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 73 users online :: 5 registered, 0 hidden and 68 guests


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

Registered users: 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

Injection Port

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

Injection Port

Unread postAuthor: vng21092 » Sun Dec 22, 2013 3:49 pm

Whats the best way of turning a hole that goes through 2 layers of pvc pipe into a fuel injection port? the hole is around 1/4 inch in diameter
For visual: http://imgur.com/wMbwDRx
  • 0


vng21092
Master Sergeant
Master Sergeant
 
Posts: 163
Joined: Tue Nov 19, 2013 8:27 pm
Country: United States (us)
Reputation: 6

Re: Injection Port

Unread postAuthor: PeteS » Sun Dec 22, 2013 3:57 pm

Drill it out with a an 11/32" or 23/64" drill bit and tap it for 1/4 pipe and then use whatever 1/4 pipe fittings suit you?
  • 0

My wife upon seeing my latest hybrid and hearing an explanation of it:
"That really isn't a potato cannon anymore, is it?"
User avatar
PeteS
Sergeant Major
Sergeant Major
 
Posts: 180
Joined: Wed Sep 11, 2013 5:53 pm
Location: Maryland
Country: United States (us)
Reputation: 12

Re: Injection Port

Unread postAuthor: vng21092 » Sun Dec 22, 2013 4:02 pm

hmm but how would i secure it?
  • 0


vng21092
Master Sergeant
Master Sergeant
 
Posts: 163
Joined: Tue Nov 19, 2013 8:27 pm
Country: United States (us)
Reputation: 6

Re: Injection Port

Unread postAuthor: PeteS » Sun Dec 22, 2013 4:42 pm

vng21092 wrote:hmm but how would i secure it?


Can you be more specific exactly what you are trying to do. Are you using a syringe? Trying to set up metered propane? something else? There are a ton of possible options for how to go with this.

If using a syringe, one way that has worked well for me is to use a presta valve (the skinny ones) from a bike inner tube and a 100 ml syringe with a presta to schrader adapter epoxied in. I solder or epoxy the presta valve into some kind of 1/4 pipe fitting. A cap with a hole drilled in it works as does a drilled out hose barb.

Image
Image
  • 0

My wife upon seeing my latest hybrid and hearing an explanation of it:
"That really isn't a potato cannon anymore, is it?"
User avatar
PeteS
Sergeant Major
Sergeant Major
 
Posts: 180
Joined: Wed Sep 11, 2013 5:53 pm
Location: Maryland
Country: United States (us)
Reputation: 12

Re: Injection Port

Unread postAuthor: jackssmirkingrevenge » Sun Dec 22, 2013 4:50 pm



I just use a small self-tapping wood screw for this one.
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 24225
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 66

Re: Injection Port

Unread postAuthor: vng21092 » Sun Dec 22, 2013 6:51 pm

The syringe thing was exactly what I was going for, thanks a lot. @JSR, would the wood screw ever pop out when firing?
  • 0


vng21092
Master Sergeant
Master Sergeant
 
Posts: 163
Joined: Tue Nov 19, 2013 8:27 pm
Country: United States (us)
Reputation: 6

Re: Injection Port

Unread postAuthor: jackssmirkingrevenge » Mon Dec 23, 2013 6:57 am

Let's do the math, say your wood screw is 1/4" in diameter, and the peak pressure of the combustion is 150 psi. The force on the screw at peak pressure would be around 7 lbs. Take a screw you want to use, tap it into a piece of PVC and hang a 10 lb weight from it. If it doesn't come off, you're pretty much golden. This is a worst case scenario, peak pressure will most likely be much lower and you can find smaller diameter screws.
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 24225
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 66

Re: Injection Port

Sponsored

Sponsor
 


Re: Injection Port

Unread postAuthor: jimmy101 » Mon Dec 23, 2013 4:21 pm

You can also use a standard tire stem (from a car tire). A rubber stem costs a buck or so, a nice metal one perhaps $2. Get a stem removal tool and permanently remove the stem and just close the port with the screw on cap. Tire Stems are installed from inside the chamber.

Image
center bttom is a rubber tire stem, its stem/core, cap and the removal tool.

Image
Shiny thing upper left of the chamber is a fancy chrome truck tire stem with a chrome cap.
  • 0

Image

jimmy101
Lieutenant General
Lieutenant General
 
Posts: 3127
Joined: Wed Mar 28, 2007 9:48 am
Location: Greenwood, Indiana
Country: United States (us)
Reputation: 7

Return to Combustion Cannon Discussion

Who is online

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

Reputation System ©'