el cañón de la combustión de 55mm

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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jackssmirkingrevenge
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Fri Nov 14, 2008 7:32 pm

This is my last planned project here, nothing exceptional or innovative but hey. 55mm bore, 1.30 metre barrel and a 95mm chamber giving a C:B ratio of around 0.7:1 - I'm away for the weekend so it will be tested on Monday.

The endcap is a detail of typical JSR epoxy construction, the end is sealed with a disc of foam cut from a meat tray, over which a roughly 10mm thick layer of epoxy is poured. I added wood screws all around the casting for added strength and adhesion. Ignition is by piezo hacked from a cigarette lighter, I cast a housing using wire wrapped around a foil cup as a contact, in order to make it removable. The second bolt is there to cover a port for fuelling (butane from a lighter refill canister metered with a syringe) and venting.

Test results and damage pics/frustrated rants about another failed project to follow in a few days :)

edit: It works :D

[youtube][/youtube]
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looking down the barrel, note the lovely overkill thick walled piping, all courtesy of the company :D
looking down the barrel, note the lovely overkill thick walled piping, all courtesy of the company :D
businessend.JPG (20.57 KiB) Viewed 5266 times
end cap with ignitor fitted
end cap with ignitor fitted
endignitor.JPG (17.76 KiB) Viewed 5266 times
end cap with ignitor removed
end cap with ignitor removed
end.JPG (15.72 KiB) Viewed 5266 times
Last edited by jackssmirkingrevenge on Sat Nov 16, 2013 5:12 am, edited 2 times in total.
hectmarr wrote:You have to make many weapons, because this field is long and short life
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Pyro Ninja
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Fri Nov 14, 2008 7:40 pm

True JSR style. :)
It should be fun, good work.
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Carlman
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Fri Nov 14, 2008 7:51 pm

nice mate!

cant wait for damage!
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Aussie spudders unite!!
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mark.f
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Fri Nov 14, 2008 7:58 pm

¡Muy bien!

Quiero esto cañon. ¿Lo vas a darme, no?

Grammar is probably appaling, but yeah... good job. How did you connect the chamber to the barrel?
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Ragnarok
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Fri Nov 14, 2008 7:58 pm

Bona fide JSR Semi-ghetto work - passes muster with me.
Now show us some things poking some holes in other things.

... And now, for your next trick, get your mind above your waist line. ;)
Does that thing kinda look like a big cat to you?
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jackssmirkingrevenge
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Fri Nov 14, 2008 8:08 pm

markfh11q wrote:How did you connect the chamber to the barrel?
Easy, wrapped the barrel tightly with duct tape (and folded paper, otherwise it would have cost me a fortune if it was just tape alone) to the thickness of the inner diameter of the chamber, glue it in with anything (araldite, PVA glue, silicone sealant) then pour epoxy to about 10mm thickness to seal everything in.
... And now, for your next trick, get your mind above your waist line
Like that's ever going to happen :D

Anyways, I'm off to Lisbon - which to my ill-concealed disappointment, I discovered has apparently got nothing to do with girl-on-girl action - for the weekend, so see you all on Monday :)
hectmarr wrote:You have to make many weapons, because this field is long and short life
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Gippeto
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Fri Nov 14, 2008 8:13 pm

Where there's a will, (or is that a Jack?) there's a way. :wink:

Nicely done Jack, robust looking.

Awaiting monday and the damage shots.
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SpudUke5
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Fri Nov 14, 2008 8:27 pm

Me gusta tu cañón. Tienes muchas cosas para hacerlo. Me parece que la patata va a ir muy lejo. Quiero un canon de combustión pero necesito terminar mi cañón pero no puedo porque no tengo las materiales para terminarlo. Esta es el colmo! Qué combustible vas a usar dispararlo?

What a mouthful :) (Spanish 3 can be useful)
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jonnyboy
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Fri Nov 14, 2008 8:53 pm

when I saw the title I knew it was from you. :)
Nice idea with the epoxy. In the picture it looks weird kind of pale orange like pumpkin guts.
mobile chernobyl wrote:I can shoot a Canuter Valve off my '82 Chevy Ram F150 AT LEAST 3/4 Mile with 'ma cannon made of soup cans duct taped together, then I just squirt some bacardi 151 in the chamber and hold up my cigarrete lighta and WHOOSH! That thing flies at least 3/4 mile
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Fnord
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Fri Nov 14, 2008 8:55 pm

You need to put a nice spanish-to-engrish warning label on it.


Also, HA!
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VH_man
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Fri Nov 14, 2008 9:38 pm

Just one question... how does one Fuel/Vent this bugger?
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jackssmirkingrevenge
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Mon Nov 17, 2008 3:19 am

Qué combustible vas a usar dispararlo?
Just one question... how does one Fuel/Vent this bugger?
As indicated in the original post:
The second bolt is there to cover a port for fuelling (butane from a lighter refill canister metered with a syringe) and venting.
:wink: :P
_Fnord wrote:Also, HA!
And to think I was so careful! asshole :D

Can't wait to get back from work to try it out :)

edit: can't get the @#^$&!#$YU^%&#@%Q!!#@@#@!~!!! ignition to work reliably, damn epoxy and its permanent non-adjustable nature! Ah well, 'acksaw time...
hectmarr wrote:You have to make many weapons, because this field is long and short life
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SpudUke5
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Mon Nov 17, 2008 4:33 pm

jackssmirkingrevenge wrote:
Qué combustible vas a usar dispararlo?
Just one question... how does one Fuel/Vent this bugger?
As indicated in the original post:
The second bolt is there to cover a port for fuelling (butane from a lighter refill canister metered with a syringe) and venting.
:wink: :P
_Fnord wrote:Also, HA!
And to think I was so careful! asshole :D

Can't wait to get back from work to try it out :)

edit: can't get the @#^$&!#$YU^%&#@%Q!!#@@#@!~!!! ignition to
work reliably, damn epoxy and its permanent non-adjustable nature! Ah well, 'acksaw time...
Aww thats a shame. O well i guess, you'll get it goin eventually. How is the ignition hooked up?
4SPC, My 4" piston 3" porting cannon
Memo:
Fix up copper cannon
Fix up 4SPC
Start Stirrup pump
Start Toolies piston bazooka
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jackssmirkingrevenge
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Mon Nov 17, 2008 5:01 pm

something about the wiring of the piezo ignitor being too close and the spark is jumping somewhere else, I've taken one apart and JSRsalmorphisised it, hoping that epoxy is a good insulator we'll see what tomorrow brings :)
hectmarr wrote:You have to make many weapons, because this field is long and short life
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CasinoVanart
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Mon Nov 17, 2008 8:35 pm

Last planned project? Why not go back to the Hybrid Cartridges?
And whats this about not be able to get the ignition to work? Have you tried pressing the little button on top???? :D
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