Login    Register
User Information
Username:
Password:
We are a free and open
community, all are welcome.
Click here to Register
Sponsored
Who is online

In total there are 55 users online :: 6 registered, 0 hidden and 49 guests


Most users ever online was 155 on Mon Aug 15, 2016 1:40 am

Registered users: anello, Bing [Bot], Google [Bot], Google Adsense [Bot], MSNbot Media, Yahoo [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

Basic combustion design.. Looks okay?

Post questions and info about combustion (flammable vapor) powered cannons here. This includes discussion about fuels, ratios, ignition systems, safety, and anything else relevant.
Sponsored 
  • Author
    Message

Basic combustion design.. Looks okay?

Unread postAuthor: bigotry2 » Thu Jul 05, 2007 7:21 pm

I bought some wrong PVC pipes when I was looking to build a pneumatic, too lazy to return them, so just making it into a semi-hybrid cannon. It's not set up to pressurize the propane, just the air, so at least I'll know it will shoot.

My purpose is just to have a very clean looking gun, with no dry wall screw for ignitor (I've already got it attatched into my T-joint thingy) it's just drilled straight into the pipe, sealed with epoxy putti and J-B Weld. The reason for the 45 degree elbow is ease of firing angled shots and I just though it looks hella cool. 8) Possibly considering putting a switch on the outside for the fan.. Possibly. The reason why I put it on the bottom extrusion is because propane sinks, thus the fan will blow the propane towards the sparker. :lol:

Any nice suggestions for making it look clean / sheek / awesome? :idea:
  • 0

Attachments
997-2.jpg

bigotry2
Private
Private
 
Posts: 22
Joined: Mon Jul 02, 2007 4:36 pm
Reputation: 0

Unread postAuthor: Jumpin Jehosaphat » Thu Jul 05, 2007 7:39 pm

That's a weird looking chamber... for combustion a plain cylinder would probably be best, but for pneumatic only I don't think the shape will affect flow that much. I'm not clear on how you are getting propane into the chamber. You should have the 9V battery outside of the chamber and you should use a switch of some sort.
4" pipe fittings are rarely pressure rated, If you don't have pressure rated PVC fittings you should reconsider you building materials. Non pressure ABS is ok because it won't shrapnel, but non pressure PVC is the worst of both worlds.
You need to be very careful if you plan on using this with any sort of hybrid mix. Remote detonation seems necessary, your asking for it with a shoulder fired PVC hybrid especially since the large diameter pipes are rated at low pressures.
  • 0

User avatar
Jumpin Jehosaphat
Sergeant Major
Sergeant Major
 
Posts: 188
Joined: Wed Jun 06, 2007 8:20 pm
Reputation: 0

Unread postAuthor: sandman » Thu Jul 05, 2007 7:40 pm

um, if you said that your using propane, where is the meter?
  • 0


sandman
Colonel
Colonel
 
Posts: 672
Joined: Thu Mar 15, 2007 6:59 pm
Reputation: 0

Unread postAuthor: MrCrowley » Thu Jul 05, 2007 7:42 pm

Ah I wouldn't use that for a hybrid or a pneumatic if you feel like living anytime soon. Thats a wye used for a chamber. They are not pressure rated, they are DWV and very thin. Do not use it as a chamber. Your whole chamber is DWV.
  • 0

User avatar
MrCrowley
Moderator
Moderator
 
Posts: 10207
Joined: Fri Jun 23, 2006 10:42 pm
Location: Auckland, New Zealand
Country: New Zealand (nz)
Reputation: 4

Unread postAuthor: bigotry2 » Thu Jul 05, 2007 7:46 pm

Well like I said they were left over pieces.

How to get propane in? Simple. Unscrew the cap and just stick the torch inside. :lol: Its extremely crude but thats how I've done it for a long time.

9V Battery on the inside to clean it up (like I said). Like I also said, thinking about a switch. If there will be no switch then what it will be is a 9V Battery holder with the clip on wire thingy where you just snap it to the top of the battery.

You are correct, these pipes are not pressure rated. Remember these are left over so these are going to be the ones I'm using. I won't be pumping the PSI very high at all (15 - 20 tops), which is why I put it in the combustion section and not hybrid section.

I will remote detonate it the first few times to make sure its safe. It's not shoulder fired, its hip fired, I'd NEVER hold somethign like this near my face when its ready to shoot. :lol:
  • 0

Last edited by bigotry2 on Thu Jul 05, 2007 7:50 pm, edited 1 time in total.

bigotry2
Private
Private
 
Posts: 22
Joined: Mon Jul 02, 2007 4:36 pm
Reputation: 0

Unread postAuthor: Jumpin Jehosaphat » Thu Jul 05, 2007 7:47 pm

His pipes may be pressure rated, but it isn't going to make a difference with the DWV fittings. You could possibly return/exchanges any parts you haven't glued or drilled so far and buy pressure rated stuff or ABS. Still if you are going to use this as a shoulder fired cannon, I wouldn't even recommend ABS. The best fittings have NSF-pw written on them somewhere.
  • 0

User avatar
Jumpin Jehosaphat
Sergeant Major
Sergeant Major
 
Posts: 188
Joined: Wed Jun 06, 2007 8:20 pm
Reputation: 0

Unread postAuthor: sandman » Thu Jul 05, 2007 7:50 pm

well, if you use DWV, your just making a wierd looking pipe bomb, so i would not build the rest of it, unless you can paint it really cool and show off the paint job and never fire it.
  • 0


sandman
Colonel
Colonel
 
Posts: 672
Joined: Thu Mar 15, 2007 6:59 pm
Reputation: 0

Sponsored

Sponsor
 


Unread postAuthor: bigotry2 » Thu Jul 05, 2007 7:54 pm

sandman wrote:well, if you use DWV, your just making a wierd looking pipe bomb, so i would not build the rest of it, unless you can paint it really cool and show off the paint job and never fire it.


