Sciencemadness Discussion Board - high sensitivity low explosives

high sensitivity low explosives

John paul III - 22-10-2019 at 13:37

I am experimenting with homemade gunpowder cannons (small scale). I use a piece of twisted paper soaked in saturated KNO3 solution and dried to set off the powder through a touchhole, lit with a lighter. I want to add a striker system, but I don't really want to handle and store primary HE's. Are there OTC friendly low explosives that could be set off by impact?

[Edited on 22-10-2019 by John paul III]

[Edited on 22-10-2019 by John paul III]

Alkoholvergiftung - 22-10-2019 at 13:44

The first Primary was an mix of Sulfur Potassiumchlorate and characol. They used it in the pull ignigors for guns too.

wg48temp9 - 22-10-2019 at 14:18

You could use the red mixture from the match heads of Swan strike anywhere matches.

When you wrap the mixture in foil and hit it with a hammer on a hard surface it makes and load bang.

Twospoons - 22-10-2019 at 16:42

Why not use a flintlock mechanism?

Sulaiman - 22-10-2019 at 20:47

You are effectively making a firearm ... consider the legal implications.

I used to play with cannons in my youth ...
remote ignition or a light-and-run-away fuse is safer.

Vomaturge - 22-10-2019 at 21:33

How about some toy caps off the shelf and very loud/bright. Just keep in mind the legality as sulaiman pointed out, and also that these things are pretty sensitive-you might get some accidental initiations while pushing them into place. That or go electric.

Praxichys - 23-10-2019 at 04:14

Quote: Originally posted by Sulaiman

You are effectively making a firearm ... consider the legal implications.

Indeed. Where I live, "The term “Firearm” means: Any weapon (including a starter gun) which will or is designed to or may readily be converted to expel a projectile by the action of an explosive" (ATF website, USA)

While I doubt police anywhere would prosecute this to the fullest extent unless someone was hurt/property was damaged, it is worth knowing that manufacturing and discharging a firearm might have severe legal consequences in your area.

Here in the USA it is perfectly legal to make your own and use them on your property as long as you're not in a state/township/city that specifically prohibits this, which is basically everywhere except the East or West coast.

unionised - 23-10-2019 at 09:59

Quote: Originally posted by Alkoholvergiftung

The first Primary was an mix of Sulfur Potassiumchlorate and characol. They used it in the pull ignigors for guns too.

And there are good reasons why it is no longer used.

Alkoholvergiftung - 23-10-2019 at 10:10

It was saver than mercuryfulminate and glasspowder. What i read they mixed it wet and than they filled the paste in the Primary caps and sealt it with turpentine or linseed oil. Dosent Sound to dangerous for me.

Pyro_cat - 23-10-2019 at 20:23

Go check out the cannons and supplies at dixiegunworks.com nice ones for about $1000 and the big 250 and 300lb ones are about 2000 with shipping.

All kinds of parts and plans and stuff too.

Pyro_cat - 23-10-2019 at 20:28

I recently blew off some plastic caps from the dollar store and they had the exact same smell as the ones from 40 years ago. Strange how memory never ever forgets a smell.

And watch out with homemade cannons. Made one from a log splitter by simply drilling a fuse hole in the steel tube handle by the base. It tolerated dozens of shots with first one then 2 film canisters full of pyrodex with Al foil as wadding. Its last shot it ruptured 1/3 of the way up. They say metal fatigue is a weakening of metal due to stress, resulting in an accumulation of small cracks. I guess that's what happened.

I say always have something solid between people and things that go boom. We were intentionally pushing it and had it behind a tree stump with a big log on top.

[Edited on 24-10-2019 by Pyro_cat]

markx - 23-10-2019 at 23:39

Quote: Originally posted by John paul III

I am experimenting with homemade gunpowder cannons (small scale). I use a piece of twisted paper soaked in saturated KNO3 solution and dried to set off the powder through a touchhole, lit with a lighter. I want to add a striker system, but I don't really want to handle and store primary HE's. Are there OTC friendly low explosives that could be set off by impact?

[Edited on 22-10-2019 by John paul III]

[Edited on 22-10-2019 by John paul III]

The mixture from safety match heads is probably your best bet regarding OTC materials that would suit the purpose. A custom mix of KClO3 C S also works very well, but keep in mind the sensitivity. I would suggest to purify the sulfur by recristallisation from xylene or toluene to remove the residual acidic content. It does stabilise the mix against degradation due to acidic breakdown of chlorate, but it still remains very sensitive towards friction and impact. You need very small amounts of the mix for a striker system, so do not go about mixing a jar full of it and storing on your shelf.
Long time ago I played around with striker systems for flare launchers and operated them with the chlorate mix. Worked flawless and reliably when handled carefully. But it sure does work wonders provoking corrosion on equipment. The residue from the ignited mix is acidic and chloride bearing, so be prepared for heavy rusting of the striker setup...or use stainless parts. I also noted that when a small amount of aluminium powder was present in the chlorate mix, it became inert in the striker setup. No reasonable amount of strike force would cause it to ignite.

wg48temp9 - 24-10-2019 at 00:47

Quote: Originally posted by markx

The mixture from safety match heads is probably your best bet regarding OTC materials that would suit the purpose.

The mixture from the heads if safety matches in my experience do not ignite when compressed with a hammer blow.

Strike anywhere matches (Swan brand with a sand paper striking surface) are more sensitive.

Pyro_cat - 24-10-2019 at 06:21

I just took the flint from a lighter put it on the flat part of the vice and it sparked pretty well with a hammer hit. Never used one of those fire starter flints in the camping section of stores but maybe that could be engineered into an ignition system. Or that flint sparker thing for lighting torches.

Pyro_cat - 24-10-2019 at 06:30

Off topic but its on my pyro bucket list, never got a fire going rubbing two sticks together, my one real attempt I got smoke after the dry wood glazed from the friction and it started squeaking. I did just break my lighter.

Metacelsus - 24-10-2019 at 06:48

Quote: Originally posted by Pyro_cat

Off topic but its on my pyro bucket list, never got a fire going rubbing two sticks together, my one real attempt I got smoke after the dry wood glazed from the friction and it started squeaking. I did just break my lighter.

I've had success with a bow drill (and very dry cedar wood) but never just by rubbing 2 sticks.

Commercial primers

Katie - 26-4-2020 at 22:31

You can buy commercial primers for ammunition. Google “reloading supplies”. I recommend you get the large rifle magnum size (or maybe shotgun primers would be more powerful?) They are relatively cheap, safe, legal, and literally built to be fired by a firing pin.

They also make primers for black powder firearms, which might work best and are a lot larger.