Basic combustion design.. Looks okay?

[bigotry2]

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.

Any nice suggestions for making it look clean / sheek / awesome?

[Jumpin Jehosaphat]

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.

[sandman]

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

[MrCrowley]

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.

[bigotry2]

Well like I said they were left over pieces.

How to get propane in? Simple. Unscrew the cap and just stick the torch inside. 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.

[Jumpin Jehosaphat]

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.

[sandman]

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.

[bigotry2]

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.

[MrCrowley]

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.

[sandman]

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

[bigotry2]

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.

[sandman]

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

[Jumpin Jehosaphat]

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.

[sandman]

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

[bigotry2]

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??