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Stupid Spudcannon Website (Not Spudfiles)

A place to ask general spud cannon related questions.
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Unread postAuthor: spudlauncher » Fri Nov 02, 2007 1:52 am

my friend built one w/ a 1in. sprinkler valve, blowgun trigger, about the same size gun
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Unread postAuthor: psycix » Fri Nov 02, 2007 6:51 am

spudlauncher, you are the owner of the website aren you?

1- You are defending and supporting the website while most guys here think the opposite.
2- You have only posted in this thread.
3- You have joined just after this tread was going on!


Now please explain the unregulated CO2 to us.
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Unread postAuthor: Ragnarok » Fri Nov 02, 2007 7:27 am

@psycix: Sounds exactly like that to me.

Can I also add:

- A suspicious knowledge of the construction, and part names. And theories for why they are used.
- The fact that he knows that the endcaps have SCH 40 printed on them, despite the fact that the pictures on the site clearly show the Twister painted.
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Unread postAuthor: Fnord » Fri Nov 02, 2007 8:12 am

Where the hell is Kyle?
Time for some IP tracking :)

There are no DWV fittings on it. The ends of the fittings have sch. 40 printed on them.

Just because something says SCH40, it doesn't mean it is pressure rated!
Sch40 is a wall thickness, not a rating.
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Last edited by Fnord on Fri Nov 02, 2007 8:58 am, edited 1 time in total.
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Unread postAuthor: Ragnarok » Fri Nov 02, 2007 8:31 am

But, if you should happen to find SCH 40 Damascus steel* pipe then you can take it as read that it's tough.

* A legendarily strong steel used for making swords between the 12th and 18th centuries, recently discovered to contain carbon nanotube structures created by the complex production process
This post was brought to you by the Ragnarok foundation for the expansion of useless knowledge.
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Unread postAuthor: Fnord » Fri Nov 02, 2007 8:53 am

I always prefered to call it wootz :)

(edit: to those who have to ask, dont ask:)
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Unread postAuthor: benstern » Fri Nov 02, 2007 10:55 am

Yes, my original process of changing his contructuion tecqunices were to become progessivley worse.
1) my email
2) email from 10 spudders
3) call his home phone
4) email from 50 spudders
5) DDOS the site
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Unread postAuthor: spudlauncher » Fri Nov 02, 2007 11:33 am

My friend and I have been playing around in the garage for a few weeks now, coming up with ideas for guns and such. He watches spudfiles like a hawk for ideas and told me about this thread. It pissed me off because of how helpful they guys at cajuncannons have been. I emailed them last night about this thread. Someone apparently already told them a few days ago. Said he responded to every email last night. He forwarded me a copy. I'm surprised none of you have posted the email. Clears up most of the comments you've made. Here's what he sent in reply to a Kelly:

Kelly:

We've received a couple of emails from visitors to this thread, and are taking their concerns into consideration. Please understand that we would never use anything but Schedule 40 or Schedule 80 PVC. We use both, and nothing else. We request that a MAXIMUM of 80 psi is used in our pneumatic launchers. Scedule 40 is manufactured to handle pressures much greater than this, but for safety reasons we request 80 psi or lower. The instantaneous pressure that builds up within the chamber of a combustion cannon during that combustion is far greater than the 80 psi we use for the pneumatic launches. Not to mention, there are risks of unexpected combustion in between shots if there is an excess fuel lingering in the chamber. Pneumatic cannons are much easier to "play it safe" with. Of course, if guidelines aren't followed, a pneumatic cannon can be very dangerous. We provide safety instructions, and demand that they are followed. As long as everything is handled properly, our cannons are extremely safe. We've been in business for 5 years and have not had a single complaint of a cannon malfunctioning, exploding, or being unsafe. It's easy to look at the pictures on our site and assume that they are unsafe, but I cannot begin to explain how much care we put into each of our products. Each cannon is inspected before shipping. Each joint is sealed. Each hole we drill is reinforced. Every fitting we use is manufactured for pressurized conditions (Schedule 40 or higher).

We've been told that holes (such as for the pressure gauge) would be safer if drilled where a fitting overlaps the pipe. In theory, this makes sense, but only if the pressure gauge had a threaded surface that is deep enough to be screwed into the fitting and the pipe. But that's not the way they're built. If we installed a pressure gauge where a fitting overlapped the pipe, we would be drilling a hole through the fitting and the pipe, but the gauge would only be deep enough to break the inside surface of the cap. It would not break the inside surface of the pipe. Therefore, installing it at an overlap is by no means safer than installing it into a Schedule 40 cap.

