tell me what u think

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.
nate_003
Private 2
Private 2
Posts: 29
Joined: Fri Feb 09, 2007 9:01 pm

Mon Mar 26, 2007 9:57 pm

i was looking at these the other day and thought hmmmmm maybe i can use this as a combustion chamber.......well i thought i would ask you guys what you think before i get alot of time and mony invested in it.

tell me what you think....




ps. its a 5 gal. water jug
Attachments
side shot
side shot
dcp_2187.jpg
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 26203
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 569 times
Been thanked: 344 times

Donating Members

Mon Mar 26, 2007 9:59 pm

That should take the 40-odd psi combustions produce... and in the event that it doesn't, it will rupture rather than shatter so no real danger from shrapnel either.
hectmarr wrote:You have to make many weapons, because this field is long and short life
nate_003
Private 2
Private 2
Posts: 29
Joined: Fri Feb 09, 2007 9:01 pm

Mon Mar 26, 2007 10:05 pm

i thought maybe use propane as a propellent......and maybe a 2" wide barrel.
User avatar
benstern
Corporal 5
Corporal 5
Posts: 908
Joined: Wed Sep 21, 2005 8:24 pm

Donating Members

Mon Mar 26, 2007 10:08 pm

It will rupture I can guarentee that. But i see it as a moderatly safe rupture.
User avatar
Fnord
First Sergeant 2
First Sergeant 2
Posts: 2239
Joined: Tue Feb 13, 2007 9:20 pm
Location: Pripyat
Been thanked: 1 time
Contact:

Mon Mar 26, 2007 10:15 pm

I think the mythbusters blew one of these up at above 60 psi, and it tore down the side. Just wrap it in ducttape and it should take the pressure.
User avatar
Velocity
Sergeant
Sergeant
Posts: 1039
Joined: Tue Feb 07, 2006 5:42 pm

Mon Mar 26, 2007 10:22 pm

_Fnord wrote:I think the mythbusters blew one of these up at above 60 psi, and it tore down the side. Just wrap it in ducttape and it should take the pressure.
Duct tape is not going to do anything. If their is enough force to split that plastic bottle, why would a few thin layers of relatively easy to rip (BY HAND!!) tape do anything at all?

Answer: They would not
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 26203
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 569 times
Been thanked: 344 times

Donating Members

Mon Mar 26, 2007 10:23 pm

_Fnord wrote:I think the mythbusters blew one of these up at above 60 psi, and it tore down the side. Just wrap it in ducttape and it should take the pressure.
There's a difference between the momentary pressure generated by combustion and the constant pressure in a pneumatic chamber, it should be fine even without the duct tape.
hectmarr wrote:You have to make many weapons, because this field is long and short life
From_Hamsterdam
Specialist
Specialist
Posts: 110
Joined: Thu Feb 15, 2007 8:26 pm

Mon Mar 26, 2007 10:28 pm

Water bottles are not designed to handle pressure. Coke bottles have to contain a pressured liquid(technically it's the gas) so they have to be able to handle pressure. Water bottles on the other hand only have to contain water so there is no need for them to be pressure rated. water bottles can handle a little bit of pressure, if they are left out in the sun the air/water will expand a little.

it is a big combustion chamber so it might reach high enough pressure to burst. also because it is short with a large diameter it will have a large flame front thus faster burning.

Even if there is only a rupture anything/anyone near it could receive bad burns.

if you do make it i would suggest firing it from a decent distance away and not holding on to the handle!
User avatar
MrCrowley
Moderator
Moderator
Posts: 10078
Joined: Fri Jun 23, 2006 10:42 pm
Location: Auckland, New Zealand
Been thanked: 3 times

Mon Mar 26, 2007 10:59 pm

Wrong section....read :evil: When you have made it into a gun feel free to post it here.
User avatar
Fnord
First Sergeant 2
First Sergeant 2
Posts: 2239
Joined: Tue Feb 13, 2007 9:20 pm
Location: Pripyat
Been thanked: 1 time
Contact:

Tue Mar 27, 2007 7:21 am

rmich732 wrote: Duct tape is not going to do anything. If their is enough force to split that plastic bottle, why would a few thin layers of relatively easy to rip (BY HAND!!) tape do anything at all?

Answer: They would not
I've tested a 2 liter bottle to 180 psi with a few layers of duct tape, and it didn't explode. There is a difference in the way enegy is exerted when youre tearing tape and when it is stretched by an expanding chamber. Try to rip it by pulling on the ends and see how easy it is. After looking at the bottle more closely I agree it wouldnt work as well because of the way the bottle is shaped compared to a normal round one.
nickz
Private 2
Private 2
Posts: 32
Joined: Mon Mar 26, 2007 2:30 pm

Tue Mar 27, 2007 1:37 pm

nate_003
Private 2
Private 2
Posts: 29
Joined: Fri Feb 09, 2007 9:01 pm

Wed Mar 28, 2007 10:45 pm


thankes nickz thats exactaly what i was looking for but wait... if theres going to be a pro ject tile in there the bottel will be under more preasure than whith out but i think it should be fine.
User avatar
A-98
Corporal 5
Corporal 5
Posts: 921
Joined: Thu Apr 27, 2006 7:41 pm
Location: Santa Barbara, CA

Wed Mar 28, 2007 10:54 pm

lol, i loved his look in the end *glance left, glance right* "nice"

i think it should work, and it will probably hold the pressure. however, i would suggest that you wrap it in chicken wire if you are concerned. if it survives the first 10 firings, it should live.
There are rules, and then there are hundred dollar bills.
User avatar
paaiyan
First Sergeant
First Sergeant
Posts: 2140
Joined: Wed Dec 27, 2006 10:03 pm
Location: Central Oklahoma
Been thanked: 1 time

Wed Mar 28, 2007 10:57 pm

rmich732 wrote:
_Fnord wrote:I think the mythbusters blew one of these up at above 60 psi, and it tore down the side. Just wrap it in ducttape and it should take the pressure.
Duct tape is not going to do anything. If their is enough force to split that plastic bottle, why would a few thin layers of relatively easy to rip (BY HAND!!) tape do anything at all?

Answer: They would not
You underestimate the power of duct tape in mass quantities. The stuff tears easily the way you're describing, but even pressure in a linear fashion will not so easily rupture the tape.
nate_003
Private 2
Private 2
Posts: 29
Joined: Fri Feb 09, 2007 9:01 pm

Wed Mar 28, 2007 11:08 pm

A-98 wrote:lol, i loved his look in the end *glance left, glance right* "nice"

i think it should work, and it will probably hold the pressure. however, i would suggest that you wrap it in chicken wire if you are concerned. if it survives the first 10 firings, it should live.

ya that look was like WOW!!!!!!!!!!!! :shock:
Post Reply