My new Spudgun!

[Kdogg]

I have recently made a new spudgun, The barrel is 2" & about 4 ft long, maybe a little less. It has a 3" chamber that is about 20in. long. I have implanted a lantern ignitor in the back of the gun, on the clean out plug. I fired it about 8 times with White Rain hairspray, the potato barely went 100 ft at the most & had as pussy ass shwoomp sound. The amount of hairspray in seconds spray varied from 2 to 7 seconds. Two to three seconds seemed to work the best. I then tried carb cleaner, thinking it was my hairspray that was bad, but that barely worked. WHAT THE HELL IS WRONG?? My friend has a small gun that is twice as loud when dry fired! Is my chamber too big or too small for my barrel? Do I need better propellants? Please help...


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Monkeyman

[ALENGOSVIG1]

You should've calculated the barrel/chamber length for optimum performance.

hairspray is a shitty fuel, don't use it. dont use carb cleaner either becuase it will deteriorate the the pipe. use propane, butane, or if you made the gun out of thick walled ABS pipe use MAPP/propane mix.


[This message has been edited by ALENGOSVIG1 (edited 12-01-2001).]

[Kdogg]

Shit, I dont know how to caculate to get the right ratios, nor have I seen any on sites. I have noticed that people that use 3" for the chamber & 2" for the barrel, use a shorter chamber, but damn near same length of barrel. So im thinking I will get another reducer cut the old one off, shorten the chamber, & try that. How do you disperse your propane into your gun?? & how much??


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Monkeyman

[BoB-]

Try switching to a smaller barell, as in 1 1/2", or 1". Keep reducing until you get optimum performance.

[CyclonitePyro]

My spudgun, is has a 4" y section, with a 5' long 1 1/2" barrel, I use static guard as the fuel, that stuff is just awesome, way better than starting fluid or propane. I have a 100,000 volt stun gun with wires leading inside the gun close to each other so when you push the trigger a large sparks jump across. Very loud, it makes your ears ring sometimes, and shoot potatoes across the lake I live at, maybe 250 yards.

If I want to post some pictures of it here would I take a picture with my digital camera and then put it on one of those picture hosting websites and post the url here?

O yeah, my first gun was exactly the one you described, it shot exactly as you desribed as well, it sucked.

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"Friends don't let friends play with
Nitrogen Triiodide"

[This message has been edited by CyclonitePyro (edited 12-02-2001).]

[Energy84]

Well, if you're like me, you're probably looking for the easiest possible fix. Try blowing air into the chamber after each shot. I might help a little bit...
Personally though, I prefer pneumatics. they're cleaner and more powerful in my opinion. I used the plans from this page: http://users2.nbn.net/~shindel/download_free_plans.htm and it's awesome! I made a few modifications to the diaphragm and used ABS instead of PVC to reduce the risk of the thing shattering in our cold Canadian winters! It performs very good too, launching a small, very hard frozen pear over 200yards at 40psi... no use using more pressure 'cause fruit isn't very aerodynamic and it slows down to terminal velocity right away :-( oh, it has a 1.5"x6' barrel and a 4"x4' chamber.

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why oh why didn't I take the blue pill?

[Kdogg]

I already have a pnuematic, uses a ball valve though. This one has interchangeable barrels.

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Monkeyman

[Kdogg]

Tonight I bought another 2 to 3in. reducer, & cut the old one off & shortened my chamber to 1 ft. It works pretty damn good now, & is just as loud as my friends when dry fired. Now I am more familiar with pnuematic ones, So I have a few more questions: 1.Sometimes when I use the hairspray It misfires & I need to clean it out or wait a while before it will work again. How can I fix this? 2.I am going to swich to propane, How much should I put in of this? 3 seconds? How to you put yours in, through a hole? Or from breech?

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Monkeyman

[CyclonitePyro]

I'm telling ya, use "Static Guard", it is in the laundry section of most stores, where the clothes detergents are.

