Other type of ignition

Boom! The classic potato gun harnesses the combustion of flammable vapor. Show us your combustion spud gun and discuss fuels, ratios, safety, ignition systems, tools, and more.
Spudgun on Crack
Private 4
Private 4
Posts: 79
Joined: Sat Jun 23, 2007 4:43 pm

Mon Jun 25, 2007 9:04 pm

Ok i forgot to post this so hear it is, if you have a disposable camera of many of them thats good.

Now take them and open one up and keep it in tact, open more if you have them and detach the capacitor, now solder the extra capacitors in parallel with the first capacitor from the first circuit. now you could just use one capacitor but six will give one big spark. You can now charge the capacitor's using the first circuit and then solder two wires off the terminals of the last capacitor. You are now done with this step.

Go to the store and pick up estes model rocket engine igniter's walmart sells them with the motors in the pack but all we want is the igniter. Now take some form of very fast drying glue that is thick not watery and swab the tip of the igniter in it there is now a protective coat over the igniter from the moisture that your fuel may have in it.

To test this charge the camera circuit up and have a 10ft cable to the igniter because this does make a BIG spark trust me. When you touch the leads of the igniter to the capacitor the super thin piece of nichrome wire in the igniter will be vaporized and the crap on the igniter will also ignite making one hell of a spark.

This can also be done with very thin wire.
User avatar
hi
Staff Sergeant 2
Staff Sergeant 2
Posts: 1619
Joined: Thu Feb 01, 2007 9:28 pm

Mon Jun 25, 2007 9:08 pm

it can also be done with a 9 volt battery by the way, but it probably isnt as big.

would it be possible got get a picture or two?
"physics, gravity, and law enforcement are the only things that prevent me from operating at my full potential" - not sure, but i like the quote

you know you are not an engineer if you have to remind yourself "left loosy righty tighty"
Spudgun on Crack
Private 4
Private 4
Posts: 79
Joined: Sat Jun 23, 2007 4:43 pm

Tue Jun 26, 2007 12:05 am

That would be very hard to do because the intensity of the flash will blind any camera or video camera and it only last for about 1-3 frames so i would have to separate the video frames and you may not see it at all just a flash in a picture.

and i do not have a camera setup like that, i have something with the equivalent of 25 camera capacitors but that like explodes the whole igniter 100 joules of power will just plain kill it. It is four large capacitors and a flyback charger.

But the wire is so tiny more power won't do much more, but my design should be able to be used as a last resort in case a BBQ igniter won't work this spark will expand and be very big inside a potato gun, it will work but if you use the igniter it does leave behind a little bit of smoke but that's not bad for the size of the spark.
User avatar
psycix
Sergeant Major 4
Sergeant Major 4
Posts: 3684
Joined: Mon Jun 25, 2007 7:12 am
Location: The Netherlands

Donating Members

Tue Jun 26, 2007 4:32 am

could you post a scheme?
that would be very very nice :)
User avatar
Hotwired
First Sergeant 3
First Sergeant 3
Posts: 2599
Joined: Fri Oct 13, 2006 5:51 am
Location: UK

Tue Jun 26, 2007 4:55 am

A sledgehammer to crack a walnut?

All it really needs is a tiny spark a mm or so long.

Charging a capacitor bank over a couple of minutes then dumping that though a pyro rocket ignitor seems like too much effort.

I suppose if nothing else is working that will certainly get it going :wink:
jimmy101
Sergeant Major
Sergeant Major
United States of America
Posts: 3197
Joined: Wed Mar 28, 2007 9:48 am
Location: Greenwood, Indiana
Has thanked: 5 times
Been thanked: 15 times
Contact:

Tue Jun 26, 2007 6:33 pm

Why do you need the rocket igniter? A thin piece of wire will vaporize just as nicely (and as hot) at those current and voltage levels.

If you are using an ignitor all you need is a standard 9V battery, why go to all the trouble of the photocaps?
Image
Spudgun on Crack
Private 4
Private 4
Posts: 79
Joined: Sat Jun 23, 2007 4:43 pm

Tue Jun 26, 2007 11:50 pm

Yes any thin piece of wire will work but a rocket igniter is coated with so sort of crap that makes it explode a big but yes you don't need a rocket igniter as a small piece of wire will work.

