Cannons, fireworks, experiments, projects

[patrickg]

Old_Wanker, You might like rocketry on a small scale, relatively safe small scale. Take a paper match and lay a straight pin along the match stick with the point of the pin toward the match head and touching the match head a bit.

Wrap the match head and maybe 3/16 of an inch of the stick with aluminum foil. Press down around the pin to get a good impression then remove the pin. This has formed the exhaust nozzle. Prop the rocket up on a mangled paper clip. Lean the rocket over about 45 degrees. Light a second match and hold the flame under the head of the wrapped match. When the rocket's propellant (match head) cooks off (ignites) the rocket may go 0-15 feet depending on skill and luck.

To "hot rod" the design. Carefully trim away much of the width of the paper match stem (stick?), especially the part farthest from the head. Since the equation F=MA (force equals mass times aceleration) or for our use, solving for A (acceleration) we have A equals force divided by mass. Force is determined by propellant and nozzle and we are somewhat limited as we buy off the shelf rocket motors (paper matches) and the nozzle is "good enough" but can be subject to experiment however, the mass of the rocket's aerodynamic stabalizing fin (stem/stick) can be reduced by narrowing it. I don't recommend shortening it as aerodynamic instability ensues. You can hot rod the rocket motor a bit by including a bit of extra fuel say 1/4 of another match head (without any paper stem material of course. You can try to minimize the quantity of aluminum foil used but too little and the sidewall of the motor will blow out.

Caution, aluminum heated by a burning match can burn you. If a rocket lands on bare skin it can smart a bit or startle a napping tabby. Never started a fire this way but suppose it is possible so use caution around open pits of gasoline (petrol), caches of high explosives, and like that.

Dimensioned cad drawings available at modest cost.

Enjoy,

Patrick

 

[bgott]

I have always found acetylene bombs wired to brakelight circuits amusing, as long as I knew they were there. You can also build an impressive bomb just by pressurizing a sealed anti-freeze jug with 150 p.s.i. shop air. A car battery charged at a high rate is an effective hydrogen generator. I blew one battery up in my face, I remembered the warning signs, on the others I've had blow I've managed to turn and run. FYI, if you have a shorted battery and try to charge it, you'll hear a few little pops out of the battery just before it grenades. The first little pop will send me about two bays over before the second hits. To use the battery as a hydrogen generator we'd drill holes in the top of the caps and stretch balloons over them. Fuse the balloons and let them drift past second story apartment windows at night, coitus interruptus guaranteed!

 

[patrickg]

bgott, Outa sight duuuuuuuuuude.

Been lucky, only blown the filler caps off of a 100 amp hour 12 volt battery one time and no other similar action. Seems I was testing a prototypebattery operated arc welder on a consulting job to a startup company trying to get into the market with this man-portable battery operated arc welder (23 lbs less battery which in normal operation stayed in the vehicle). I was using it in stick welding mode, burning rod after rod with a 100 amp-hour truck battery as the power source. So this spark from my welding hits the hydrogen gas streaming out of the battery's vented caps and pop goes the caps. Kind of a whistle sound as the products of combustion rush out through the vent hole just before the caps are fired up into the air striking the ceiling of an open bay industrial rental with 20 ft ceilings. Banggety bang bang bang as they impact the metal roof then tink thunk tink tink thunk etc as they fall to the floor. Everyone looks at me as if I should be paying them to play there rather than them pay me to save their sorry little outfit from bankruptcy.

Been bunches of more careful since then.

Patrick

 

[Old_Wanker]

patrickg I like that device. I can see myself playing with that when Im at some of the usual summer picnics with the wifes family.

Heres a tip for a handy ignition device for fireworks. Take a flashlight bulb and with a dremel carefully cut off the glass. Crumble some of the heads of some matches into a fine powder. Spray glue on the filament and filament supports of the bulb and sprinkle the phosphor on. Repeat a few times. Now apply a voltage to the bulb.

 

[TWINKLE_TOES]

Old_Wanker,

Flash bulbs work very well. The glass is laced with plastic and easy to drill and stay intack.
Al

 

[Old_Wanker]

I tell you - put a radio control unit on one of these with the innards from a nice big firework and you can have lots of fun.