The Simple Potato Gun is equipped with a piezo sparker, but is by no means "taped" to the cap. It is securely installed and causes no concern with regards to safety.

We use solid PVC pipe in the construction of all of our cannons, not cellular core pipe.

Our CO2 cannons have regulated remote coils, which are the same ones you find on a paintball gun. The safety valve on the CO2 cannons is just that...for safety. If our guidelines aren't followed, the CO2 cannon can be dangerous. The safety valve releases excess pressure to prevent an "explosion." The safety valve releases air at a rate of 40 scfm. The rate at which the regulator feeds CO2 at does not surpass that number. What makes the CO2 cannons so exciting is that projectiles can be launched at a more frequent rate. This is most useful in a T-Shirt Launcher. We've dealt with schools, churches, and businesses. We're yet to receive negative feedback.

I've noticed that people don't respect our stated launch distance for the Twister. Here's something to think about would you expect a gallon of air that's pressurized to 80 psi to provide more of a thrust when released through a 1" opening, or a 2" opening? The 2" opening, correct? The ball valve in the Twister is oiled, which allows for it to be twisted with ease. The 2" opening releases the pressurized air 4 times faster than the 1" irrigation valve used in our Electric Pneumatic. This is because the surface area of a circle with a 2" diameter is 4 times the size of the surface area of a circle with a 1" diameter. I must admit that we were surprized with the performance of the Twister, but we are definitely thrilled with it's power. I'm glad to see that one of our customers took it upon himself to attest to that. Like it or not, it is our most powerful cannon. Try building one for yourself...it's cost efficient, easy, and fun.

I truly appreciate your concern, and the concern of others who are posting on this thread. Please don't assume that we are using DWV fittings. Please don't assume that we're "taping" ignitors to guns. That is absurd. We would love to communicate back and forth with you guys...I'm sure we could learn a thing or two. We love "spudding" and we truly love the fact that we are able to call Cajun Cannons our own. Please feel free to post this message on the thread. It has also been forwarded to the other users who have contacted us.

Sincerely,
Steve
http://www.cajuncannons.com
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Unread postAuthor: spudlauncher » Fri Nov 02, 2007 11:35 am

oh...and I think we all know that a schedule 40 fitting has RAISED TEXT that shows the pressure rating. I said "printed" but i figured you'd know what I meant.
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Unread postAuthor: pyromaniac » Fri Nov 02, 2007 11:58 am

spudlauncher wrote:
Kelly:

We've received a couple of emails from visitors to this thread, and are taking their concerns into consideration. Please understand that we would never use anything but Schedule 40 or Schedule 80 PVC. We use both, and nothing else. We request that a MAXIMUM of 80 psi is used in our pneumatic launchers. Scedule 40 is manufactured to handle pressures much greater than this, but for safety reasons we request 80 psi or lower. The instantaneous pressure that builds up within the chamber of a combustion cannon during that combustion is far greater than the 80 psi we use for the pneumatic launches. Not to mention, there are risks of unexpected combustion in between shots if there is an excess fuel lingering in the chamber.


schedual doesnt matter it could be cell core. and also the pressure in combustions is normally less then 80 psi.
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Unread postAuthor: spudlauncher » Fri Nov 02, 2007 12:08 pm

Keep reading. everything you say is an assumption, not fact. those guys obviously aren't as dumb as you were hoping. is there really such thing as a 100% safe potato gun? HELL no. we all build and use them with the understanding that they can be dangerous.
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Unread postAuthor: williamfeldmann » Fri Nov 02, 2007 12:34 pm

I have a chunk of pipe sitting outside right now that says schedule 40 on it and is solid wall and it is not pressure rated. NOT PRESSURE RATED. Just because something is sch 40 doesn't mean squat without the rating.

Also, my first 10 or so cannons all used the union ball valves. I even spring loaded the last few based on directions found on spudfiles. My biggest was a four inch chamber dumping into a 1 1/2 inch barrel through a 2 inch ball valve and was nearly 10 feet long. It shot about 200 yards with beanbags that were much heavier and denser than taters. 250 yards = bullshit, not with those cannons and not at no 80 psi. I was using 150 psi.

