A couple of (newbish?) questions

[Xalexalex]

Hello everyone!
I'm planning on building my first spud cannon. Wanting to do something more advanced than a plain spray-and-pray, I began to do some resarch on the fueling system and materials.

For practical reasons (weight and dimensions) I thought of a simple "valve" attached to the combustion chamber, to be used with a disposable butane cartriged like the following



In my mind I picture myself "pressing" this cartridge on the valve, which will open due to the pressure from the cartrige, letting the butane in. Much like when you refill a lighter, I guess.
My question is: does a valve like that exist? And if it does, will it substain the pressure from the inside, when the butane ignites?

As for the materials, I got interested in PVD-F (that is polyvinyldene-fluoride), which *in theory* is capable of sustaining greater pressures than PVC, PP or ABS plastics, but I couldn't find any practical info nor a direct experience on this.

I'll be glad if you could share your knowledge with me =)

All the best!
Alessandro

[Crna Legija]

The valve does exist you could take one from a camping stove that uses them cans, but it would be just like any other spray n pray cannon because you are not metering fuel into the chamber.

The pressure from a spray n pray is about 40-60psi more or less the same in a propane cylinder, so yeah if you can attach it the the cannon good it should hold the pressure.

[Xalexalex]

Any thoughts on the PVD-F idea?

[saefroch]

If you want to handle more pressure than pressure-rated PVC or ABS fittings can easily sustain, just use metal. There's no reason to be using plastic.

[Xalexalex]

Money, maybe?

[jackssmirkingrevenge]

Any thoughts on the PVD-F idea?

If it can take 100 psi without shattering, why not

As to fuelling, here's a self-explanatory thought:

[Xalexalex]

I like the idea, but I was looking for something... quicker to use. I'll check the home depot in a couple of days, see what I can find.

Btw, is there an introductions thread here? I couldn't find it anywhere =/

[mattyzip77]

[quote="Xalexalex"]I like the idea, but I was looking for something... quicker to use. I'll check the home depot in a couple of days, see what I can find.

Btw, is there an introductions thread here? I couldn't find it anywhere =/[/quote
Yes, I believe its called the "search" button, and the "wiki"!! Welcome to the forum!!

[jackssmirkingrevenge]

I like the idea, but I was looking for something... quicker to use. I'll check the home depot in a couple of days, see what I can find.

You can cut out the syringe, ball valve and check valve - but then you have no means of correctly dispensing the right amound of gas, so you've made a spray'n'pray.

Btw, is there an introductions thread here? I couldn't find it anywhere =/

You're in it

[Technician1002]

A simple syringe meter is not hard to make.

A piece of tube will do the job.

[ramses]

I like the idea, but I was looking for something... quicker to use. I'll check the home depot in a couple of days, see what I can find.

You can cut out the syringe, ball valve and check valve - but then you have no means of correctly dispensing the right amound of gas, so you've made a spray'n'pray.

Btw, is there an introductions thread here? I couldn't find it anywhere =/

You're in it

Use a 3 way valve and a meter pipe. If combined with a fan vent, 5-10 shots per minute should be do-able.

[Xalexalex]

I'll check the other threads to get some inspirations =)
Thank you all!

[jimmy101]

Following up on tech's post.

Other ways to do it;





all from the wiki http://www.spudfiles.com/spud_wiki/imag ... up_158.jpg

edit: and one not on the wiki:

editedit: btw, the last one is both a meter and an ignition system.

[Crna Legija]

I'll check the other threads to get some inspirations =)
Thank you all!

ahhh finally