 

[TWINKLE_TOES]

Old_Wanker,

How did you get the handle "Old....." thinking that way /w3tcompact/icons/wink.gif Might work great until the first trucker rolling thru with a 1000 watt linear. Yikes
Al

 

[patrickg]

Old_Wanker Yeah, neat DIY igniter. Saw something like that in a prison movie with, I think, Sean Penn. Small hole in the base of a light bulb and fill partially with gasoline (petrol). Put in overhead light fixture and wait for victim to turn on the light.

Estes engineering sells rocket kits, motors, A N D igniters. piece of resistance wire with a plastic coating. When wired up and energized with a battery it gets hot and lights their rocket fuel. Shouldn't be as hard to duplicate skill and tools wise as your igniter but if you have the stuff for yours and not theirs it would still get the job done. I have set off a lot of remote pyrotecnics by clipping a couple small alligator clips to the fuse or sticking pins in it. Connect up 120VAC (less would probably be fine, but never tested lower limits) and we have I G N I T I O N. Needles driven into a cherry bomb or M-80 type firecracker itself, not the fuse gives virtually instant response should delay be a problem.

Try the match rocket. We used to have contests at lunch time trying for greatest range or accuracy (waste of time,not accurate) when there weren't any engineering majors for us physics majors to pick on or have match rocket duels with.

You could use match rockets to celebrate... D A R E I S A Y I T, the 4th of July. I gotta go...

Patrick

 

[DocHeb]

For your consideration. Sorry, a bit difficult to read.

 

[bgott]

I was about thirteen and working in a junkyard when I blew the battery up in my face. We had an old wrecker there that needed jumped because we never had a good battery in it. I was jacking with the cables when one of the posts broke loose in the battery. Pop, pop, pop, POW! The other ones I've blown just started popping with the charger on high. I guess they had a connection melt from the heat and short out.

 

[bgott]

We used L194 bulbs and dash light sockets for the brake bombs. Crush the bulb and make sure you don't break the filament.

 

[BWa]

My father-in-law as a kid was very much in to chemistry and had a few tales that he would relate to now and then , one was his part time business of Rock and Stump Removal ..... that was going great until one day he was tamping a rock full of home made and had it go off , ....... he was using a steel axial as a tamp ...... he said it went up out of site and was up a longgg longgg time before he heard a whisle like sound and a splash out in the near by pond ....
He was also asked to help a couple of the local crooks , cook out a little nitro from an old case of tnt ...... he truned that down and for a long time these two crooks had a good busines suppling the other locals with this liquard box opener .... until they got some a bit to warm and had it go up and with it there business, the police for some reason was not very unhappy at this turn of events .

He got over this intrest in that which goes bang and turned to working with glass .... If you got the time try a search for Charles Kazuin Glass Work .
Bill G.

 

[Old_Wanker]

TWINKLE_TOES,

Thats a fair point. Maybe I should change my handle to Lucky_Old_Wanker. Where I grew up in blighty I suppose the truckers didnt have access to that kind of toy for their CBs.

 

[Old_Wanker]

patrickg,

<font color=blue>You could use match rockets to celebrate... D A R E I S A Y I T, the 4th of July. I gotta go...</font color=blue>

Alrighty then indeed - lighting the virtual fuse and then running away from the message board. Theres an old joke that the British eat Turkey on July 4th (their thanksgiving) and have fireworks in November (their independence).

However having lived here for many years now I really dont get rattled. After all Ive chosen to make my life over here and not back there. That has to say something about which country I prefer the way of life in. At risk of serious digression I have to confess to being a republican (as in not a royalist) and am therefore a true American at heart even though there seem to be more royalists in America than ever these days.

To keep things threadworthy have you ever tried to make lead azide? Now theres an interesting compound. Used to be the primary in most detonators. I made some at college with a friend that was doing Chemistry and we almost deafened and blinded ourself when it cooked off on the stove in our dorms. A bit like having a stun grenade dropped right in your lap. Lots of laughs now but quite dangerous.

 

[Old_Wanker]

Good thing they dont have those city ordnances out where I live. I do understand why they have them though and I would never want kids around one of those devices. One barbecue I was at had a mishap when the spud gun (run off hairspray and using a grill igniter) developed a big crack down the side. Im surprised that the fellow that had it on his shoulder didnt soil himself. I prefer remotely operated devices myself.