Lastly, I have yet to see a pressure rated bell reducer. I have never seen a PVC, ABS, or Poly bell reducer that was rated in stores or even on the internet. You find me one, I'll believe, but until then bells are DWV and not safe even at 80.

The site is full of false ads and unsafe products.

EDIT: spelling (I will someday adapt to the spellcheck button :oops: )
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Last edited by williamfeldmann on Fri Nov 02, 2007 12:37 pm, edited 1 time in total.
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Unread postAuthor: jackssmirkingrevenge » Fri Nov 02, 2007 12:34 pm

It all sounds pretty reasonable to me, although the claim of firing 300+ yards with a ball-valved pneumatic does ring a little hollow, the conditions under which this figure was achieved (pressure, projectile type, distance measuring instrument etc.) would be appreciated.

One other small gripe, why do you sell those d!nky little portable compressors? Stop helping keep America obese, sell a decent strirrup pump instead :)
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Unread postAuthor: Fnord » Fri Nov 02, 2007 12:35 pm

I don't believe a person who randomly buys a cannon from a site would defend the site to the point you have.
If it were me, I would say yes, XXXX that was stated on the site is actually true, and If you don't believe it, well that's really your problem.

I would, of course, take flak for a statement like that, but that's when you have to offer some proof or stop talking. And, when you're up against a group as knowledgeable as this one, you'd better have some damn good proof.


Since I'm too lazy to send an email, I'll just answer this here.

Scedule 40 is manufactured to handle pressures much greater than this, but for safety reasons we request 80 psi or lower.


Wrong. As stated before, sch40 does not indicate a pressure rating.

The instantaneous pressure that builds up within the chamber of a combustion cannon during that combustion is far greater than the 80 psi we use for the pneumatic launches.


Wrong. Though it is possible in a textbook environment, pressures in an average gun don't exceed 80 due to heat loss from the chamber walls.
The exception may be a large gun with walls made of a very insulating material.

We've been told that holes (such as for the pressure gauge) would be safer if drilled where a fitting overlaps the pipe. In theory, this makes sense, but only if the pressure gauge had a threaded surface that is deep enough to be screwed into the fitting and the pipe.


Drilling into one layer creates a weak spot in the pvc. It's not an issue of the gauge popping out, as I believe that part is referring to.
Drilling through 2 layers is potentially safer because of the second layer giving extra strength to the first.

We use solid PVC pipe in the construction of all of our cannons, not cellular core pipe.


This is probably true. I'm still not so sure of the fittings, as even DWV fittings sometime use solidwall pvc. The difference in this case is DWV fittings are not subject to the quality standards that NSF-pw fittings are. Hence, they may have dangerous structural flaws.

The 2" opening releases the pressurized air 4 times faster than the 1" irrigation valve used in our Electric Pneumatic.


In a perfect world, yes, but I doubt you can open a ball valve in the same ~5 ms it take a sprinkler to open. In fact, a semi-light projectile will probably have left the barrel before you've even opened it halfway.

We love "spudding" and we truly love the fact that we are able to call Cajun Cannons our own.


You do not "love" spudding. You "love" making a buck from people who can't build things for themselves.
The ones who "love" spudding are the one who talk here and contribute to the advancement of the hobby.


On a sarcastic note,
We've dealt with schools, churches, and businesses. We're yet to receive negative feedback.


Anyone know why? :wink:
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Unread postAuthor: Ragnarok » Fri Nov 02, 2007 1:29 pm

I'm going to echo that comment - between all online spudders, we've seen everything and anything spudgun. (well, except a few things, but we're working on those.)

I can see _Fnord's already done it, but I'll break it down as well.

Complete inaccuracies in red, dangerous assumptions in orange, questionable information in yellow, true in green, good practise in blue, and unproven info in purple. My comments are in bold.

