by single photon promises advances in quantum applications
The unifying framework of symmetry reveals properties of a broad range of physical systems
What time is it in the universe?
negitron
#2
Aug3-09, 04:20 PM
Sci Advisor
negitron's Avatar
P: 842
Yes, they used what's called an "electric match." Go into any hobby shop that sells model rocketry supplies and ask for some. I'm not sure of the cost, but it's not all that much. An e-match is basically a small piece of thin resistance wire coated with a flammable substance; you put a current through it, the wire heats up and ignites the coating which, in turn, ignites your gunpowder.

Please be VERY careful using gunpowder. Before you fire your shot be ABSOLUTELY sure that all the unused powder is safely far away and in a closed container. And use the absolute minimum your effect requires. Safety first!
turin
#3
Aug4-09, 01:22 AM
HW Helper
turin's Avatar
P: 2,327
Did you consider using flash powder? I don't suppose that will solve your ignition problem, but it may give you a better visual effect.

Danger
#4
Aug4-09, 05:19 AM
PF Gold
Danger's Avatar
P: 8,964
Igniting gunpowder?

Two things here...
First, bullet strikes, even on metal targets do not spark. That's Hollywood ********. There's a tiny possibility that a steel jacketed bullet might produce an almost unobservable spark hitting steel, but the crap that you see in movies is just laughable.
Secondly, if you want a (semi) realistic bullet strike in something like concrete or wood, you place your squib in the appropriate place and just let it blow a hole in the substance without any noticeable light.
Thirdly (okay, so I can't count), if you insist upon making it look stupid, I'd use black powder or, as Turin suggested, some flash powder. That's essentially a weak form of black powder. Bear in mind that black powder is a high, rather than low, explosive, and has to be handled with extreme caution.
The e-match that Negitron mentioned, which is known in my area as a 'solar ignitor' is the best way to light off your effect. It's what you stick up the *** of a model rocket engine to launch the thing.
I design and build special effects and prosthetic makeup (as a hobby, but hope to get into it professionally). Nothing is as easy or as hard as it seems from the outside. I can use stuff lying around my house to make a guy's head explode on camera or even on a live stage, while the original Yoda (muppet as opposed to the later CGI version) in 'Star Wars' cost thousands of dollars and took several puppeteers to operate. Unless it's a high-end professional movie that you're making (in which case you wouldn't be here asking advice), stick to the cheapest way to do things. Just choose your materials carefully and plan well in advance. Blood and guts for an exploding head or a severed limb, for instance, is easily accomplished with a mixture of soggy bread crumbs, gelatin, and red food dye.
Back to the sparking ricochets, though... you could also simulate them with electrically triggered flashbulbs or high-intensity LED's.
Ranger Mike
#5
Aug4-09, 05:27 AM
Sci Advisor
PF Gold
P: 1,473
ditto for what DANGER said...listen to him and save a limb...btw i hate muppets..glad to here you making them dust and like to see the video, Danger!
ideasrule
#6
Aug4-09, 05:28 AM
HW Helper
ideasrule's Avatar
P: 2,322
Quote Quote by Danger View Post
Thirdly (okay, so I can't count), if you insist upon making it look stupid, I'd use black powder or, as Turin suggested, some flash powder. That's essentially a weak form of black powder. Bear in mind that black powder is a high, rather than low, explosive, and has to be handled with extreme caution.
Black powder is a low explosive. A high explosive would be something like ammonium nitrate--totally unusable as a firearms propellant.
Danger
#7
Aug4-09, 06:05 AM
PF Gold
Danger's Avatar
P: 8,964
Black powder is considered a high explosive in that it doesn't have to be confined in order to explode. I'm not talking about detonation rate. If you hit modern smokeless powder with a hammer, nothing happens. Try that with black powder and you'll be pulling steel fragments out of your body for a week.
negitron
#8
Aug4-09, 07:36 AM
Sci Advisor
negitron's Avatar
P: 842
Quote Quote by Danger View Post
Bear in mind that black powder is a high, rather than low, explosive....
No, it is not*. However, that doesn't mitigate the caution to handle it carefully!







*Black powder in ordinary amounts is a low explosive, however, very large quantities can, in fact, detonate as a high explosive.
Ranger Mike
#9
Aug4-09, 07:41 AM
Sci Advisor
PF Gold
P: 1,473
frum wikopedia...subsonic versus super sonic...bottom line is...Don't mess with it!!