This is also overkill, the spark would be the size of the chamber itself which is not needed, i was justing stating that this method will work if there is any problems with small sparks igniting it.
Spudgun on Crack
Private 4
Private 4
Posts: 79
Joined: Sat Jun 23, 2007 4:43 pm

Tue Jun 26, 2007 11:54 pm

I will try and finish a simple prototype and get it on tape but it will be a while so hang on. I want to build a camera flash cap box with like 50joules of energy for multi use so i am gona build one anyway but it's a matter of when i get the money as i spent the money i had on tools and crap to build my pneumatic.
User avatar
Flying_Salt
Corporal 3
Corporal 3
Posts: 779
Joined: Mon Oct 09, 2006 4:57 pm
Location: Texas

Tue Jun 26, 2007 11:58 pm

Ouch...run-on sentences hurt my eyes.

That said, what does one do when they have lots of model rocket engines laying around? :twisted:

I guess it could work but it would be a lot of trouble. Maybe next time I'm at a grocery store I'll ask for empty camera casings and have fun with electricity.

That brings up another question, have you ever touched your series of charged capacitators?
hi wrote:would it be possible got get a picture or two?
I think he meant a picture or two of the array of wiring, capacitators, etc.
sgort87 wrote: I hereby present Flying_Salt with The one and only <a href="http://www.geocities.com/sgort87/ghetto">Ghetto Award!</a>
User avatar
boilingleadbath
Staff Sergeant 2
Staff Sergeant 2
Posts: 1635
Joined: Sat Mar 12, 2005 10:35 pm
Location: Pennsylvania, USA

Wed Jun 27, 2007 12:03 pm

You guys do know that systems such as this are used to directly detonate not-so-unstable explosives, right?

Minus the pyrogen on the wire.

Seriously. The explosion of the wire is forceful enough to directly initiate secondaries.

That said, it might not be the safest thing to do, because strong ignition sources make DDT occur quicker.
Spudgun on Crack
Private 4
Private 4
Posts: 79
Joined: Sat Jun 23, 2007 4:43 pm

Wed Jun 27, 2007 7:28 pm

Yes this is a very strong ignition source, i set a model rocket off with this once and it usually takes 1-3 seconds to go off but i swear that as soon as the leads in the switch touched it went sky high. So yea this will ignite something if all other sources fail.

And as for the question "did i ever shock myself" yes with one half charged capacitor and it hurt like hell, i could not feel my hand for about 6 hours.

This topic does not need to go on any longer as i was just saying that this is like a 100% guarantee that your cannon will go off if other ways don't set it off.
User avatar
Redcoat
Corporal 4
Corporal 4
Posts: 835
Joined: Tue Feb 13, 2007 1:07 am
Location: Sydney ,Australia
Contact:

Wed Jun 27, 2007 7:40 pm

Are those Estes model rocket igniter's one shot disposable or do they have an excessive amounts of ignitions in them.

Also are they expensive :?:
Poo.
sandman
Corporal 2
Corporal 2
Posts: 672
Joined: Thu Mar 15, 2007 6:59 pm

Wed Jun 27, 2007 9:07 pm

yes, they are expensive if you ifgure in how many you will need

and they are one time use
Kenny_McCormic
Specialist 2
Specialist 2
Posts: 283
Joined: Wed Jan 03, 2007 8:59 pm

Wed Jun 27, 2007 9:15 pm

Flying_Salt wrote: That brings up another question, have you ever touched your series of charged capacitators?
if anybody did it will take them a while to type a reply because they will probably be missing a finger or two depending on the size of said cap bank
Spudgun on Crack
Private 4
Private 4
Posts: 79
Joined: Sat Jun 23, 2007 4:43 pm

Wed Jun 27, 2007 10:47 pm

HA HA kenny_Mormic

Yea all you need is four photocaps, i did this with six last year and it was awesome.

And if you want big capacitors i have 2 CDE 450v 5800uf capacitor's that are 8 inches long and 3 inches in diameter.

You won't hurt yourself with 60joules if you are smart you would build the whole unit then put the capacitors in and as for safety build a discharge switch that sends the current through a big resistor and you will be fine.

I need to go get more camera's to show you but it is not dangerous if you know what the hell you are doing.

And you won't loose a finger lol the worst that could happen with 1 cap is your arm feels numb for a few hours but six um it will probably be enough to stop a heart.
Post Reply