How much would it cost to make a....

Boom! The classic potato gun harnesses the combustion of flammable vapor. Show us your combustion spud gun and discuss fuels, ratios, safety, ignition systems, tools, and more.
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starman
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Sat Aug 09, 2008 11:24 am

noob of noobs wrote:I'd recomend you try a pneumatic or a hybrid since they trump combustion in power and range.
More power isn't going to help here...and if you "encase" a potato then you really aren't shooting spuds anymore....there could be anything in that encasement.

I also challenge your contention that a pneumatic would be more effective shooting spuds as a broad general statement.

Drag and fragility will always limit the spud's distance. Go with a longer 6' to 8' barrel on a normal combustion or slow to medium valve pneumatic and a tight fitting spud and see what you see. The idea is keep the potato intact, best chances for most distance.
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Sat Aug 09, 2008 12:02 pm

I've got to agree with everybody else on the range issue. It's unlikely that a spud was launched 300 yards, 300 feet is a heck of a lot more likely.

1. It is darn hard to see a fist sized object at 300 yards.
2. No matter how much oomph you put into a spud it won't carry that far since the sectional density is too low. Enough oomph and all you get is spud plasma coming out'a the barrel.
3. A surprising number of people have difficulty telling the difference between yards and feet. :roll:

If you really want 300+ yards then spuds and tennis balls are out. Golfballs can do that range, a baseball maybe can do that range. A combustion gun for that range would need to be pretty big, with a barrel that is 6~10 feet long.

I would think that, in the US, you could build the combustion for perhaps $30. The biggest cost would be the igniter (~$12). Accurate fueling can be done with a disposable lighter and a $2 syringe (versus perhaps $30 for a full blown meter system).
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Sat Aug 09, 2008 11:59 pm

I used a simple long nose lighter for my cannon, the trigger mechanism is cool for a bazooka style handle, plus they're only like 3 bucks. I made a simple combustion for under $15 since Home Depot sells those 2 foot sections and small diameter pipe is cheaper. 350 Yards seems a little far, that distance and speed is gonna create some massive recoil too. I've broken endcaps while bracing mine against the ground (water is very heavy) recoil is dangerous.
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Sun Aug 10, 2008 1:25 am

Would it be easier to launch a water balloon or a spud 350 yards?
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MrCrowley
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Sun Aug 10, 2008 1:48 am

Pooper wrote:Would it be easier to launch a water balloon or a spud 350 yards?
Well for starters neither would probably survive such a launch.

So the answer is not really applicable.


If you want to launch a golfball 350 yards, that's a lot easier. A decent advanced propane metered combustion could do it, or a piston valved pneumatic like mine here:
http://www.spudfiles.com/forums/v-a-l-p ... 14702.html
http://www.spudfiles.com/forums/viewtop ... tml#100616
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Sun Aug 10, 2008 9:35 am

freeze the spuds would be the only thing you could do.. but golf balls does not go as far as people think.. when i shot them with my hybrid at 3x they went 400 yards (not that much considering the size) but if you can get a lead slug up to some speed it will go FAR..

another thing could be a dart..
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Tue Aug 12, 2008 4:30 pm

jackssmirkingrevenge wrote:... and the fact that potatos tend to vapourise if fired above a certain velocity :roll: :D
Now I wonder, what is that velocity?
It would be different for different diameters of potato and I also guess longer spuds will better manage to stay intact.

Hey, we could create an formula:
v = r * l * c
v= minimal vaporizing velocity
r= radius
l= spud length
and c is the well-known universal "spud vaporizing constant". :)
Ofcourse, the formula will need some tweaking, but this is the start. :D


Hmm, I think also the pressure behind the spud plays a big role so that'll also have to be put in...
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Tue Aug 12, 2008 5:46 pm

By the questions Pooper is asking, the question for me personally, is weather or not I believe this guy is capable of safely constructing a cannon at all, let alone one built to throw something 350 yards. First you should focus on, Pooper, searching the website THOROUGHLY and browsing through your local hardware stores and taking a good, hard look at what's available, and exactly what it is. I apologize if I am incorrect, I just don't want this guy going in and building a pneumatic or hybrid and using DWV on it and getting himself injured, or worse.
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Tue Aug 12, 2008 7:20 pm

I apologize if I am incorrect, I just don't want this guy going in and building a pneumatic or hybrid and using DWV on it and getting himself injured, or worse.
You are incorrect. Whenever you have the chance to help along natural selection, by all means, do so! By instructing this guy on how to build dangerous devices that he doesn't understand, we're doing a favour to humanity in general.

In that spirit: I believe the OP's simplest option is to get a water cooler, a few cans of hairspray, and a television flyback generator. Spray in way too much hairspray, then seal it up, turn on the flyback, and pump in air with a bike pump on a short hose until it ignites. If you don't have the brains to accomplish even that, I'll tell you how to make some unstable energetic compounds over the PM system :roll:
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Sat Aug 16, 2008 3:20 am

is there anyway of theoretically finding out how much distance i would get with a spud if i know the distance that a tennis ball went.

tennis ball (67g) went 180m at 5 degrees to the horizontal (video footage on youtube, search for scab1991 and watch) if i were to make a slug thats maybe 150 or 300 grams, is there anyway to hypothesise how far it would go.
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TwitchTheAussie
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Sat Aug 16, 2008 3:59 am

Mate use HGDT. Theres plenty of links. And DYI your a cold, cruel darwinist :lol:
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Sat Aug 16, 2008 5:21 am

that was lovley said DYI :lol:
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Sat Aug 16, 2008 5:59 am

psycix wrote:Now I wonder, what is that velocity?
It would be different for different diameters of potato and I also guess longer spuds will better manage to stay intact.

Hey, we could create an formula.
I have actually been thinking about that... I was wondering about rifling rates for potatoes and I was wondering what the limit was before the spud simply spun itself apart - I think I'm close to perfecting the formula for that at least.
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Sat Aug 16, 2008 6:06 am

is there a thread for HGDT cause its kinda confusing when not using it for a hybrid. i know it can be done, cause i have had people do it for me, but its kinda confusing to use for the first time.
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Sat Aug 16, 2008 6:22 am

I'll tell you how to make some unstable energetic compounds over the PM system
:lol: Which one would you recommend to him?

If you really want to reinforce the natural selection, maybe you should publish a small book and add it as a free addition to newspapers: "Cool stuff you can do with acetone and hydrogen peroxide."
A small line on the bottom of the cover reads:
"By reading this book I agree to be aware of the risks and I am fully responsible for any damage or injury caused by any actions taken based on this book."
A coupon for getting all necessary ingredients for half of the price is included.

For survivors, release a second book about NI3...
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