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"Friends don't let friends play with
Nitrogen Triiodide"

[Kdogg]

Yeah, I have heard that before, but have not found it yet. Also today I bought some ether, & tried it. Not once did it fire. I think its because it shoots in a stream not in a mist. How much Ether would anyone reccomend?

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Monkeyman

[imported_Sgt_Starr]

Hey guys,

Wow long time no see eh?This upgrade looks nice...(just a little complicated for my taste) Anyways, more to the point. I have only gone through one spud gun(had some times when it has gone sour on me) Ive refurbed it and so on and it is still doing better than what yall say was your first combustion, (this was my first attempt and has out-tested models Ive have most recently made) My barrel is 33"X2" long with a 4 in flash supressor I made from a telescope Shade(it actually works well, it keeps my excess burn off or "flash" wich without the flash supressor is usually a 5 in diameter ball of flame into a 3 in long candle flame) My chamber is a 19"X3" PVC pipe, I use a Wal-mart brand Spray Lubricant(5 short bursts, mb 7) and I can fire a 1 1/2 Section of PVC pipe with a domed encap filled with paper and wrapped in Cardboard (tip is weighted with Elmers glue) about 300 yards, Sorry for all the blabble just to say that, its just really good to be back! (my ignition is a Grill Piezio connected to 2 Steel screws 1/2 in long spaced about 1/3 to a half in apart I usually get a spark under all conditions) I think the reason you have to wait awhile is because you have an excess of CO2 and water vapor in the chamber and not alot of O2 (ergo the no ignition or incomplete ignition) Try blowing in the pipe or using a bycicle pump to blow the CO2 out and the air in should work everytime then. hope this helps in someway!

[Fallout85]

CP- Yeah, it's great stuff. Surprisingly clean and powerful! Similar to straight butane. It makes a pretty good bang in my 1" barrell and 3" chamber gun. The first time I used it my neighbors thought it was a real gun and called the cops! I uploaded the jpg on the forum ftp so everyone will know what to look for.

[Fallout85]

RTC- Thanks. I didn't actually read NBK's message until after I had uploaded it. But I figured nobody would mind terribly since it's only 32k. I'll crop my photos from now on.

Yep, it's from a camcorder. I have this thing called Snappy that hooks the camera into the printer port essentially converting it into a digital camera. You can hook it into anything with the red and white prongs. VCR, TV, DVD, gaming consoles, ect. I got it on Ubid for about $30. It's normally about $60, but it's worth it.

[Azazel]

spudguns rule :D

[AcridSmoke]

I've made a couple of pneumatics and fired quite a few combustions, and I still like pneumatics.
I use the cheapest possible potatoes and a 1+1/4" barrel for two shots per big potato. The chamber is 1+1/2" by 5 feet. My friend uses a 2" barrel and a 4" by 4 feet chamber. (these are pneumatics). His barrel used to be much shorter, but now he uses a 7 foot barrel and I use a 10 foot. That changed the range for both of us from 250 yards to more like 400.
For combustion... My uncle's has a tiny chamber and a really long barrel. It shoots 300-350 yards with Aqua-Net Hairspray.

I suggest a 1+1/2" barrel with more length than your chamber, regardless of diameter. I've had the best result with a setup like this... Requires minimal measurement :)

[Zach]

if you dont have access to static-gaurd or whatever, try spray deoderant... check the fine print, it usually says what the propellant is. a friend of mine tried using oxy/acetaline... he had to get peices of pvc carved outta his face at the hospital :D

[Bignutsami]

How thick is everyone's spudgun PVC (in mm)?

Will help in comparing between countries which all seem to use different systems.

In Australia

PN18 40mm (1.5")= 4mm thick
PN18 50mm (2")= 5mm thick
PN18 100mm (4")= 9mm thick

Note - they are actually metric sizes, not imperial called metric, so slightly different sized to imperial systems.

