Pyrotechnics

[exarch]

I figure this is the right place to ask about this. The recent festivities reminded me of this question.

I remember there being a thread over at SC about fire-works, but that question was about coloured fire.

Anyway, I'm looking for a way to make a bang and get some smoke in a replica of a percussion cap pistol I have. I don't intend to propel anything, it just needs to appear like it fired a shot (and the bang doesn't need to be earshattering).
I'd also hope to get that done using the actual moving parts of the replica (it's not actually a working model, just a mantlepiece decoration, but all the parts move and have springs, although they may need some holes drilled or something to carry the spark into the barrel). If at all possible, something that doesn't take too much time to "load" or "set off" either.

Is there anything apart from actual gunpowder that could be used safely? (i.e. not accidentally igniting in your hand or pocket, or the gun blowing up in your face or something) :covereyes
Perhaps even something I could mix up at home without alerting the authorities of possible terrorist activities?

And if at all possible, something relatively inexpensive.

Any pointers would be appreciated, although I'm basically asking you to teach me how to make explosives :D

[wunky]

After you get it figured out- will you be willing to share your creation.
Never know when it will come in handy.....

[kevin]

you're looking for something called flash powder. Don't remember exactly how to make it, but dig around on the internet a bit you'll figure it out.

and remember a couple of things:
* these days cops are absolutely paranoid about explosives stuff. don't get arrested

* don't blow your hands off. A good dose of paranoia about what your handling is always good. small batches!

and i probably wouldn't put this in a gun shaped thing without lots and lots of testing. That's pretty close to building a pipe bomb.

[exarch]

After you get it figured out- will you be willing to share your creation.
Never know when it will come in handy.....
Sure enough. I've already made pictures of the inner workings of the gun and plan to make a step by step report. Because you never know ...

The screws on the pistol aren't real, the cover plate just sort of snaps on ...
http://users.pandora.be/exarch/LARP/Pistol/Full%20view.jpg

Inside, it looks like this...
http://users.pandora.be/exarch/LARP/Pistol/Cover%20plate%20removed.jpg

I find the inner workings of this gun to be surprisingly simple. Much like the real deal would probably be.
Although some research into the workings of a flintlock shows that those weren't very complicated guns anyway.

And a detail of the breach with the breach cover thingie removed. I even added a dime so you 'mericans would have a size reference ...
http://users.pandora.be/exarch/LARP/Pistol/Breach%20guard%20removed%20-%20detail.jpg

It is unfortunate that the trigger doesn't lock when the gun is half cocked though. And the aforementioned "breach cover thingie" is (at the moment) one solid piece.
I think the entire thing is made of zamac(sp?) or something. A cheap and light aluminium alloy that doesn't corrode like iron or steel does and can be worked at lower temperatures.

[exarch]

and i probably wouldn't put this in a gun shaped thing without lots and lots of testing. That's pretty close to building a pipe bomb.
Of course. Especially since this is only a replica and probably not as sturdy as a real gun.

[kevin]

I'm thinking a really light load of black powder (not modern gun powder) is what you're looking for.

flash powder is more explosive (black powder actually burns pretty slowly compartively) and burns hotter.

but i'm not convinced black powder won't melt the metal pieces. Pretty sure flash powder will melt it repeated firings.

[Bikewer]

The problem with getting this replica to fire anything will be the lack of a proper breech-firing pin, etc.
This is a replica of a Remington rolling-block pistol, wherin the falling hammer is part of the locking mechanism for the breech. From the photos, it does not appear that there is any sort of actual firing mechanism. You would have to construct a cartridge of some sort; as I doubt the "breech" conforms to any standard cartridge. ( indeed, it doesn't appear as if there is any sort of "chamber" at all, as the rifling in the bore goes all the way back to the breech-face.

Be aware also that flash powder is quite volatile, and any resistance at all can cause very high breech pressures. Something this pot-metal replica would not stand!
I would reccomend against the project.

[HighRiser]

From what I can see in your photos it looks like the simplest solution would be to adapt the breech block to accept a percussion cap nipple and modify the hammer to be able to fire the cap.

