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Hey guys, I'm new here and I thought I would show off my first cannon. I finally convinced my mom to let me build it! She still doesn't like it...
The cannon is mixed PVC/ABS, the combustion chamber being the ABS part, and the barrel is PVC. I used 3 inch for the combustion chamber, with a threaded 2 inch connector for the barrel.
The ignition system is based on the guts of a taser from ebay. It broke after playing with it for about 5 minutes (I only paid $18 for it, what did I expect!) so I built my own control circuit for it and now it works better than ever! The output of the taser is hooked up to a spark gap made out of copper clad, with a total of 3 gaps. The system fires on the first push every time
The fuel is propane, through a metering system made out of 1/4" galvanized fittings, 1/2" PVC, and some black acrylic tubing. I made a long hose coming from the propane tank, which ends in a compressor fitting for easy removal, so I can leave the tank on the ground. The pressure gauge is upside down at the moment, and I intend to get a different one as soon as I have the cash. I also used tubing to go from the second valve into the chamber, in lieu of using an elbow fitting. If anything goes wrong it is easier to disassemble this way.
Also, I added a chamber fan to the system, controlled by a switch on the handle. All of the electronics, except the battery, are housed in the handle. A large aircraft switch with a cover arms the taser, but the fan works while it is armed or unarmed. A small red button on the bottom of the handle triggers the ignition.
Well, I think that sums it up pretty well. Pics are attached, and if you want to see the full size ones in all their glory, check my flickr stream here
If you have any questions, I'm more than happy to answer them.
Looks very nice especially being your first .......
My only recommendation would be to make the propane tank holder out of a magnet or something, I think there is a guide on burnt lake anyway again veryy nice
go and destroy some stuff
Very nice, and well put together. Only thing I would suggest would be to remove the stickers and maybe the lettering from the meter pipe, and this would look great.
Good job, and I hope you stick around.
I'm not a massive fan of the DWV, but if you aint gonna use pressure rated ABS is the way to go.
The barrel is fine but the chamber is unrated. I wouldn't bother changing it because abs has excellent failure characteristics.
Great work on this cannon and all of the innovations and nice little parts, hopefully you stick around and we see more from you!
Welcome to spudfiles!
I give my compliments as well. Nice job.
Two things though:
(1) you should not have epoxied the fan in place. If it ever dies (and it probably will) you are going to have a hard time replacing it.
(2) Do what Boom said with the tank. Click here for the link he was referring to.
Very nice for a first. Completely kicks my ghettos. Good work
Raise your horns if you love metal.
I like the effort here...pretty extensive use of advanced spudding techniques and technology for your first cannon build. I like your outboard propane tank/detachable hose system. The fuel meter as a whole unit is neatly configured and the handling ergonomics of the unit as a whole looks fairly comfortable.
Nicely done Ductape!!
The barrel is 6 feet long, calculated from a barrel/combustion chamber ratio I saw somewhere...probably burnt lake.
Hahaha yeah I realized after I took the pictures that I never took off the barcodes...I promptly did so. Also removing the lettering from the meter pipe is a great idea. I'll definitely do that soon.
Yeah after I built it I realized that I didn't use pressure rated ABS, but its all Home Depot had. I really wanted to make the whole thing out of PVC, but again, HD doesn't carry anything larger than 2 inches.
1. Meh, I really didn't use that much epoxy, and that epoxy isn't the greatest. And hopefully when that fan fails eventually (it was brand new when I installed it!) it will be time to build a new combustion chamber. But we will see...
2. I really like the idea of making a propane tank holder, but that requires me to buy another 10' section of pipe and with the way it's set up, the gun is lighter and it enables me to be able to use a large propane tank and a "tree" if you know what that is. Flexibility is key!
Sorry I don't mean to sound like a dick shooting down both of your ideas ...
Thanks! I'm the type of person who cannot leave anything "stock" so I went all out on my first try, as I knew I would take it there eventually. Saves some cost along the way
Oh and I had a great idea last night. I was at father's day dinner and someone was talking about marshmallow guns, which are normally work like blow guns. I thought that since I have a screw fitting on my chamber, I could make a marshmallow barrel and shoot (roasted) marshmallows as a less lethal ammo What do you guys think?
They don't fly very far compared to other ammo and fly like drunks driving. Getting friends together to shoot marshmallows through an old tire or other target is fun as they are very hard to hit.
At close range, they pack a punch and are able to punch holes in pop cans.
Edit, they also dent car doors.
Last edited by Technician1002 on Fri Jun 26, 2009 8:39 pm, edited 1 time in total.
Sounds like fun to me! I think I have some extra PVC laying around somewhere...I'll have to go get some reducers from the HD.
Oh and my friends and I shot the cannon last night Unbelievable. The thing is so powerful. Unfortunately we shot it at night so for distance all we could do is listen for the hit. It definitely went 200 to 300 feet at a low arc. We're going to take it out during the day soon, so be ready for a full video! We shot one last night, I'll post it tonight.
Glow sticks at night are great. Loaded some up in the apple cannon a couple years ago and got some kids involved. Load, pressurize, launch, and the kids would run to retrieve.
I about gave a parent a heart attack. We had colored glow sticks. We launched an orange one, the kids retrieved it and we re-loaded. While adding the air, a parent came by to investigate the fireworks having seen the glow of the last launch from the other side of the trees.
The parent watched the launch and the kids tore cross the field. It went up and started to come back down (duh!). I was informed it didn't go off.
I said, OK. They said, "but the kids !".
I said, "They see it.."
Now it got interesting..
It bounced on the ground and the excited parent said, "The kids! -- It didn't go off!"
I said, "They will pick it up and bring it back." I thought I was going to need a stretcher then when the kids picked it up and started running back with it held high.
I about got decked when they got back with it, much to our hysterical laughter.
Hahahaha that's a great story. I was planning on getting some glowsticks and putting them into the potatoes before launch. Also, I have a couple of videos I'm going to put on youtube as soon as I get out of class...one at night and one during the day. I google earth-ed (is that a verb now?) our launch spot and it said that I was shooting 200 yards, which seems like a bit much, but who knows, maybe its just that good I'm going out to shoot tonight again and I will try and get a more accurate measurement.
A potato 200 yards is about right for a cannon of this caliber. You actually won't get much further even with a more powerful cannon....drag and irregularity of the potato tends to limit its flight to the 200-300 range....on a good day.
I've been getting 250-300 yards on spuds. They tend to turn off course. The further they go the further off course. 25-75 yards off to the side seem to be the norm at range. I gotta try a rifled barrel. They tumble a lot. larger round spuds fly better with a larger barrel. Look for round bakers instead of #2 russets.
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