[Anthony]

21.5mm (3/4") - 1.5mm
32mm (1.25") - 2mm
40mm (1.5") - 2mm
50mm (2") - 2mm
68mm (2.5") - 2mm
110mm (4.5") - 3-3.5mm

I haven't used 2.5" or 4.5" for pneumatic yet. Scarily thin huh?

[Sparky]

I've had some experience with spudguns. The only reason I don't like pnuematics is because 1)I don't have a good compressor and 2) they are not nearly as portable (I live in the city so I have to travel every time I want to use my SRDF). I put up a crappy page more than a a year or so ago and I don't think I have gotten a visitor since <img border="0" title="" alt="[Wink]" src="wink.gif" /> . It is basically a diary of all the stuff I have done since I started with spudguns: <a href="http://www.pyropage.50megs.com/." target="_blank">http://www.pyropage.50megs.com/.</a>
I run my gun with propane and I have devised a simple measuring device to make sure it works every time. Ether (QuickStart) does give a sharper bang if the amount is just right but it's just not worth the chance of getting it wrong, it not firing, airing out etc.I made it out of ABS because it was easier to get than PVC. I had lots of problems with fuel when I first started so that's why I decided to scrap the guesswork and go propane. My page has all the details about my three guns.
In Canada they usually refer to PVC pipe and ABS by schedule 20, 40 and so on but those are the common ones.

[AcridSmoke]

I've been using SCH40 pipe for all of my cannons... I believe my combustion friends have too. I don't know what the width is in mm, but it tends to have a 350 psi rating. That's more than enough for most spudguns.
My compression is usually around 90 psi. Unless you seriously damage the pipe, the only risk you have are improperly primed+cemented fittings.

[Spudgunner]

Just thought I'd put my new spudgun info up. Chamber 5 feet long, 4 inch pipe. The barrel is 10 feet long (right now, can be whatever length I want) and is whatever diameter I want ( I have a 2 inch female adapter on the chamber, can hook up whatever I want). It can be combustion OR pnuematic with a change of the endcap, and removing the sprinkler valve that is screwed onto the 2 inch female adapter. I need a new grill ignitor (or to modify the one I have so it will work), so I have not tested the combustion properties yet. I just finished the pnuematic converstion today though, and I have tested it. One word: "Wow!" I have a 10 foot, 1 inch barrel on there right now. I first tested it with a wad of newspaper at around 80 or 100 psi. I put a small (inch by 3 inch by 4 inch) paperboard box at the end of the barrel, held up by a steel plate a quarter inch thick, about 4 by 5 inches, and a hammer against that. I shot it, and pieces of newspaper went everywhere. It went through the box (obviously) and shot the steel plate and hammer back around 3 or 4 feet (on concrete).

Ok, so I decide it is time for a real test. I take a 2 liter bottle and fill it with water. I put a small (inch long hunk, if that large and inch diameter) in the barrel and set the barrel aimed at the 2 liter. Compress up to 100 psi and BAM! There is now a 1 inch hole in one side of the bottle with a split running vertically from the hole above and below it about 2 or 3 inches, and the cap is completely shattered from the hydraulic force. Not bad.... I am hoping to fully test the capabilites next time I head to my farm using a C-cell battery (perfect fit in 1 inch barrel). I am hoping for at LEAST a quarter mile range, and I am sure it will easily get that.

Spudgunner (aka Spudgunr)

[Purple Fire]

Ive only built one pneumatic spudgun before, just a real long ugly thin diameter prototype to test the principal, but im just starting work on my next one, a proper one. It will have a 65mm barrel that is split in two places with screw fitting so you can choose a long(accurate) barrel, a short( mortar style) one, or a compromise. There are 3 air tanks one to each side and one underneath. Two have valves at the end so you can have large, medium and small tank sizes. The barrel is 500mm long and each of the tanks is 300mm.
The only pipe available in NZ is either pressure pipe, or ordinary PVC spouting. While the pressure pipe is fairly cheap, the fittings are VERY expensive, otherwise i would have made several spud guns by now.
Pneumatic cannons are far better than crapy combustion ones, so much more reliable!
My fav ammo by far is ice slugs! you can get a perfect fit in the barrel and they are lubed from the water on the sides. They go for miles! The second favourite is fishing sinkers, i can get ones that fit perfectly in the 15mm barrel of the prototype and i can put one through a fence paling at 20m. For the new gun, i found that Monteith's beer botles fit almost perfectly in the barrel! im gonna be havin me some FUN!

