Spudshot.com Hybrid build #1

[nicholai]

well i decided to get my foot outta my arse and start this hybrid project here, i did some work on the meter pipe, its currently all brass fittings except for the tee that threads into the pipe. its 8" long 1/4" diameter, the calculated chamber volume will be 125 cubic inches and the barrel length will be 72 inches, for a calculated chamber to barrel ( C:B ) ratio of about .8 to 1. Im also going with three pressure gauges (gotta add a tee to the middle of the meter pipe) one for the regulated tank pressure, one for the meter pipe (indicating proper pressure and no leakage after ball valve shutoff), and one on the end of the meter pipe to indicate tank pressure after the second meter pipe valve is shut off.

im going to go with a 1.5" barrel so i can shoot spuds and golf balls. i will probably sleeve the barrel (since its so long) and add some sort of sound suppressor to the end of the barrel.
The union is a sch 80. with a double o-ring on the inside and i plan on using polystyrene and polypropylene burst discs.
Im going to use sch-40 (im also hoping to burst it and catch it on film) with a dwv cleanout cap for testing purposes, dont worry im hooking up a 10 ft. remote ignition which i also plan on taking some pics of tonight
I plan on posting this prototype on my website (ill figure out the stand after i work the kinks out) as the first hybrid cannon i sell, if sch. 40 doesnt hold up to the test im going to go with sch -80.

the 80 mm fan (led of course) will be powered by a pair of rechargable 9v NI-MH batteries which i also use for my stun gun cannons. The switch will be a dimmer type so the speed will be adjustable (manual controlled ).

for ignition im going to go with a simple bbq clicker wired up to a four electrodes made of 10-32 threaded rod, since it will be a remote ignition ill make it detachable in case i want to swap in a stun gun ignition.

the stand will probably have to be made of 2 x 4s since it might be a little heavy, id love to use pvc but i want it to be sturdy and hold the recoil of such a powerful cannon.

heres a pic of the meter pipe, 150 lb hose with the barbs in em, propane bottle & pressure regulator. And now im off to cement the barrel and chamber together, ill keep ya posted, but for now heres a treat

[CS]

Please respect my opion and dont make a hybrid just yet. Look at me, ive been here alot longer and still havent finished a hybrid. Seriously you havent even been on here for a month! If you are indeed a fast learner a month is still not long enough. Also you dont use chamber fans in a hybrid, and a BBQ clicker wont cut it. Also golf balls dont fit in 1.5" pipe. Are you a idiot? Dont use a cleanout cap! Also dont risk it with a sch 40 construction. I can tell that you are excited and have sacrificed safty for time. Give it some time. Although you could build it and proably have a good working gun. Give your self some time before you take such a large step. I know this annoying always hearing the "hyrid rant", but were serious.

[spudshot]

please for the love of god, and for the safety of all who are thinking of ordering from you, DO NOT SELL HYBRIDS. unions on sch80 have exploded already, what if you sell it to some dumbass and he tries a 6x mix in it? you're gonna be 10 ft away from a sch40 hybrid with DWV cleanout? fuzzyscorpion's hybrid blew schrapnel 90ft away when his detonated, and it was sch80. http://www.msnusers.com/SpudGunnersElit ... PhotoID=18 a full sized sch80 cannon was there before, now thats all thats left in the gun mount

[Atlantis]

I agree with them. DON"T USE IT AS A HYBRID. If you adjust it a little bit, you could use it as a propane combustion cannon. I'm pretty that would be safe.

[beebs111]

i wouldn't reccomend sellin hybrids either 2 much liability for you, and what the hell are you thinking? i just had to say that because as everyone else already said, sch 40 is nowhere near safe for a hybrid and dwv, if you really must, i suggest you build a brick wall and extend that ignition to 30 ft

[PCGUY]

Take this somewhere else.

[boilingleadbath]

Oh boy...

Ok, those DWV endcaps have been known to fail in the common combustion. Don't be a retard... don't use them in a hybrid.

