Show us your pneumatic spud gun! Discuss pneumatic (compressed gas) powered potato guns and related accessories. Valve types, actuation, pipe, materials, fittings, compressors, safety, gas choices, and more.
Here's the first air cannon I have ever made. I made it a while ago (I was a 7th grader, with hardly any help). I just discovered this forum recently, so I decided to post it. Nothing special.
Specs:
Air reservoir: 4" PVC pipe, about 5-6 feet long
Valve: regular sprinkler valve
Barrel(s): Interchangeable! (w00t) one is 1 1/2", the other is 2", both about 6 feet long
I only Pressurize to about 40 psi these days, because the PVC is old. do you think I can go any higher? (safely?)
oh yes...the movies..kind of retarded, but here they are, if you want them, (even though I doubt you do)
[youtube][/youtube]
[youtube][/youtube]
Attachments
interchangeable barrel detail
valve detail
most of the cannon...doesn't fit in the room...
Last edited by KurlyQ on Mon May 19, 2008 4:32 pm, edited 6 times in total.
but other than that it is actually a pretty nice gun
the barrels could be longer and the sprinkler is constricting flow like crazy but its your first, you can always improve next time
Looks like you have some DWV piping...change it next time. DWV is Drain Waste and Vent, which doesn't take pressure. I'm glad you've only charged it to 40 PSI...any higher than 60 will be...
BOOM.
Scrap the death trap and build a new one w/ pressure rated pipes.
4'' Air Chamber is overkill for a pneumatic.
Old PVC is safe to use
The pipe may be SCH 40 but the fittings look like DWV. Look on the ring on the fitting where the pipe slips in. Anything that doesn't say NSF-PW has to go. The Spud Wiki also has some useful ways to spot DWV, such as the flared fittings and the fact that your reducer bushing doesn't slide all the way into your coupling.
Oops, I see you have been beaten about the face and head with a wet noodle by the DWV police, right out of the shoot.
They are referring to the tee and bell reducer you used to transition from your tank to your barrel...maybe another part or 2 in there. Officially, those parts have no pressure rating. Your pipe and tank endcaps are fine.
In practice, you'll find that there are practically NO 3 or 4" connector parts that are pressure rated available at your local Home Depot or Lowe's...the pipe and endcaps are the only parts "rated" there. The biggest issue with the non-rated parts is the fairly shallow or loose fitting weld sockets. DWV parts that get sort-of a pass are inline couplers and female cleanout couplers. Go to a plumbing supply shop to find pressure rated tees and use reducer bushings/couplers to go from one size pipe to another, avoid the bells.
Also, you'll find combustion guns get almost a total pass on any PVC parts used...pressures rarely exceed 30-40 psi during the shot and for only a few milliseconds. A pneumatic however is holding back air for much longer and is at your whim as to how much you force in there.
Welcome to Spudfiles! Keep your pressures in this gun in the 50-60 psi max range and you'll be fine.
Edit: As has been stated, the 1" sprinkler is choking your performance in this design. I wouldn't waste much effort replacing it. Just move on to your next gun project.
Coodude26 wrote:
People who laugh really hard at stuff that pisses you off/you getting hurt, who then say "I'm sorry, I can't stop" but you know they easily could.
Mr.C: That's not as easy as you think. It's like me kicking you in the balls and telling you to stop crying.
MaxuS the 2nd wrote:Dude, I don't mean to be mean but that's one of the ugliest guns I've ever seen.
Surely you could have used less components for a better looking gun?
Lol. I'm sorry, but that's the first thing i thought as well. Seriously, scrap the DWV bomb and use the pipe to make a safer, better looking cannon.
OuchProgramme wrote:Looks like you have some DWV piping...change it next time. DWV is Drain Waste and Vent, which doesn't take pressure. I'm glad you've only charged it to 40 PSI...any higher than 60 will be...
BOOM.
Old PVC is safe to use
\
Sorry to burst your bubble, but on my first REALLY bad pneumatic I had a DWV reducers on the chamber and I went to a gas station, filled it to 170!! and rode in the CAR with it! and I was fine, by the time I got home it had leaked about 70 PSI but still it had 170 in it, in my hands, in a car.
Yes I agree this cannon sucks , but still, I made this cannon a WHILE ago...way back in 7th grade! (I'm in 10th grade now).
this cannon might suck comparatively, but personally, I don't think it sucks for a 12-13 year old with hardly any help.
