Got some question about Supercannon ll

Build a homemade water gun or water balloon launcher and tell us about it.
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Chekist
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Got some question about Supercannon ll

Post by Chekist » Sat Jul 05, 2008 4:17 pm

Hello everybody!
I want to make supercannon by myself so i create this topic.
I have 1 question for now - i found only 1 type of reducer (9102K243 on http://www.mcmaster.com/) but it can't be used under pressure... so may i use them to make this cannon? (i'm from russia, sorry about my bad english then) or i should choose another one?
Last edited by Chekist on Sat Jul 05, 2008 4:37 pm, edited 1 time in total.

aEx155
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Re: Got some question about Supercannon ll

Post by aEx155 » Sat Jul 05, 2008 4:41 pm

Welcome to the forums!

Looking at the part, it says that it cannot be used under pressure; doing so would leave a high chance for failure and you could probably injure yourself.

Given some time, I could get a list of parts for you to try, but I'm kinda busy right now.

It would help if we knew what you were working with in Russia; I can tell that you can order from Mc-Master Carr, but do you have access to hardware/plumbing stores in your area? I'm not sure of any international supplier, but I'm sure Ben could help with that.

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Chekist
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Re: Got some question about Supercannon ll

Post by Chekist » Sat Jul 05, 2008 4:53 pm

aEx155 wrote:Welcome to the forums!

Looking at the part, it says that it cannot be used under pressure; doing so would leave a high chance for failure and you could probably injure yourself.

Given some time, I could get a list of parts for you to try, but I'm kinda busy right now.

It would help if we knew what you were working with in Russia; I can tell that you can order from Mc-Master Carr, but do you have access to hardware/plumbing stores in your area? I'm not sure of any international supplier, but I'm sure Ben could help with that.
OMG :) It will be great!!! It's rly hard to find some of parts in our city. I spent about 7 hours today trying find some of them, but unsucsesfull.. i'll try to get materials from Mc-Master Carr, but it will be much faster if u'll get a list of parts (with links to Mc-Master Carr), so i can see parameters of this part. Thanx again!!!

aEx155
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Re: Got some question about Supercannon ll

Post by aEx155 » Sat Jul 05, 2008 5:24 pm

From what you said, it seems like you're very limited on supplies; I've never been to Russia, so I don't know what it's like. It seems like you're going to be doing a lot of ordering for this project.

Well, looking at Ben's other thread about his CP45Ewing Irrigation, which is a supplier of pressure rated fittings. I'm not sure whether or not you could order from them, though. You could always try a package forwarding service, if you need to.

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Silence
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Re: Got some question about Supercannon ll

Post by Silence » Sat Jul 05, 2008 5:31 pm

Your English is as good as most native speakers' English. Don't worry. :)

Ordering from McMaster-Carr may not be practical because shipping PVC pipe is expensive. If you can find pipe in your town, that would be a very good first step. Otherwise, try looking for copper or whatever material plumbers use in buildings there.

Sorry for the lack of options...but the best course of action is usually to use whatever material is most available.

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cantab
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Re: Got some question about Supercannon ll

Post by cantab » Sat Jul 05, 2008 8:11 pm

Copper's good for most guns, if a bit heavy. But doesn't the performance of SCII depend on having a large diameter pressure chamber? Copper usually only goes up to 28mm.

Also, have you made any air-pressure weaponry before? If not, I wouldn't suggest SCII as a first project. A simpler air pressure homemade will be easier; they can be done with copper pipe and a soda/pop/fizzy drinks bottle as a pressure chamber, and while you won't get 70 feet you should have no trouble getting 50.

aEx155
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Re: Got some question about Supercannon ll

Post by aEx155 » Sat Jul 05, 2008 8:55 pm

cantab wrote:Copper's good for most guns, if a bit heavy. But doesn't the performance of SCII depend on having a large diameter pressure chamber? Copper usually only goes up to 28mm.

Also, have you made any air-pressure weaponry before? If not, I wouldn't suggest SCII as a first project. A simpler air pressure homemade will be easier; they can be done with copper pipe and a soda/pop/fizzy drinks bottle as a pressure chamber, and while you won't get 70 feet you should have no trouble getting 50.
The performance of the Supercannon II is based on how it is designed. High flow ball valve, piston-based PC, and a conical nozzle was what helped it reach such range and output. If you make a "mini-supercannon" out of all 28mm pipe, I believe you could get the same performance, just smaller since the gun it smaller.

cantab is right about starting with something simpler. Even though the Supercannon II looks simpler because it doesn't have a pump, it's a lot harder to use than a regular gun like a n APH. If this is your first gun, I would suggest doing that instead; you can try the Supercannon again when you've gotten some experience with building water guns.

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SSCBen
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Re: Got some question about Supercannon ll

Post by SSCBen » Sat Jul 05, 2008 9:40 pm

In the guide I did not use pressure rated reducers. At the time I wasn't aware that my reducers were not pressure rated. All other fittings are pressure rated. I can't suggest a similar practice but nothing bad should happen if you don't use pressure rated reducers and reasonable pressures.

I'm also unsure whether McMaster-Carr ships to Russia too. From what I've seen they generally only ship to the US. I'd suggest looking for a similar service in Russia or Europe because you will have to pay a huge premium for shipping from the US anyway. I probably should have mentioned this in my email to you.

In my new CP45 water gun mentioned earlier I am using a pressure rated bushing and coupler as opposed to a bell reducer. Bell reducers are not made pressure rated in 4 inch sizes so I had to get the next best thing.
Copper's good for most guns, if a bit heavy. But doesn't the performance of SCII depend on having a large diameter pressure chamber? Copper usually only goes up to 28mm.
If you want any reasonable amount of water volume, yes, larger diameter pipe is necessary. 28 mm is definitely too small.

