It's been a while...

[STHORNE]

Hello fellow spudders! I know i have been out of the game for a while but i plan to return. Do to school, work and relationships, it has been hard to keep up with most of my leisurely activities. Unfortunately, spudding was one of them...

Now that i have my life under control (for the most part) i want to jump back into spudding. I miss the thrill i used to get when shooting my creations. After the recent death of my grandmother, i inherited enough money to pay off my student loans, a few car payments, and have a little spending money to splurge on whatever "trips my trigger" - spudding humor.

I've decided i want to make a party cannon. A couple days ago i had a graduation/birthday party and it was getting late/things were settling down. Nobody wanted to leave but things weren't as exciting as they should have been. I got the great idea of going to the local gas station to buy some fireworks! I hop in my truck, with a couple friends, drive 12 miles to find out the fireworks-half of the gas station was closed! Bummed, we drive back to my place wondering what we could do in the dark... then i remembered i had a (very) basic inline combustion in the basement. The only cannon left, as all of my others were sold to friends as i needed storage space. It ended up being a huge hit and people wanted me to make a better one for upcoming parties. Some even gave me money to go towards the project.

The most i plan to spend is $150 so i am somewhat limited to design ideas and materials. I do have leftover parts from other projects that could save me around $30-50.

My big question to you guys is... Combustion or Pneumatic?
I have some pretty good designs for both but my main concerns are:
*what would perform better for crowds?
*what would be more reliable/safe? -liability haha
*what would be most idiot-proof? (if somebody else wanted to shoot)

I could answer these myself but it's always good to get another opinion as i sometimes oversee certain pros/cons that could make for a better/worse decision.

Thanks guys,
STHORNE

[Technician1002]

For lability with crowds, the combustions are often considered a pyrotechnic and the proper permits and fire marshall approval is required. This is a show stopper for most home built combustions in public. The possibility of ejecting something on fire is a huge risk, so getting approval is very hard and is outright prohibited in most locations by insurance.

For safety it is recommended that the pressure be limited to under 100 PSI ( a legal requirement in some places ) and limited in size to limit the energy, this does not include a portable high pressure supply tank.

With air, limited pressure, and such you will find fewer roadblocks to using it in public. My little launcher was used at a concert to launch t shirts into the crowd.

Check my videos, others use my launchers. The ABS one is pressure tested every year and operated at reduced pressure in public. Due to the length and the way it it fired like a morter, most of the time the muzzle is above heads so the launch zone is relatively safe. It gets used every year at a church campout.

[blind909]

Welcome back STHORNE! Ive been out of the game lately too, and just now got back in the game!. And as for combustion or pneumatic, i HAVE to say pneumatics all the way! As for safety, i say pneumatic(as there is a risk of fire/firey explosion with combustion), and as for being idiot proof, i also say pneumatic, as a inexperienced spudder with an ignitor, fuel, and a pressure chamber(A.K.A. a combustion launcher) is NOT the greatest Idea.

[Technician1002]

Grr, I was looking up the rules for using home built shirt launchers in a professional sports arena. Unfortunately the link is broken, but the discussion remains. The wording had a small problem but it was sorted out to translate to no combustion.. This was for an engineering competion for T shirt launchers.

https://inteltrailblazerschallenge.wiki ... me/5438908

From the rules, please clarify: 5a "NO GAS POWERED ITEMS will be allowed in the Rose Garden Arena ("Arena")

Compressed air devices are allowed as long as they don't exceed 100 psi

Nitrogen, Carbon Diodide, or dry air in a regulated cylinder can be more than 100 psi for storage, like a paintball marker
the pressure is limitted to 100psi in the storage cylinder.

either bring a hand pump, cordless air pump, or a cylinder of compressed gas and a regulator.

[deathbyDWV]

Welcome back!!! I personally like pneumatics, but in this case I have to go for combustion. Think about if someone is going to shoot your pneumatic, and they drop it!!! BOOM!!! Shrapnel!!! (of course if the chamber ruptures) With a combustion, there's really no danger untill the trigger is pulled.

A combustion with c:b ratio to have short barrel (big flame/boom) would be crowd pleasing... Also consider clear chamber and barrel...

So I go with combustion, IF completely legal...

[SpudBlaster15]

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[blind909]

Also DeathbyDWV made a good point with pneumatics (about someone dropping it). To prevent that, make It an all metal gun, so it wont do jack shit if dropped.

[Gun Freak]

Making an all metal gun would be fairly expensive, at least for me...
I am a HUGE fan of pneumatics over combustions but in this case I would go with a metered propane advanced combustion for the reasons said already, also dropping a pneu could be bad...

[D_Hall]

When you say "crowd pleaser" I'm assuming you're just talking about "group of friends" and not actually a public venue/display as others in this thread have assumed. If so, most of their concerns become null and void.

IF so....

I'd go with an advanced combustion using transparent PVC, plexiglass, or a similar material for the combustion chamber and barrel. Heck, I'd even go simple combustion. I give the transparent combustion chamber/barrel more "gee whiz" factor than virutally any other feature you can come up with.

[STHORNE]

Wow! thanks guys.

I am hearing a lot of good with both.

@D_Hall-
Yes, i believe they miss understood me. I meant just for friends and family, i do not plan on revealing this to the public by any means. I am not sure on the legalities of potato cannons around here but i live out in the country so it doesn't really matter.

Although i am hearing a lot of good points with pneumatic, i am leaning towards combustion, just because of the BOOM factor. And when made with the correct pvc (pw) i don't see safety being an issue.

I am thinking Advanced Combustion unless somebody has a solid reason not to. And thanks to all of you for your constructive input

[Technician1002]

Advanced combustion is a crowd pleaser. It is high enough tech to be above a spray and pray, has good performance, and is portable without needing support equipment such as a compressor and electric power.

Don't overlook the lightweight ABS. In recent tesing, it looks to be a sturdy material and less likely to fail if it is dropped.

[STHORNE]

ABS would be an option but being in an area where only PVC is available, it isn't really an option, unless i am willing to pay extra to have it shipped; I am not.
PVC is all i have had to work with over the years. I feel more comfortable with PVC-PW because i know its limits where as ABS is foreign to me. ABS could be a better material but i don't think it would be an option for me.

In my mind i see ABS as the softer, more flexible material where as PVC is harder and more brittle. And if you wanted to bring a third factor into play, if i decide to do a Plexi-type material for the chamber for show, knowing if that would be safe or not bothers me too. I might have to order that one online lol

[Technician1002]

Plexiglass is very brittle. If possible use Polycarbonite instead such as Lexan. The clear PVC is a better option than plexiglass.

[starman]

Hey STHORNE, it has been a little while. Not sure if you were around for Trip Thunder a couple of years ago about this time. It is basically a combustion chamber and a 3" burst disk....really big noise!!! ...that a pneumatic just can't replicate. You can also attach barrels with the camlock sytem to shoot stuff if you so desire.

Oh I agree with D_Hall...go with a clear PVC chamber if you can swing it.

[STHORNE]

Yeah starman, it has been a while. Looking at your T-T i would like to build something similar to that. Never been much of a burst disk person though so i think that will be one think i won't include.

And as far as clear pvc goes, there is some clear material on launchpotatoes.com but i cannot tell what it is made from.