Want build a signal cannon

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.
Bangotwago
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Sun Dec 30, 2012 4:24 pm

I built my first spud cannon yesterday and I think I have found enough info on here to get me thru that project. What I really want to do is be able to convert what I have into a signal cannon. I have a chamber that is 3548ml. I tried masking tape at the barrel to chamber connection and the boom is less than impressive.I have duel ignition with machine screws using a battery powered 12kv grill igniter. No fan yet and I'm having issues getting both machine screws to spark.

I'm metering the propane in with a 3/8 street L and a 6" 3/8" nipple and two 3/8" ball valves. No regulator. I've tried one and two shots into chamber with my metering device. One shot is the ticket.

It fires spuds but I'm less than impressed. I just did the volume measurement on my barrel and found out I need a 74" barrel and I only have a 46" so I will fab a barrel and try the spuds again.


Is my problem air/fuel ratio?

Is it because I'm not regulating the propane? Bottle pressure too much?

Is the 12k spark not enough?
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jrrdw
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Sun Dec 30, 2012 4:47 pm

Experiment with layers of aluminum foil to reach desired sound, the shorter the barrel the louder.
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Zeus
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Sun Dec 30, 2012 5:17 pm

The problem is your metering, you need a gauge at the least.
/sarcasm, /hyperbole
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D_Hall
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Sun Dec 30, 2012 6:36 pm

Bangotwago wrote: I just did the volume measurement on my barrel and found out I need a 74" barrel and I only have a 46" so I will fab a barrel and try the spuds again.
What does that even mean?
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Technician1002
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Sun Dec 30, 2012 8:05 pm

Does anyone else get an ad on this page on a banned topic?

Blackpowder Cannon
[url snipped]/free_shipping
Celebrate July 4th & All Events! Made in USA since 1912

Is there a way for SF to ban some ad types?
Bangotwago
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Sun Dec 30, 2012 8:37 pm

Sorry d hall. I meant volume on chamber not barrel.
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Zeus
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Sun Dec 30, 2012 8:40 pm

Well it's legal in the US, and I'm allowed to mention my rifles, so to be honest I can't see a problem.
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Mr.Stark
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Sun Dec 30, 2012 10:20 pm

Sadly it may not be legall to mention your rifles for long.I hope this doesn't violate forum rules but as for signal cannons nothing beats the price or ease of a thunder mug. google it they're so much fun. Back to your rifles if they use mags stock up same for anything else. The newest version of the ban is trying to make anything with mags illegal and the sale of mags. You can keep what you have but will have to register and submit new backround check. Isn't it nice when a man who has a whole secret service to protect him and his family says you don't need guns to protect yours lol. A law for gun control only effects the law abbiding citizen not the criminals that caused it. Well sorry for my rant.
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Zeus
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Sun Dec 30, 2012 10:26 pm

I'm Australian, so we went through this in 96, it hurt a lot.
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Essohbe
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Sun Dec 30, 2012 10:41 pm

You should've been buying up stuff long ago.
Australia that is your fault for putting up with it in the first place.
They came for your guns and you handed them right over. Live and learn.

New AWB is uncontitutional and won't stand. There will be a civil war over it if they pass it.

To the OP, if you bolts aren't sparking maybe try something made of copper? I don't know but I was wondering that today, thinking about just going copper to begin with on mine and not even messing around with anything else even though I figured machine bolts are easiest since I have a bunch laying around.
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D_Hall
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Sun Dec 30, 2012 11:53 pm

Essohbe wrote:New AWB is uncontitutional and won't stand. There will be a civil war over it if they pass it.
And yet, it is almost identical to the AWB that has been in effect in California since 1989. Oddly enough...it has stood.
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Mr.Stark
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Mon Dec 31, 2012 2:37 am

Yet again those laws only effect the people that obey them, good people who you don't have to worry about. Criminals and those who wish to do the bad that caused this don't care about a law. I will remain armed for as long as i feel a reason to defend myself. I don't understand how the second amendment gets trampled and nobody cares but if they said hey we want to say what you say or right it would be an outrage. My stance on gun control is kick my door in to take them and you can watch me control the **** out of it, because i know it's illegal to violate the constitution.
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D_Hall
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Mon Dec 31, 2012 3:32 am

My only point(s) were (a) that the courts have so far upheld the AWB in California so the court's opinion is that it is in fact constitutional (it's not your opinion that matters, it's the court's opinion); and (b) there hasn't been so much as one rebellion here so I'm better that the talk of civil war is just that: talk.
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jrrdw
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Mon Dec 31, 2012 7:42 am

Lets get back on topic please.......thanks. No need for threadjacking.
Essohbe
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Mon Dec 31, 2012 11:19 am

When the courts are stacked full of leftists then that is the quality of opinion they will rule with. Just because a court rules on something doesn't mean it's correct. Look how many cases have been overturned by other/higher courts.

If they had their absolute way you wouldn't be allowed a spud cannon even. Australia's ban is worse than CA, they actually had to turn intheir handguns and nobody is allowed semi autos even. Have to be single shot.

Don't compromise and don't say "it's not that bad." Yes it IS bad.
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To the OP:

Did you figure how much gas you need to meter also? That's something I had to have help with. Then you have to convert Bar to PSI I think after doing the math.

Do you have a fan too? Doesn't hurt to put one in. I think everyone using propnae should have one. My buddy has this spray and pray one that doesn't really take allot of work to build but if you're going to put the time into a good cannon with a propane meter then stick a fan in there, know what I mean?
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