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Homemade spud gun.

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Arcstarter

Tue May 27 2008, 06:26AM

Registered Member #1225 Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253

Made from 2 inch pvc pipe, spark plug, neon transformer, and some mapp gas as propellant and potatoes cut into fourths as 'ammo'. A few minutes to put transformer together with cap(not necessary, but i found much quicker ignition times, due to the little gas that is left in the pipe after the cap has squeezed most of the gas out. I am now using clay, as it is reusable and it flies further and faster.

flannelhead

Tue May 27 2008, 11:32AM

Registered Member #952 Joined: Mon Aug 13 2007, 11:07AM
Location: Finland
Posts: 388

Nice!

I've experimented with a disposable camera flash board as an igniter. So basically the xenon bulb is replaced with an air gap and the trigger transformer wire is between the two wires coming from the cap. However, it's not as reliable as it could be. A NST sure works reliably, but it's not so portable.

Now you could measure the kinetic energy of the projectile. Then calculate somehow the energy stored in the propellant and this way calculate the efficiency!

Solidacid

Tue May 27 2008, 12:26PM

Registered Member #1430 Joined: Sun Apr 06 2008, 11:12AM
Location: Ã…rhus, Denmark
Posts: 102

cute little gun ;D

i built a spudgun last year, it shoots about 700-800 meters with hairspray :D.
i used to ignite it by charging a photoflash capacitor and shorting it on an ignition coil to get a red 5cm spark

teslacoolguy

Tue May 27 2008, 07:11PM

Registered Member #1107 Joined: Thu Nov 08 2007, 10:09PM
Location:
Posts: 792

I built a handhelld air powered spudgun a couple of weeks ago and with a 1/2" barell it can shoot a rock through 1/4" plywood from 15' away.

Shaun

Wed May 28 2008, 01:24AM

Registered Member #690 Joined: Tue May 08 2007, 03:47AM
Location: New Jersey, USA
Posts: 616

I have 6 of these insane ASCO high-flow quick exhaust valves with a 1.5" porting. I've been told they are like the best valve you can get for air cannons without making one yourself. At 140psi, the damn thing sounds like a thundering *CRACK* from a rifle.

With a 1.5" potato barrel, it rockets them 500 yards easy, and with a 1" steel ball bearing in a matching barrel i don't know range but it rips through 3/4" ply at 50psi.

Ill have to make a video tomorrow and post it, it like the coolest thing ive ever made.

EDIT: I should probably mention its like 4.5' long!

rp181

Thu May 29 2008, 03:17AM

Registered Member #1062 Joined: Tue Oct 16 2007, 02:01AM
Location:
Posts: 1529

A NST is only a bit over powered...
I made a pneumatic one, at 40 PSI, it went through 1in pine.

teslacoolguy

Thu May 29 2008, 03:36AM

Registered Member #1107 Joined: Thu Nov 08 2007, 10:09PM
Location:
Posts: 792

I use sprinkler valves

mainly because they are cheap and work just fine. Here is a picture of it for inspiration.

Arcstarter

Fri May 30 2008, 12:35AM

Registered Member #1225 Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253

I made a new one with a y joint as a combustion chamber and a 1 inch pvc pipe. Sounds like a rifle just not as loud. It shoots the potato so hard, when it hits anything it explodes. I shot it straight up and it took around 12 seconds till it hit the ground. It even has some kickback. I am still using mapp gas. I do a 4 second 'spray' and twist the cap on. To ignite i use a magneto with 6 turns on the core as primary and i discharge a 600uf cap charged to 50 volts through it. Not very hot spark but it works every time. I use a sparkplug for ignition. I will post a video once i get more potatoes

rp181

Fri May 30 2008, 02:18AM

Registered Member #1062 Joined: Tue Oct 16 2007, 02:01AM
Location:
Posts: 1529

today was first day of summer vacation, so i got bored. I used a 2 liter with 3/4in union(burst disc) and ball vavle if i feel like holding it. Barrel is 1/2in, ~6ft. I Shot a 1ft piece of rebar at a fence from 20ft. away, it went through. Also almost got hit by a marbel from richoche.

Arcstarter

Fri May 30 2008, 02:47AM

Registered Member #1225 Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253

rp181 wrote ...

today was first day of summer vacation, so i got bored. I used a 2 liter with 3/4in union(burst disc) and ball vavle if i feel like holding it. Barrel is 1/2in, ~6ft. I Shot a 1ft piece of rebar at a fence from 20ft. away, it went through. Also almost got hit by a marbel from richoche.

Be careful! Yea i had alot of fun with my new gun. I shot a can and it folded around the potato which flew out still! I also put a potato in the barrel and but a few different items in it. I also shot a potato so high i didn't see it! It is great fun!

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