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Drenchenator
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Re: Got some question about Supercannon ll

Post by Drenchenator » Sun Jul 06, 2008 1:42 am

Welcome to SSC, Chekist!

Ordering pipe on McMaster even in the states is very expensive. If you've already check locally, I guess it's your only choice, but be warned that it's not going to be cheap.
cantab wrote:Copper's good for most guns, if a bit heavy. But doesn't the performance of SCII depend on having a large diameter pressure chamber? Copper usually only goes up to 28mm.
aEx155 wrote:The performance of the Supercannon II is based on how it is designed. High flow ball valve, piston-based PC, and a conical nozzle was what helped it reach such range and output. If you make a "mini-supercannon" out of all 28mm pipe, I believe you could get the same performance, just smaller since the gun it smaller.
The higher diameter doesn't directly help performance, but it definitely doesn't hurt. Larger diameter pipes allow more flow; and consequently more laminar flow. It's no mistake that SCII got 73 feet at 135 oz/sec--the high flow rate helped a lot. The idea is that by creating a lot of flow, you have a better chance of having more laminar flow if the design allows it. The greater the flow rate, the more of a "laminar flow rate" you have. Plus, larger diameters don't exactly hurt water capacity.
The Drenchenator, also known as Lt. Col. Drench.

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Chekist
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Re: Got some question about Supercannon ll

Post by Chekist » Sun Jul 06, 2008 3:48 am

Thanx all for answer! About building big guns w/o experience - all Russians like a big guns/weapons as u know (or don't :) ), and i'm shure that i can made it, just need some parts and time. As for McMaster... i ask them and waiting for answer about delivery to russia. At this moment i trying to draw some pictures of Supercannon ll in Visio with a list of parts, length, high.... I'll send it to Ben then i finish (if u need it ofc). I hope It will be little easy to others to make Supercanon ll with this picture.

I found only one type of pipe with d=4,331" (PPRC type). :(
Have problem to find Piston Cup (Buna-N piston) as well... anybody know where it use for?

And i found some Piston Cup... is it made from polyurethane resin?
Last edited by Chekist on Sun Jul 06, 2008 11:59 am, edited 1 time in total.

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SSCBen
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Re: Got some question about Supercannon ll

Post by SSCBen » Sun Jul 06, 2008 4:46 pm

Piston cups are used in a variety of things. Any large industrial supply store should carry them. Look for something similar to McMaster-Carr in Russia. I am sure it exists.

The material the piston cup is made from largely doesn't matter as long as it seals. The ones I have are made from Buna-N rubber.

It might be easiest for you to make a piston with an O-ring seal instead of piston cups. O-rings are much easier to find. ;)

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Chekist
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Re: Got some question about Supercannon ll

Post by Chekist » Mon Jul 07, 2008 10:41 am

Found ALL parts (i mean pipes, reducers, not pistons yet :( ) pressure rated (about 150 psi) but they made from polythene. Is it good to use with vaseline? And anybody know where i can see that (compatible or not)?

As for redurers and pipe... got pipe about 5 feet length, d=4 inch, reducers are 4 inch to 2 inch (i think to use ball valve 2 inch too).
Last edited by Chekist on Mon Jul 07, 2008 11:10 am, edited 1 time in total.

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SSCBen
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Re: Got some question about Supercannon ll

Post by SSCBen » Mon Jul 07, 2008 11:22 am

I can't find any information about polyethylene's compatibility with vaseline (petroleum jelly) or some other common lubricants. I'd imagine there isn't a problem. When you get the pipe and fittings, if you have an extra fitting smear some vaseline on it and see if there's any reaction. If vaseline reacts with it try something different like a silicon based lubricant.

Edit: Just noticed something on McMaster-Carr. Many fittings don't have a pressure rating, but are NSF rated. Check the NSF rating. If it's NSF-61 or NSF-PW you're good. If it's NSF-DWV avoid that fitting.

This means that I could have used McMaster-Carr fittings in CP45 because they have what I want NSF-61 rated. I guess Ewing isn't necessary then.
Last edited by SSCBen on Mon Jul 07, 2008 2:24 pm, edited 1 time in total.

aEx155
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Re: Got some question about Supercannon ll

Post by aEx155 » Mon Jul 07, 2008 3:44 pm

Chekist wrote:Found ALL parts (i mean pipes, reducers, not pistons yet :( ) pressure rated (about 150 psi) but they made from polythene. Is it good to use with Vaseline? And anybody know where i can see that (compatible or not)?

As for reducers and pipe... got pipe about 5 feet length, d=4 inch, reducers are 4 inch to 2 inch (i think to use ball valve 2 inch too).
One thing I'd change is the 2" ball valve; the size makes it very hard to turn. I've tried turning most sizes of ball valves and the force the large ones take is a bit outrageous. I would go with something more reasonable, like 1 1/2", or get some lubricant, if possible.

Where did you find your parts? It would be interesting to know and it might be helpful if we have anyone else drop by here.

I'm sure Vaseline would work fine for polyethylene; o be sure, just try what Ben said so that you don't end up damaging anything.

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Silence
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Re: Got some question about Supercannon ll

Post by Silence » Tue Jul 08, 2008 3:52 am

As long as you can easily replace the seals, Vaseline should be fine. Oil-based lubricants damage natural rubber over time, but even that takes a while; I'm sure synthetics don't have a problem.

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