a few basic questions

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.
irishguy
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Fri Sep 21, 2007 8:36 pm

how long should my combustion chamber be if im using a 4ft 2inch barell and the standered orange pvc pipe chamber and also will butane work
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DYI
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Fri Sep 21, 2007 8:41 pm

You need a chamber that is about 120 ci if you are using metered propane. If you are using aerosol fuels, your chamber should be around 150 ci.
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frankrede
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Fri Sep 21, 2007 9:09 pm

Orange pvc?
I have never heard of it?
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Fnord
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Fri Sep 21, 2007 9:37 pm

You mean orange pvc like this?

[youtube][/youtube]
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trae08
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Fri Sep 21, 2007 9:42 pm

that actually looked like a ceramic pot... and it seemed like he expected the explosion to happen with all the stuff he was wearing and wrapping his leg up.
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Fri Sep 21, 2007 10:02 pm

Orange pvc is electrical conduit i think, there would not be a pressure rating :? Might be fine for a combustion though- as long as i'm not using it!
Search "EVBEC" irishguy.

Welcome to Spudfiles :D

Edit: That guy is crazy, using a ceramic pot as a chamber.
I wonder if his name is DARWIN :lol:
irishguy
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Fri Sep 21, 2007 10:43 pm

as far as i know here in ireland that is run of the mill sewer pipe and has a legal minunum requirement of 110 psi im not a 100% shure thow you cant get the white stuff here. also the pipe is more expencive it cost me 75 dollars to build my basic cannon so i should have a chaber about 2 ft long for a 4ft barell the barel is 2 inches and the chamber 4
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Fri Sep 21, 2007 10:49 pm

My eyes hurt :( And my brain is burning :angry4:
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Best of luck with your new launcher :)
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MikeNice
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Fri Sep 21, 2007 11:33 pm

not too sure about the pvc you are using but I've been doing 4" x 18" chambers for about 5 years with a 2" x 48" barrel. it's off a bit from the magical 1:1.5 C:B ratio but it works really well.
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Sat Sep 22, 2007 1:22 am

_Fnord wrote:You mean orange pvc like this?
Most succinctly put, touche :)
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Sat Sep 22, 2007 1:34 am

Novacastrian wrote:My eyes hurt :( And my brain is burning :angry4:
Two words, spell-check.
Best of luck with your new launcher :)
That was one word with a hyphen in the middle, please don't be a hypocrite. :roll:
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Purely for emphasis Turbo, however if you break down the word it could be taken both ways, meh
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Sat Sep 22, 2007 12:40 pm

irishguy wrote:how long should my combustion chamber be if im using a 4ft 2inch barell and the standered orange pvc pipe chamber and also will butane work
See this thread http://www.spudfiles.com/forums/viewtop ... tml#120201

Don't know what the diameter of "standerd orange pvc pipe" is so kind of hard to answer the question.

Assuming "standerd orange pvc pipe" is 4" ID and the barrel is 4 feet long piece of 2" pipe then the length of the chamber is about;
(0.80)*1<sup>2</sup>/2<sup>2</sup>*4' = about 10 inches.

If your are more than 12 years old you really should be able to do this kind of math yourself.
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spanerman
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Sat Sep 22, 2007 1:35 pm

Hi, iff your are from the uk(or island) the orange soil pipe 'can' be used for combustions....but you would be better off looking for pressure rated pvc or solid wall abs pipe.....im sure the guys at www.uksgc.co.uk would be able to give you help on finding these pipes...
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dongfang
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Sun Sep 23, 2007 3:47 am

Hi,

I Europe, orange PVC pipe is drain/sewer pipe for underground use.

It´s OK for fuel/air combustions up to 110 mm. I actually had an 40% oxygen enriched mix in one, and it didn´t blow up, BUT THAT MEANS JUST THAT I WAS YOUNG AND FOOLISH, NOT THAT I CAN RECOMMEND THAT PIPE FOR ANYTHING BEYOND PLAIN FUEL/AIR COMBUSTION GUNS. The experiment just confirmed that it could withstand twice the blast of a fuel/air combustion at least a few times, so I believe it is OK for a plain fuel/air combustion.

It is too weak for anything else, and as the movie shows, >> 110 mm is not strong enough for combustions either. The thing they used was a coupler for a large (> 200 mm it seems) sewer pipe.

Regards
Soren
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