Cannon Ideas For a Friend

[rcman50166]

Hey all. I'm back to making the potato flingers again... at least until fall semester starts. Anyway, my friend wants to build a cheap reliable cannon just to see what all the hype about spudding is. Now the question is, what fits that bill and has the most power. It will either have to be a pray and spray or a simple pneumatic, like a burst disk or double ball valve setup. This cannon cannot exceed $50.

[SpudFarm]

simple marble piston valved gun?

or a sprinkler valved gun with a 3/4" barrel?

or a burst disk cartrige on a different scale?

mabe a huge hybrid with a 19" barrel as the pipe dream?

[starman]

Haven't we already gone over most of this with you here...Most efficient combustion?

It's just a simple potato gun. A full size 1.5" or 2" barreled pneumatic model will require a compressor. Otherwise the cost of a basic spray n pray or basic ball valve pneumatic will be basically a wash.

Therefore I recommend the spray n pray.

[rcman50166]

Well that was an experiment that epically failed when I failed to get enough cooperation from the spudding community. The world just isn't ready for what i was trying to prove in that thread i guess Anyway, my friend does have a compressor so, if cheap enough, pneumatic cannons are still a viable option

[DYI]

I'd say just a simple cannon with, say, 2" x 24" chamber, 180 degree bend, 2" burst disk (or even 1.5" burst disk, but it would look cleaner with a 2"), and then about 4' of 2" barrel. Nice and simple, and not incredibly lacking in power (figure 500 ft/lbs or so, but that's just a rough guess).

[rcman50166]

Thank You. These are the recommendations I am looking for. What do you figure a burst disk of recommended size would cost.

[starman]

If you're shooting potatos, a "high powered" burst disk gun is really anathema....it's too much power too quickly. When I shoot potatos with a burst disk adapter, I get mostly vaporized, small chunks of a potato projectile and very poor distance.

Your best bet for "performance" is a longer barrel, say 5 or 6'. This will give the potato more time under the influence of pressure, but still allow it a slow enough build up to stay intact. This will allow you to put holes in 5/8 plywood with a potato at 75'.

You won't gain much if any distance however....drag being your enemy there.

Also, 1.5" is your ideal barrel diameter for potatos.

[rp181]

triggered burst disc with 2 unions.
on a side note, with one 3/4in burst disc, with 2 layers of ALU foil, i can pump it to ~60PSI without it bursting, and when i jerk the union loose, it bursts, maybey you can try something like that.

[jook13]

my vote goes towards a modified sprinkler valve. using the blowgun as a trigger is just awesome in my book.

[Mr.Sandman]

i think you should make a spray and pray. i think begginers(like me )
are more excited in loud and forceful cannons like spray and pray plus i think they are a lot easier to operate and make. .Hope this helped.


EDIT: 100th post yay
PS: yes i like using this emoticon HA HA

[Gippeto]

My copper gun cost less than $30 to build.

Great fun/$ ratio.

[starman]

i think you should make a spray and pray. i think begginers(like me )
are more excited in loud and forceful cannons like spray and pray plus i think they are a lot easier to operate and make. .Hope this helped.


EDIT: 100th post yay
PS: yes i like using this emoticon HA HA

Perhaps you could start trading a few of those for some real live capital letters.

[Demon]

For me, the easiest to make is the pneumatic BRASS ball valve, not the pvc one.

just buy :

2 tubes of pvc of 1 inche and 12 inches long
2 male 1" adaptors
1 brass ball valve
1 pvc cap of 1"
and one schraeder valve(of course)

steps:
dig a hole of 11/32 in the middle of the cap and insert the schraeder valve in it.
glue the cap to one of the 2 tubes and put an adaptor to the other end.
screw the ball valve to the adapter on the tube and screw the other one the other thread of the ball valve and put the canon in it (no need to glue this one).

and VOILA it costed me 30 dollars and shoots 200 yards away:
to fire it shoulder mount it, in this position, its very easy to open the valve