fuels help

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.
redalpha11
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Fri Aug 01, 2008 10:32 pm

i would like to know what youi think the best fuel is for a basic cannon.
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DYI
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Fri Aug 01, 2008 10:39 pm

MAPP gas. No question about that (unless you're worried about some insignificant price difference, but you'll have moved on to bigger and better things long before you use up one fuel cannister).
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TwitchTheAussie
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Fri Aug 01, 2008 10:42 pm

MAPP definitely. Although here Im using Lynx Pheonix and Voodoo deoderant together. Very good.
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starman
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Sat Aug 02, 2008 12:56 am

On a basic, un-optimized spud shooter cannon it's really hard to beat propane...you'll never realize the power difference from MAPP. If you add a fan, multiple spark gaps, and a burst disk, you could better capture the 10% or so extra power of MAPP. Even then, realized performace improvement will be marginal. You can play with a virtual design with HGDT and see performance difference for yourself.

MAPP is 3 - 4x the cost of propane. However, as DYI said, 1 canister of either one is likely to last you the practical life of the cannon.
THUNDERLORD
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Sat Aug 02, 2008 1:33 am

Lucky guy...Posts a one sentence question and gets responses from the pros!
I sense a poll on this one maybe. 8)

BTW I would have wrote propane.
Starting fluid for cars is good but unsafe for a lot of designs.
I'm interested in nitrous oxide. oxygen addition and even gasoline mixes. Certain spray starch(?) is said to be good.
I'm more into pneumatics but the idea of not necessarily pressuring seems nice lately. Besides I have a particular design in mind. :wink:
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TwitchTheAussie
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Sat Aug 02, 2008 2:15 am

THUNDERLORD wrote: I'm interested in nitrous oxide. oxygen addition and even gasoline mixes. Certain spray starch(?) is said to be good.
Just to point out Nitrous Oxide is an oxidiser not an actual fuel. And Ive never heard about this spray starch idea. Sounds interesting.
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spudgunning is like sex, once you've tasted, you can't wait til next time.
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THUNDERLORD
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Sat Aug 02, 2008 2:48 am

TwitchTheAussie wrote:Just to point out Nitrous Oxide is an oxidiser not an actual fuel. And Ive never heard about this spray starch idea. Sounds interesting.
It's a product for clothes in a spray can (can't remember name?).
Said to be good for spray and prays. That's all.

Enough on topic , If I had a chamber with a (Blow open) piston valve for use in few times hybrid, And was adding the oxydizer with the fuel, But never venting the chamber (besides what blows out with each shot) could it sustain ignition? (due to the oxydiser) Or will it eventually become too loaded with inert gas to get good performance?

BTW,Anyone pLZ i NDz hlp! Seriously I haven't tried it but must know. 8)
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Necrosis
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Sat Aug 02, 2008 3:39 am

Afaik, oxidizers actually bind with the explosive gas on ignition...

So I think you would need to vent to get the best performance.
Allthough we may be the most intelligent creature on this planet, we are also the most inconsistent.
To find peace within our existence we often create a logic that endangers our lives.
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Sat Aug 02, 2008 4:20 am

EDIT: ...once the chamber is filled with inert gasses of equal pressure to open the valve, no more fuel or oxidiser could be added without it opening the blow open valve. Bad for the design I was asking about.

So I'm not off topic, Most of the spray stuff used contains propane just in different brands and products.
BTW,Combustions are cool because you can say to yourself, "Now I'm cooking with gas!" :P 8)
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McFear
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Sat Aug 02, 2008 5:12 am

the best fuel i have used is start ya bastard by nulon. commonly found in woolies here in aus.

25% Ether and 75% petrolleum products.

Ross
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jimmy101
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Sat Aug 02, 2008 4:00 pm

I would have to say the best fuel, taking cost into account, is butane. For $4 you can make a complete meter system. Hard to beat that with any other fuel.

Even without the syringe, a butane lighter is probably a more reproducable way to fuel a gun since the gas flow rate is mush lower than with a typical aerosol can.

Like others have said, with a basic gun the extra power of MAPP won't be realized. So it isn't worth the cost.

In any kind of spray-n-pray setup the fuel power is pretty much irrelevant. How easy it is to get a semi-consitent amount of fuel in the chamber, and the absence of junk in the fuel, are the most important aspects of an aerosol.
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firey_ginga
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Tue Sep 02, 2008 3:07 am

iv bin looking around and i see most people use gas and liqiud fuels has anyone tried using a solid fuel (like gunpowder or a mixture of diesel and fertalizer), or can anyone tell me y i wont work.
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CasinoVanart
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Tue Sep 02, 2008 7:43 am

firey_ginga wrote:iv bin looking around and i see most people use gas and liqiud fuels has anyone tried using a solid fuel (like gunpowder or a mixture of diesel and fertalizer), or can anyone tell me y i wont work.
It will "work" but you won't be here to see it!!
Think big boom.

Diesel and fertilizer=explosive
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DYI
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Tue Sep 02, 2008 2:57 pm

iv bin looking around and i see most people use gas and liqiud fuels has anyone tried using a solid fuel (like gunpowder or a mixture of diesel and fertalizer), or can anyone tell me y i wont work.
I sent you a PM detailing exactly what you're dealing with in regards to ANFO.

As far as "sane" solid fuels like black powder, there's no reason that they won't work, but using such fuels would mean that it isn't a spudgun anymore, and this is a spudgun forum.

Please read the rules before posting again, it'll do you a lot of good here.
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kaa-boom
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Fri Sep 05, 2008 7:00 pm

the best ive used is right guard sport, but i got a can that was made in 2005 so it still works...for me its good enough cause it still goes far, still big bang ,still hear the crash of the potato in the trees 10 secnds later... :angry4: :angry4: :blob: :notworthy: :wav: :wav: :ky:
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