Sciencemadness Discussion Board - My Homemade air cannon

My Homemade air cannon

#maverick# - 4-7-2011 at 20:19

i guess this relates somewhat to science and thought id share it.

The gun runs on a piston valve system where air goes into the schrader valve and pushes the piston against the barrel which seals it and fills the chamber, then when i open the ball valve the high pressure goes to the low pressure and the piston kicks back and seals the outlet making the air in the chamber go to the barrel then shooting the projectile

my new piston with floating O-Rings:

4 inch 16 gram nail, all the way in 3 inches of wood from 15 yards at 300 psi, then hit the back stop and ricochet back to me

gun with the breech for breech loading open:

Horrible video of me denting aluminum with a paintball at 220 psi
http://www.youtube.com/watch?v=-0w46Q-ZsGY

hkparker - 4-7-2011 at 23:57

While a cool project, I do believe weapons talk is strictly against the rules here.

#maverick# - 5-7-2011 at 09:50

well if thats the case ill delete, i did not intend it to be a weapon or will it ever be used as a weapon but i can see how someone would be led to believe it is a weapon

[Edited on 5-7-2011 by #maverick#]

Bot0nist - 5-7-2011 at 10:48

You should try and rig some little sealed ampules of a pyrophoric compound or some 70% H2O2 and shoot at hay bails.

[Edited on 6-7-2011 by Bot0nist]

mr.crow - 5-7-2011 at 11:02

Nice! I love the piston design, I made something like that out of 3 inch PVC pipes in highschool. Im totally clueless when it comes to machining and don't even know how to buy o-rings so it never got any more advanced

The best design is just a 1 inch sprinkler valve modified to be pneumatically actuated and a 3/4 inch CPVC barrel. The CPVC pipe fits paintballs perfectly. The air tank is 3 ft of 2 inch pipe with a quick connect at the end. Paintballs can go through things like wood

#maverick# - 5-7-2011 at 11:29

Lol bot0nist I wish I had 70% h2o2. I was however putting m80s in the barrel and shooting them in the air great. Mr.crow that's an interesting design. I'll work on it. But for now I'm working on making a pump to go to 1000 psi. There is a design for it on spudfiles. But for 1k psi I would have to fit this gun with all steel components

hkparker - 5-7-2011 at 16:18

Quote: Originally posted by Bot0nist

You should try and rig some little sealed ampules of a pyrophoric compound or some 70% H2O2 and shoot at hay bails.

[Edited on 5-7-2011 by Bot0nist]

I wanna see that!!

I didn't report the post or anything, I think its a cool project, just fyi I've seen some stuff like this get torn down.

#maverick# - 5-7-2011 at 19:53

Ahh yea I realized hk. If anyone wanna donate 70% h202 I'll do it

Bot0nist - 6-7-2011 at 04:47

You ingenuitive. All you need is some glassware and ability to pull a vacuum. Boil off the water from 35% or even 3% until you approach 70% concentration by volume. I recommend not exceeding ~70% though. Even 50% is a touchy and can spontaneously ignite dry grass or the like. Use ULTRA clean glass if attempting this.

#maverick# - 6-7-2011 at 06:10

Quote: Originally posted by Bot0nist

You ingenuitive. All you need is some glassware and ability to pull a vacuum. Boil off the water from 35% or even 3% until you approach 70% concentration by volume. I recommend not exceeding ~70% though. Even 50% is a touchy and can spontaneously ignite dry grass or the like. Use ULTRA clean glass if attempting this.

I have the glass. What would be the best detergent to use to make it super clean. I have never done anything under vacuum but I do have a water Aspirator. Would this work?

Bot0nist - 6-7-2011 at 06:51

Search here for 'cleaning glassware". I think an acid (nitric) wash to remove organics followed by a good solvent (Pure, dry acetone) cleaning would be best. If you have 35% peroxide already, maybe piranha would work.

mr.crow - 6-7-2011 at 07:32

Aqua Regia is used to get rid of trace metals

Why are we talking about peroxide? Putting it in the air cannon is a dumb idea

Bot0nist - 6-7-2011 at 07:42

I believe I started it with my post about pyrophoric ampules. Just a suggestion for fun.

Mr. Crow, would you care to elaborate on the stupidity of this idea? Are you concerned with premature breaking of the ampule in the device, etc?

[Edited on 6-7-2011 by Bot0nist]

#maverick# - 6-7-2011 at 07:43

i dont know it would be fun with a ampule i have ampoules that fit perfectly just a little smaller than the the barrel

Rogeryermaw - 6-7-2011 at 08:14

i was under the impression that the ampoule would be the target. much less dangerous that way.

#maverick# - 6-7-2011 at 08:15

^^ that could work

mr.crow - 6-7-2011 at 08:42

Quote: Originally posted by Bot0nist

I believe I started it with my post about pyrophoric ampules. Just a suggestion for fun.

Mr. Crow, would you care to elaborate on the stupidity of this idea? Are you concerned with premature breaking of the ampule in the device, etc?

[Edited on 6-7-2011 by Bot0nist]

Yeah it might get pulverized and shoot a fine mist of H2O2.

Perhaps a regular glass tube could be sealed into an ampoule and put in a sabot.

It is still too dangerous IMO. Paintballs are fun enough

#maverick# - 6-7-2011 at 08:53

yea it is pretty stupid paintballs are fun but get boring after a while i now shoot the nails shown above straight thru 8 inches of dry oak hardwood

hkparker - 6-7-2011 at 12:39

If that ampule broke too early... well it would be more interesting but a lot less fun...

Making the ampule the target sounds like a good idea.

#maverick# - 6-7-2011 at 13:42

First thing first gotta get the h2o2 lol. Then I'll make an ampuole as the target

Bot0nist - 6-7-2011 at 13:49

Hope your a good shot, my ampules are tiny.

And do be careful when distilling your hydrogen peroxide. I know, I know, preaching to the choir...

#maverick# - 6-7-2011 at 14:20

I can just melt the top of a test tube and use it as an ampule. And I have a calibrated scope on it =)

Neil - 7-7-2011 at 16:25

Looks good, even if it is bound for detritus.

Think big

http://www.youtube.com/watch?v=1iqTogF-vW0

With a 2" barrel @ 20 PSI that contraption could (did) shoot a rubber chicken through heavy walled plastic rubber maid bins.