electrothermal bb launcher idea

[st.croixsurfer]

To start off with i am in no way shape or form asking how to build a cannon ,and i am in no way asking for plans. I am simply and politely asking for the helpful input of people who know what they are doing.

I had an idea for an electrothermal {gun} so to speak that would launch airsoft bb's at rather high velocities with no intention to be shot at people of course.
I plan on using a six millimeter barrel. If anyone has ever bought six mil pipe what is a good place to get it?
Right now i am in possesion of a 70 joule capacitor bank and i am wondering if that will be enough...
I plan on using a trigatron to trigger the capacitors. If anyone has had any experience with making a trigatron what were some of the problems you encountered if any?
I am going to use steel wool for the material that the cap bank will discharge through.
If you have any helpful insight into any problems i may encounter during the production of such a device please by all means leave a comment below stating such.

[SpudFarm]

the best person to talk with is Larda.

if you want i can PM you his MSN adress, i am sure he will help

but he used 2880 joules.

[psycix]

2880 joules, 70 joules, whats the difference?

Maybe, instead of an ETG, you could try a coil gun. But that will only work with ferromagnetic projectiles ofcourse, like nails. (Not sure if steel bb's work?)

[THUNDERLORD]

IDK about a "Trigatron" but this guy called "the Judge" on here knows about flex capacitors.

[Sticky_Tape]

2880 joules, 70 joules, whats the difference?

Maybe, instead of an ETG, you could try a coil gun. But that will only work with ferromagnetic projectiles ofcourse, like nails. (Not sure if steel bb's work?)

Steel is ferrous so yes steel bb's would work. He wouldn't need to use a ferrous projectile he could use sometype of ferrous sabbot basiclly just a slug behind the bb. Maybe the slugg would be on a leash so at the end of the barrel it would stop sort of like those toy popguns you sometimes see in cartoons.

[TurboSuper]

I dunno, coil guns only give you limited power unless you decide to multi-stage them. I think an ETG is simpler for launching things really fast. Plus it has one helluva muzzle flash

I find the best barrel for BBs to be brakeline tubing. I used some for my strafer, works beautifully.

[Larda]

2880 joules, 70 joules, whats the difference?

Actually i used 28 800 joules.

[st.croixsurfer]

i can get more capacitors.

Larda's seems wicked powerful a little to powerful than i intend mine to be, if i made something like that my mom would have a fit
i'll try with 200 joules


p.s. has anyone tried to get free cameras from cvs? got any tips on that?

[rp181]

pfft, 28.8KJ and 70 joules are practically the same thing

BTW, *a company* said that they would provide me with caps once i get a letter from school, i plan on getting 16 400v 15000uf (same values as yours) caps (i could get more pssiably, but those caps are HUGE!)

anyway, back on topic, coilgun with BB's suck, cylinders are better. Electrothermal wont be all that great with 70 joules, more like a little light show.

[st.croixsurfer]

yeah im going to get a lot more caps

[Hotwired]

Depends how small the bore is.

I'm partway through linking up 100 capacitors for a 550J bank which will be for a few experiments.

[st.croixsurfer]

has anyone tried to get the used disposable cameras from your local cvs or wallgreens?

[rp181]

lol, a hundred caps?
1) if there in series, dilectric breakdown will probably be exceeded, ESR will be high
2) if there parrallel, they will unevenly charge unless theres balancing resistors.
3) a cap will probably fail and it will be hard to find it/repair.

[st.croixsurfer]

my intended projectile will be only .2 to .3 grams is a large amount of joules that necessary?

[rp181]

the thing with electrothermal is large energies are still required to vaporize the fuel. Try it, it will work, but you might not get the speed you would expect. 70 joules is pleanty for a coilgun, try that with cylinder projectiles, you will like it, its also compleatly silent.