 

[patrickg]

Chris, Thanks for the clipping. There is evil and there is the appearance of evil and then worse yet there is well intentioned but innappropriate censorship. I don't have a problem with dangerous devices being confiscated in public areas or fines and jail with proper advance notification BUT... I sure wouldn't want to see it illegal to build and operate a "potato gun" on private property or even to interfere with a private owner having a "meet" and inviting competitors to a "range" and or "accuracy" shoot.

Ever see the old poster of the OSHA approved cowboy? Roll bars, seatbelts, automatic pooper scooper behind horse and on and on, a true Rube Goldberg delight. Of course it would be impossible to cowboy with that equipment but non-productivity aside, you would be safe thanks to big brother.

As a 9th grader in OK I could buy cherry bombs, M-80's, torpoedos, etc. across the counter at the Ben Franklin 5 and dime store. I don't recall anyone evrer throwing dangerous fireworks into a crowd. California on the other hand, university area... university students had an annual Haloween riot. The police try to disperse crowds but there is no way to handle the numbers without severe injury. Cherry bombs and stuff is thrown into the crowds by other students, it was not sane. I watched, because I was there, but did not participate except once sort of. One evening (day before haloween) some of the wild bunch came into the court yard where my German language class was meeting at the instructor's lodgings and wanted to throw the manager in the pool because he asked them to stay out. Another ex-GI and I stood up to the crowd and when the ringleader got in our face trying to show off for his followers we threw HIM in the pool and offerd to accomodate the next few in line so they dispersed. We then helped the BIG MAN out of the pool and enquired if there was any further buisness he might like to conduct manually with either of us. HE just left.

There is a fine line between personal liberty/freedom and appropriate societal control. Where you think the line belongs says worlds about character, personal responsibility and so forth, not to mention politics.

Gotta go,

Thanks again for clipping.

Patrick

 

[patrickg]

Old_Wanker, I really like the turkey in July and fireworks in November. Clever without hitting you over the head with a sledge. I tend to like British humor,most of the Britcoms I've seen. Monty Python was a hoot most of the time. Benny Hill was a bit over the top some of the time but I miss the bugger. While not a through and through angliophile (sp?) I did enjoy my 3 weeks in England... mostly London, mostly working, and mostly indoors at Whitehall but got around a bit. Saw Greenwich, was at ground zero on rememberance day chatting up the piper, a member of the London Scots. Had a great lunch at British Aerospace, very upercrust and formal serving and marvelous food (no matter what folks say about English food) Oh well, one day the'll discover vegetables. Loved shopping Portobello (sp?) Road, nearly fainted at prices in Harrod's.

I noticed some stuff at the feed store that you light and put down a gopher hole. Picked it up and read the ingredients. Same stuff I whipped up on my own in 9th grade. Mostly salt peter and sulphur. Gasses the lil devils.

Thinking of making a batch and trying it on armadillos.


Patrick

 

[bgott]

I have a friend that makes contact explosive out of iodine and I don't know what else. This stuff is stable in liquid form but once it dries just a step will touch it off. He used to like to go to the store and drop the stuff around with an eye dropper. It isn't violent enough to hurt anyone, I've stepped in it myself and didn't even feel it. It does, however, make a sharp enough crack to have someone dancing around wondering just what the hell is going on!

 

[DocHeb]

We used to make the Iodine Trinitrate contact explosive in chem lab as an undergrad. We used Iodine crystals and anhydrous ammonia. No problems when wet, but watch out when it dries.

See:<A target="_blank" HREF=http://www.totse.com/en/bad_ideas/ka_****ing_boom/contact.html>Contact Explosives</A>

 

[Henry]

Ahhh, have you guys discovered Spud Guns ? My son made one a while back. It's basically a 6 foot section of PVC pipe, stuffed with a potato, It has an ignition chamber that you fill with cheap hair-spray and ignite with a peizo-electric grill starter.

It will fling a potato a good 200 yards !!!!

Take a look at

<A target="_blank" HREF=http://www.aaroncake.net/spuds/>http://www.aaroncake.net/spuds/</A>