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Potato Cannon Barrel Too Short?

Posted: Mon Feb 16, 2009 11:17 pm
by GeekFreak
Well, first of all, i'm new here, so hello, hola, guten tag, and any other ways you can say hi. Second, this is my first combustion potato gun and I'm a little concerned about safety... I have a 3" wide by 8" long combustion chamber, and only a 12" barrel (at the moment). Would this be unsafe or would the potatoes not go anywhere because of the length? Any help is appreciated. Thanks!

Posted: Mon Feb 16, 2009 11:21 pm
by tape fist
you will have to increase your barrels size if you want better performance but it will still shoot just not that far.welcome to spudfiles

oh and i almost forgot,any chance on some pictures?

Posted: Mon Feb 16, 2009 11:22 pm
by trigun
Well I have to say welcome. I have to say that a 3" by 8" combustion chamber is roughly average. The best ratio is .8:1
With that being said... I need to know what size barrel you have not length. I'm guessing with that chamber volume that the barrel could probally be cut down a bit.

Posted: Mon Feb 16, 2009 11:22 pm
by GeekFreak
Thanks for the quick replies! Would it be possible to remove the barrel after using PVC cement to connect it to the fitting? I just want to try the gun out tomorrow and maybe buy more PVC in a couple days.

Posted: Mon Feb 16, 2009 11:24 pm
by tape fist
no you will have to find another fitting so that you may extend your barrel and i hope your using PVC primer to.

Posted: Mon Feb 16, 2009 11:25 pm
by trigun
what size is your barrel
Then cut it down and buy either a female or male adapter of that size and cement it on the stub so that it fits flush with chamber face. This will allow multiple barrels to be attached now also.

Posted: Mon Feb 16, 2009 11:27 pm
by roboman
Why don't you just try it? It's unlikely that it will blow up!

Posted: Mon Feb 16, 2009 11:27 pm
by GeekFreak
I didn't use primer (my friend said I didn't need to) but I did clean the pipe with some paint thinner, among other things. My barrel is 1.5" wide.

Posted: Mon Feb 16, 2009 11:28 pm
by trigun
Always use primer ( friends are usually wrong when it comes to building stuff that blows up ) It was smart to clean it however but primer is much more effective and safer

Posted: Mon Feb 16, 2009 11:30 pm
by GeekFreak
I'm going to have to shoot my friend with it now... Anyways, it would still be fine without primer as long as I cleaned it, right?

Posted: Mon Feb 16, 2009 11:33 pm
by tape fist
Dont say that its against forum rules to shoot any living thing. I know your joking but you still can get banned.

Posted: Mon Feb 16, 2009 11:33 pm
by trigun
Well with a small chamber yes it should hold together fine but for future notice use primer. Dont shoot your friend !! The moderators will kill you even if it is a joke. :shock: With the .8:1 ratio a two foot barrel is all you really will need.

I would cut your current barrel to about 2" long. Buy a 1.5" female adapter and prime and glue it on. Then buy the correct length barrel and put a 1.5" male adapter on it and your good to go

Posted: Mon Feb 16, 2009 11:35 pm
by GeekFreak
I guess I didn't read the rules, huh? Oops, I'm sorry.

Posted: Mon Feb 16, 2009 11:38 pm
by trigun
Well I didn't want to double post and edited but you posted before i could so see my above post

Posted: Mon Feb 16, 2009 11:41 pm
by GeekFreak
But I can just make the 12" barrel, and then cut it down and put the adapters + the right length barrel later, right? Oh ya, almost forgot, I'll post some pictures once I drill the hole for the sparker. I might spray paint it green, would that be cool or not?