Standard precussion caps are small brass cups that contain a small load of fulminate of mercury which will explode when struck by a hammer. The advantage here is that you do not have to determine the size of the gunpowder load to use, because over-estimation of a load of gunpowder could be hazardous to your health. I recommend not fooling around with gunpowder at all if you have had no formal training in the handling of explosives. Just opening and closing the lid of a can of black powder could possibly cost you life or limb.

Gun shops that sell muzzle-loading equipment will have percussion cap nipples that are basically a small pipe fitting with male pipe threads on one end, hollow through, and the correct size and shape tapered tube to accept a standard percussion cap on the other. This will involve drilling and tapping threads into the breech block after getting the geometry figured out. The geometry will be the trickiest part.

[Dan Beaird]

Your replica pistol appears to be made of cast parts probably made with whatever metal was in the pot when the time came to make it. In Colonial times they would have called it pewter. As a cast piece no attempt has been made to heat treat or strengthen the parts, even a tiny percussion cap could cause the metal parts to shatter. Do not, under any circumstances whatsoever, put anything explosive in the gun.

It looks like it's supposed to be a rolling block breach loading single-shot pistol. Remington made some I believe for the British Cavalry before they adopted revolvers back in the late 1860's or so.

Real black powder pistols aren't that expensive, you can get good ones for $200 or so. I've got a few charcoal burners myself and love to shoot them, but this one you've got needs to hang on the wall and stay there.

[Soapy Sam]

I tend to agree with Dan, however...as kids we used to open "bangers"- the simple firework that goes "bang", then we took about 1/4 of the powder and pushed it into a toy gun (revolver) and held it in place with a paper wad.
The gun itself "fired" the sort of tiny caps that came on long paper strips. (In those days they cost a penny a packet of 100.)
The ignition of the cap was usually enough to ignite the powder, which , being unconstrained, simply blew a big cloud of smoke out of the barrel.
Inevitably, we experimented with projectiles- I had some wooden bullets which fitted pretty tightly.
Result, a blowback and scorched thumb. No biggie, but I could have been siting along the barrel and lost an eye or three.
Be careful. Carry out any experiments at arms length, outside and with a face shield.

[kevin]

Be careful. Carry out any experiments at arms length, outside and with a face shield.

i'd have to go with the string around the corner of a nice thick wall method myself. I like my fingers.

[HeyLeroy]

i'd have to go with the string around the corner of a nice thick wall method myself. I like my fingers.

What he said. Repeatedly. replicas are usually made of zinc. Soft enuf, for a metal, but harder by far than your fleshy parts. ANY obstruction in the barrel and...

A better bet would be to try and find a blank-firing replica, they're engineered for this sort of thing.

[exarch]

The problem with getting this replica to fire anything will be the lack of a proper breech-firing pin, etc.
This is a replica of a Remington rolling-block pistol, wherin the falling hammer is part of the locking mechanism for the breech. From the photos, it does not appear that there is any sort of actual firing mechanism. You would have to construct a cartridge of some sort; as I doubt the "breech" conforms to any standard cartridge. ( indeed, it doesn't appear as if there is any sort of "chamber" at all, as the rifling in the bore goes all the way back to the breech-face.
Actually, I don't even think that's rifling, I suspect it's merely flash or something. The front of the barrel actually has a much cleaner finish, and it's smooth inside.
So from what I can tell, it's actually a replica of a cartridge firing pistol then. Although that makes me wonder why the bore is so large.

Anyway, at least I now know which gun it's probably supposed to resemble (or at least based on, i.e. the Remington 1891 Rolling Block Pistol (http://www.armchairgunshow.com/images/CR-52-dd.jpg)).

Be aware also that flash powder is quite volatile, and any resistance at all can cause very high breech pressures. Something this pot-metal replica would not stand!
I would reccomend against the project.
I definitely wasn't planning on any powder charges resembling reality in size. Just enough to get a bit of a bang and some smoke.

And yes, testing from 10 feet away with a piece of string attached to the trigger was my first thought as well ...