Gunpowder, also called black powder, is a mixture of sulfur, charcoal, and potassium nitrate. It burns rapidly, producing volumes of hot solids and gases which can be used as a propellant in firearms and as a pyrotechnic composition in fireworks. The term gunpowder also refers broadly to any propellant powder. Modern firearms do not use the traditional gunpowder (black powder) described in this article, but instead use smokeless powder. Antique firearms or replicas of antique firearms are often used with black powder substitute.

Gunpowder is classified as a low explosive because of its relatively slow decomposition rate and consequently low brisance. Low explosives deflagrate at subsonic speeds. High explosives detonate, producing a supersonic wave. The gases produced by burning gunpowder generate enough pressure to propel a bullet, but not enough to destroy a gun barrel. This makes gunpowder less suitable for shattering rock or fortifications, where high explosives such as TNT are preferred.
Danger
#10
Aug4-09, 01:44 PM
PF Gold
Danger's Avatar
P: 8,964
Okay, I stand corrected on the high/low explosives definition, but the stuff will still explode under impact as opposed to having to be packed into an enclosure as is needed for smokeless powder or gasoline. A buddy of mine lost most of his eyebrows, and nearly his vision, poking some with a stick when we were kids.
Il Buono
#11
Aug4-09, 03:05 PM
P: 3
Big thanks to Negitron, Turin and Danger!
I'm not quite sure that there is a single store in my country (Croatia) that sells anything simillar to e-matches.. xD.. so I'll try making some from scratch (salvaging light bulbs).
Oh and Danger, I know it's offtopic but I would really like to hear more about special effects :) so do I contact you trough PM or..?
Thanks again guys!

Cheers
negitron
#12
Aug4-09, 04:22 PM
Sci Advisor
negitron's Avatar
P: 842
You can probably make them cheaper with steel wool. Pull out a loose strand about an inch long and wrap each end around a heavier copper wire (one wire per end; you may have to bend the copper in a tight "U" shape to hold it in place), then connect your copper wires across a 9 V battery. It will glow yellow to white hot for an instant before burning out.

Yes, I was a bad kid.
Danger
#13
Aug4-09, 09:22 PM
PF Gold
Danger's Avatar
P: 8,964
Quote Quote by Il Buono View Post
Oh and Danger, I know it's offtopic but I would really like to hear more about special effects :) so do I contact you trough PM or..?
Thanks again guys!

Cheers
Your more than welcome. Unfortunately, I can't be reached by PM because my mailbox is full and I'm still trying to save the previous messages to my HD with little success. Until I can do so, I can't delete the current overload. Every PM that I receive is important to me, so I don't want to risk losing one.
What seems to work, as some have done it, is to use the PF e-mail function, which redirects to my real e-mail account without giving away my address. No offense, but I prefer to keep that private until I get to know you better.
I'm certainly more than happy to discuss any FX or make-up stuff with you, but keep in mind that I am strictly an amateur. If you want a couple of rather poor examples of my work, check out the alphabetical listing of PF Member photos. There's a full-frame version of my avatar, which is me in my Hallowe'en make-up from about 6 years ago. The one entitled "Danger's bartender" is a job that I did on the barman at my favourite watering hole. That took a few hours to build and 10 minutes to apply.
Danger
#14
Aug4-09, 09:44 PM
PF Gold
Danger's Avatar
P: 8,964
Actually, since you're new here this might require some explanation. Go down about 6 threads in General Discussion to one called Member Photos—alphabetical. Click on it, and scroll down through all of the names, past the Z's. There's a second category after that called something like Jokes / Deleted / Miscellaneous (I can't remember exactly). When you click on Danger, it will take you to a page that references my pictures, but you then have to back up one or two pages to see the actual pictures. The first one is my bartender, and a couple of posts below that is me.
Il Buono
#15
Aug5-09, 03:04 PM
P: 3
Negitron, big thanks on the home-made e-matches 101 !
Danger, I saw the photos and I can say that the makeup job is actually quite good. Hey, I'm an amateur too but you clearly have way more experience in FX than I do. Looking forward to discussing FX with ya!

Cheers


Register to reply

Related Discussions
Possibility of igniting Jupiter Astronomy & Astrophysics 32
1000 years to improve on gunpowder General Engineering 9