We've received a couple of emails from visitors to this thread, and are taking their concerns into consideration. Please understand that we would never use anything but Schedule 40 or Schedule 80 PVC. We use both, and nothing else. We request that a MAXIMUM of 80 psi is used in our pneumatic launchers. Scedule 40 is manufactured to handle pressures much greater than this, if it is marked as rated. Solid wall is not an indicator of a rating. but for safety reasons we request 80 psi or lower. The instantaneous pressure that builds up within the chamber of a combustion cannon during that combustion is far greater than the 80 psi we use for the pneumatic launches. Untrue, even with propane, pressure will not rise that high because of heat losses. Not to mention, there are risks of unexpected combustion in between shots if there is an excess fuel lingering in the chamber. Only with ignition, and fresh air. Pneumatic cannons are much easier to "play it safe" with. That is highly debatable. Combustion launchers never fire on their own. Pneumatics can fire with a leak in the pilot volume. Of course, if guidelines aren't followed, a pneumatic cannon can be very dangerous. Yes, but so can a combustion. We provide safety instructions, and demand that they are followed. Which will only work if the customer reads them. Demands aren't very impressive on paper (at least without, "we have your children" somewhere on the page.) As long as everything is handled properly, our cannons are extremely safe. We've been in business for 5 years and have not had a single complaint of a cannon malfunctioning, exploding, or being unsafe. It's easy to look at the pictures on our site and assume that they are unsafe, but I cannot begin to explain how much care we put into each of our products. Each cannon is inspected before shipping. Each joint is sealed. Each hole we drill is reinforced. You yourself admit that you don't! Every fitting we use is manufactured for pressurized conditions (Schedule 40 or higher). Again, Schedule 40 is not a rating. I could make a Schedule 40 bit of pipe from marshmallows, but would you use it? Much like lightyear is a distance (not a time), schedule 40 is a dimension (not a pressure rating)

We've been told that holes (such as for the pressure gauge) would be safer if drilled where a fitting overlaps the pipe. Completely and utterly true. In theory, this makes sense, but only if the pressure gauge had a threaded surface that is deep enough to be screwed into the fitting and the pipe. But that's not the way they're built. If we installed a pressure gauge where a fitting overlapped the pipe, we would be drilling a hole through the fitting and the pipe, but the gauge would only be deep enough to break the inside surface of the cap. It would not break the inside surface of the pipe. True, but there are greater concerns than the fitting forcing outwards. Therefore, installing it at an overlap is by no means safer than installing it into a Schedule 40 cap.

Holes drilled in the pipe are stress points. They are intrinsically more likely to fail. We're not talking just about the fitting blowing out, but also the pipe failing. A hole like that, particularly a threaded one, is a prime location for a crack to start. Cracks are seriously bad. They increase stress concentrations, and increase the risk of failure many times over.
In a double thick layer, a crack is less serious, and less likely to be above the critical length.


The Simple Potato Gun is equipped with a piezo sparker, but is by no means "taped" to the cap. It is securely installed and causes no concern with regards to safety. Need I say more than Frogboy?

We use solid PVC pipe in the construction of all of our cannons, not cellular core pipe. Better than using cell core, but using rated would be better.

Our CO2 cannons have regulated remote coils, which are the same ones you find on a paintball gun. The safety valve on the CO2 cannons is just that...for safety. If our guidelines aren't followed, the CO2 cannon can be dangerous. The safety valve releases excess pressure to prevent an "explosion." The safety valve releases air at a rate of 40 scfm. The rate at which the regulator feeds CO2 at does not surpass that number.We're yet to receive negative feedback.
That's probably because most people don't know better. And this whole topic sounds negative to me.

CO2 cools on depressurization. If you run CO2 through the chamber at anything near that rate, it will cool, becoming brittle. Not to mention you are spewing large amounts of a gas harmful to humans in high concentrations about.

I've noticed that people don't respect our stated launch distance for the Twister. Here's something to think about would you expect a gallon of air that's pressurized to 80 psi to provide more of a thrust when released through a 1" opening, or a 2" opening? The 2" opening, correct? Yes, if the opening times are similar. The ball valve in the Twister is oiled, which allows for it to be twisted with ease. The 2" opening releases the pressurized air 4 times faster than the 1" irrigation valve used in our Electric Pneumatic. Faster actually, but only when fully open, and short of having super speed, that ain't happening while the projectile is still in the barrel.

I must admit that we were surprised with the performance of the Twister, but we are definitely thrilled with it's power. I'm glad to see that one of our customers took it upon himself to attest to that. Like it or not, it is our most powerful cannon. I can smell male bovine excrement. Try building one for yourself...it's cost efficient, easy, and fun.

Probably true, but most spudguns are fun. And why should I need to? I already have something a quarter of the size that's just as powerful.
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