[Yi]

Purple Fire..did you use to live in the UK? I think I know you :)
Send me an email if you did as I won't be here to read this until the end of this month..

[Ctrl_C]

I built a pneumatic one using the SGTC SupahValve. It's awesome. It will but a potato through 1" think Oriental Strand Board (similar to plywood) at over 50 yards. Caulking tubes fly straight as an arrow too. I've shot chains, bolts, nails etc., all make it through the board but the 8" long nails only go half way in. I also was shot with a foam ball (for soaking with water and throwing at people...a toy) at 20 feet at 50 psi and oh my god did it hurt like a mother. Like a giant paintball hitting you VERY hard. owwie. I am fully confident this thing could take out small aircraft if you could hit them and I am going to try to kill a deer with it.

[Cyclonite]

I would post a new thread but I dont have many posts and this is semi on subject.
I have entertained the idea of Sabot rounds for my spud gun for a while and decided to give it a shot. I used a foam cylinder cut in half surrounding the Sabot made of lead. I just drilled a 1/4 in sized hole in some wood and put in molten lead to make a sabot. I shapened the tip of the sabot and mushroomed the other end of it. I then placed it in the foam cylinder with duct tape on the rear ensureing even push on the projectile. Needless to say, I was rather impressed at the resullts of a sabot round from my spud gun (10') on a junked car, has anyone tried this before? Im sure there could be alot of improvment on this design.

[xyz]

I hope to do some experimentation with Sabot rounds in my Pneumatic Cannon. The cannon has two barrels, a 20mm one for launching small potatoes and CO2 cannisters, and a 50mm one for launching normal size potatoes, onions, etc. Both barrels are about 185cm long.

BTW, does anyone have a chart of what pressures different (Australian) PN classes are rated for?

I made mine from PN 9 which is about the same thickness as the stuff that Anthony mentioned earlier in this thread.

[Axt]

xyz, the PN rating is the pressure rating, PN9 means rated to 9bar. 9bar is 130psi.

[xyz]

I knew that it was the pressure rating, I didn't know what units it was measured in though. Thanks for telling me its measured in bar.

[Spaced Monkey 2002]

I recently tried a projectile made from a 6 inch section of the steel (?) rod used to reinforce concrete buildings. This was wrapped in masking tape to fit the 20 mm barrel of my friends pneumatic cannon. Sadly his compressor screwed up and we had to use a cheap-ass bike pump to pump up the cannon. It still managed to smash through a breeze block at 10 metres though. The breeze block was stood up against a wall for support...

[Flake2m]

I have a reletivly small pneumatic spudcannon. 25mm barrel and a 40mm air chamber both are about 1m long. I also have an attachable 15mm which I use for marbles. It is quite powerful for its size, especially at a fairly short range and at 100 psi.

I made a special sabot round for the cannon and I wanted to test it. I put a carboard box as a target. When I fired the round @ 120 psi the round made an entrance hole about 40mm wide and the exit hole was about 150mm wide :eek:. the round keep going until it hit a hardwood fence behind the box, at which point it embedded itself into the fence. It is stil there today.

The round I made consisted of 2 polystyrene blocks with an 10cm screw in the middle and 8 4cm nails surrounding it.

I have a "sniper style" piston spud cannon in the works, but progress has been delayed due to my studies. When I finally finish it though, the power it will have would be awsome.