I can live with that.. Where can I find some painting tutorials. :lol:
  • 0


bigotry2
Private
Private
 
Posts: 22
Joined: Mon Jul 02, 2007 4:36 pm
Reputation: 0

Unread postAuthor: MrCrowley » Thu Jul 05, 2007 7:57 pm

Well I think if you go ahead and build this hybrid with these DWV fittings it should be classed under this rule:

Discussion of solid propellants, explosive devices or incendiary projectiles fired specifically from a spud cannon is prohibited, and may result in a permanent banning of your account.For the purpose of this forum, these definitions will be used:
Solid propellant: Any substance containing all the chemical elements required to enable sustained combustion without the presence of additional oxidizers. This includes but is not limited to gunpowder, thermite, and many commercial and/or homemade pyrotechnic compounds.
For this purpose, nitroglycerine, though liquid, would qualify.
For this purpose, ordinary flour, though solid, would not qualify.
Explosive device: Any device that has the capability to release large amounts of stored energy rapidly.
Discussion of fireworks as projectiles is prohibited.
Discussion of "soda bottle bombs" or any other similar devices that may cause shrapnel as a result of uncontrolled rupture is prohibited.
Incendiary projectile: Any projectile that is capable of producing flame.
Rocket propelled projectiles, pyrotechnic smoke bombs, or any other burning projectiles would qualify as an incendiary projectile.


You shouldn't be building this for anything higher then a basic combustion, no propane.

And I know it says for explosive devices fired from a spudgun but there should be a rule for explosive devices that look like spudguns.
  • 0

Last edited by MrCrowley on Thu Jul 05, 2007 7:58 pm, edited 1 time in total.
User avatar
MrCrowley
Moderator
Moderator
 
Posts: 10207
Joined: Fri Jun 23, 2006 10:42 pm
Location: Auckland, New Zealand
Country: New Zealand (nz)
Reputation: 4

Unread postAuthor: sandman » Thu Jul 05, 2007 7:57 pm

well, i am not to good at painting, unless its MS paint, lol
  • 0


sandman
Colonel
Colonel
 
Posts: 672
Joined: Thu Mar 15, 2007 6:59 pm
Reputation: 0

Unread postAuthor: bigotry2 » Thu Jul 05, 2007 8:13 pm

MrCrowley wrote:Well I think if you go ahead and build this hybrid with these DWV fittings it should be classed under this rule:

You shouldn't be building this for anything higher then a basic combustion, no propane.

And I know it says for explosive devices fired from a spudgun but there should be a rule for explosive devices that look like spudguns.


No propane? I use propane on all my other combustions (made from ABS), and theres no tube-feeding system. Just unscrew the lid, stick the propane torch inside, count to 3 seconds, wave it around a bit, and put lid back on. I thought hybrid just meant pressurizing the propane and air inside the chamber, and combustion meant no pressurization.
  • 0


bigotry2
Private
Private
 
Posts: 22
Joined: Mon Jul 02, 2007 4:36 pm
Reputation: 0

Unread postAuthor: sandman » Thu Jul 05, 2007 8:18 pm

no, what you are explaining is a hybrid
i would explain bit im tired and im not a good explainer
  • 0


sandman
Colonel
Colonel
 
Posts: 672
Joined: Thu Mar 15, 2007 6:59 pm
Reputation: 0

Unread postAuthor: Jumpin Jehosaphat » Thu Jul 05, 2007 8:20 pm

The problem with this is that you are using unrated PVC. If it explodes you could be seriously hurt. ABS cannons are unrecommended, but will not kill you if they explode, just burn you a little.
  • 0

Image
User avatar
Jumpin Jehosaphat
Sergeant Major
Sergeant Major
 
Posts: 188
Joined: Wed Jun 06, 2007 8:20 pm
Reputation: 0

Unread postAuthor: sandman » Thu Jul 05, 2007 8:25 pm

like holding a giant granade in your hands
so i guess that it would not be much fun :roll:
  • 0


sandman
Colonel
Colonel
 
Posts: 672
Joined: Thu Mar 15, 2007 6:59 pm
Reputation: 0

Unread postAuthor: bigotry2 » Thu Jul 05, 2007 8:39 pm

So the general consensus is do not fire it.. That means I'm just gonna paint it to make it look really bad ass. But I'm still wondering if anyone knows of some paint tutorials??
  • 0


bigotry2
Private
Private
 
Posts: 22
Joined: Mon Jul 02, 2007 4:36 pm
Reputation: 0

Next

Return to Combustion Cannon Discussion

Who is online

Registered users: anello, Bing [Bot], Google [Bot], Google Adsense [Bot], MSNbot Media, Yahoo [Bot]

Reputation System ©'