SCH 40 is generaly not reccomended for use in a hybrid. People generaly don't reccomend putting more than a 2x mix in them... if you feel you must do so, hide behind something sturdy.

I wouldn't reccomend selling hybrids to newbs. It's just not safe, in the same way you wouldn't trust a 9 year old to reload ammunition - the uneducated will probably, either intentionaly or accidentaly, charge it too high.

As to the chamber fan and BBQ sparker - they may or may not work. I'v heard that sparks don't travel very well in high pressure enviroments...

As a final thought, maybe it's a good thing that he's using a DWV cleanout. A rearward ejection is about the least dangerous failure I can think of for a hybrid... provided you arn't standing behind it!

[nicholai]

a simple combustion cannon is JUST AS ILLEGAL as a hybrid, the only difference is the chance of bursting the cannon. Combustion cannons (pressurized or not) fall under the same ATF jurisdiction.
I would most definatly ship low pressure burst with the hybrid cannon to eliminate an overpressurization hazard.
im not sure yet what ill actually do its just an idea thats why i posted it. the main idea behind this project is mostly to get a general idea of the burst strengh of pvc and to get video footage of why pvc cannons are not safe. im not trying to make extra sales off this site i just want to introduce my ideas and tests to further potato cannon technology. im not advertising or promoting my site through this forum, if i post something about a new cannon or idea its for education, not sales. I dont advertise for spudfiles.com or any other site as of yet so im not going to try to advertise on someone elses.
i also forgot to mention that ill be standing and recording behind a sheet of lexan (plexiglas) over ten feet away and im using the cleanout cap in hopes that the cap will blow before a fitting or chamber wall. The bbq clicker will be removable so i can test a stun gun as well.

as for the chamber fan i have no idea why i put that in there that is an idea i got with a propane launcher im building with the same C:B measurements, i got a kick ass plastic box and solid 9v clips/holders(also building a mini and 2 pnemuatics, musta mixed em up!)

Ive got acres of space for the test and ive blown up 4" pvc plenty of times before to know how not to get hurt. i think ill be all set with the experience and the knowelege of pressure and volume i have. Tomorrow ill post pics of the doomed chamber and barrel hookup tomorrow.

edit: what about the meter pipe and propane setup? should i gauge the spot between the ball valves or should i trust my regulator? think the endcap is gonna burst first?
i tapped the inside of the propane torch adapter so i could screw an elbow into it, this (sorta if the whole cannon is less than 180 deg. horizontal) prevents liquified propane from entering the hose. liquified propane doesnt ignite and the typical outside threaded, straighthrough design ive tried lets more liquid through when the cannon is totally horizontal, figured it try that out too for an idea (tapped out great 1/8" npt, no leaks)

[PCGUY]

Even thought that we know now that you don't intend to sell this cannon or advertise here, I still strongly suggest not selling them. It's a good way to put a bad image on the spudding community and get sued off your ass if one blows. Hybrids are just not predictable enough to give to the untrained person. Even if you make it as safe as you can, some dumbass will shoot it in the dead of winter even if you say to not shoot it in the cold and it will shatter and you're going to be in a world of shit.

[nicholai]

see thats what im totally paranoid of but i really want to offer a hybrid. maybe once i get a larger shop built ill buy a few extruder and injection molding machines and manufacture my own plastic pipe and fittings! that would be my long term goal, im two years short of an engineering degree in plastic molding so i know my way around plastic, maybe someday you'll be able to get 700 psi clear chamber pipe, with manufacturing markings cooler than the typical "LASKO PVC" or whatever brand you buy. possibility is endless, but then again im just rambling on and on...

i figure in a court case a person getting sued for selling spud guns (pressurized or not) is probably not going to be favored, and the higher chances of bursting are a big deterrant to trying to offer a prebuilt hybrid. chances are i wont offer it, but merely test it and record my progress here i dont ever want one of my cannons to blow up one someone, the chance alone of a simple combustion cannon exploding is a big risk to take