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Total noob needs advice on the next step.

Post questions and info about pneumatic (compressed gas) powered cannons here. This includes discussion about valves, pipe types, compressors, alternate gas setups, and anything else relevant.
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Unread postAuthor: jackssmirkingrevenge » Tue Jan 12, 2010 11:26 pm

bullrees wrote:What is a realistic time for a ball valve 500ms ?


It's highly subjective, it's really down to ball valve friction and the individual opening it. 500ms is probably a reasonable guesstimate.

My main objective with GGDT for now is to simulate what I have(this spud gun) so I can tweak it and see the results.


Now that you've been bitten by the bug, your main objective now should be getting your hands on a better valve ;) or if you fancy a bit of craftwork, how about spring loading the ball valve.

Image
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Unread postAuthor: bullrees » Wed Jan 13, 2010 5:06 pm

Yeah I definitely need a better valve. I've been looking at many of the guns on the forum to see what works best in different types of designs.

Also I was talking about this with some guys at work today because one of them has a welder and I asked if he would mind doing some welding if I needed. Anyway it turns out a few of them already knew of this website and were also very interested.It looks like I have a small team of fellow nerds to help out. :D

EDIT:almost forgot. It's hard to see in the pick put is that a spring with a cable to the valve handle that yanks open the valve?
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Unread postAuthor: MrCrowley » Wed Jan 13, 2010 5:16 pm

EDIT:almost forgot. It's hard to see in the pick put is that a spring with a cable to the valve handle that yanks open the valve?

Yeah. Sometimes the spring is directly connected to the valve but in this case the builder uses a piece of wire or so which pulls the valve open when the spring is released and yanks the wire back.

Interesting that people at your work know of this site, I guess none of them are regular members then.

Do you have any ideas for your next build? If you have acess to a welder and possibly machining tools like a lathe or such, you could always build something like a QDV cannon, see this thread:
http://www.spudfiles.com/forums/quick-d ... 17858.html
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Unread postAuthor: bullrees » Wed Jan 13, 2010 6:42 pm

Wow that is awesome...I don't have machining tools but he did say he turned the 2 inch with a drill press so that may be doable.(wonders if the wife will let me buy a lathe just for spud guns)

I'm not sure about what to build yet. Every time I look at the guns on here I say "I WANT THAT" to myself lol.

If I have some people to help with the work and the cost, I'm leaning toward something large and ridiculous. The area that I live in is not very open and the lot my house is on is only about 5k sq feet so there's a good chance of a projectile ending up in my neighbors dining room. I'd have to find a nearby field or something so portability could be a concern.

If the "team" interest is not that great I'll start with something smaller but has good components.

The first thing I'm gonna do this weekend is fix the one I have. My son likes it and it's easy for him to use. I'll just find the correct reducer, cut off the old and put in the new. Or better yet grab a sprinkler valve also and see what kind of hurting we can put on some spuds like that and let him have that gun. I only do it for the kids...lol :roll:
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Unread postAuthor: Techie » Wed Jan 13, 2010 7:06 pm

kjjohn wrote:First off, get rid of all that duct tape! You did use PVC glue didn't you?

Another thing you could do is make the barrel somewhat longer (longer barrel=more time for gases to accelerate the spud), and use a sprinkler valve instead a ball valve. Have a look at some of the other sprinkler valve guns on the forum to give you some insight. A sprinkler valve can provide I believe up to 50% more power due to the faster opening time, especially if you mod it to run pneumatically with a blowgun. Look up sprinkler valves on the Spudwiki as well.

In terms of the pressure gauge, you could either attach it with fittings, or you could drill and tap a hole in the side of the chamber for it. This involves buying thread taps, however, which can get pricey. I would just order some fittings or go somewhere else to get them.

Welcome to Spudfiles. :)

Why would you bother removing the duct tape? its doing no harm and it may hold some pieces of shrapnel back if it explodes

I hope my last sentence hasn't discouraged you from spudding =P
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Unread postAuthor: MrCrowley » Wed Jan 13, 2010 7:09 pm

Why would you bother removing the duct tape? its doing no harm and it may hold some pieces of shrapnel back if it explodes

If you have to put duct tape on your cannon 'just in case', then I wouldn't be using the cannon in the first place. I would say it is more likely that the bell reducer will fly off rather than explode. DWV fittings have short socket depths.
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Unread postAuthor: bullrees » Wed Jan 13, 2010 7:55 pm

The main reason I removed it was to look at the fitting better to be sure it was not pressure rated. The wiki page showed a bell type reducer that was rated so I didn't know what I had.

I put the tape on for the same reasons Techie said and a warning I read that said "pvc does not show up on xrays". I'm not sure if pvc shows on xrays or not but the thought of a doctor fishing around in my arm for some pvc was enough for me to put it on.

A substandard fitting was enough for me to take it off and do it right. Kids seem to love this stuff so a bell fitting flying off into a 5 year olds head is not something I want.


EDIT:What about aluminum? I'm eying the two D cell maglite flashlights I have with bad intentions. Mainly because they have threaded caps with o-rings and a hole through the main body for the on/off switch.
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Unread postAuthor: jackssmirkingrevenge » Thu Jan 14, 2010 12:40 am

bullrees wrote:I put the tape on for the same reasons Techie said and a warning I read that said "pvc does not show up on xrays". I'm not sure if pvc shows on xrays or not but the thought of a doctor fishing around in my arm for some pvc was enough for me to put it on.


Turns out that's a load of bollocks ;)

What about aluminum? I'm eying the two D cell maglite flashlights I have with bad intentions. Mainly because they have threaded caps with o-rings and a hole through the main body for the on/off switch


The already do maglites in 0.410:

[youtube]http://www.youtube.com/watch?v=euoy_yN3uEE[/youtube]

You could conceivably scale up the marker pen designto fit in the maglite and have yourself a powerful little 1/2" or 3/4" high pressure piston cannon ;)
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Unread postAuthor: bullrees » Thu Jan 14, 2010 8:39 pm

I'm interested to know if anyone has made a coax but instead of just a dump valve... used the venturi effect during filling to create a vacuum in a smaller separate chamber to help "suck" back a piston in addition to the chamber pressure.
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Unread postAuthor: bullrees » Fri Jan 15, 2010 10:38 pm

Sorry for the double post but went shopping today.

The bad news is the home depot I went to didn't have any pressure rated fittings bigger than 1.5 inch.

The good news is they had the 1 inch rainbird CP-100's. So I picked up two of them and a basic tap/die set. I also got 10 feet of 1 inch and ten feet of 1.5 inch sch 40 pressure rated pvc pipe.

This pic is the basic layout for two over under guns without the tubes in order from barrel to chamber.
1 inch barrel(not in pic)
1 inch screw in fitting
1 inch rain bird cp-100 valve
1 inch screw in elbow
1 inch tube(not in pic)
1 inch to 1.5 inch adapter inside a 1.5 inch elbow
1.5 inch chamber(not in pic)
1.5 inch end cap.



Image

I'm not familiar with the screw in fittings and would like to be sure they are good to use. I took some pics as close as I could.

The barrel 1 inch screw in fitting on the output of the valve.


Image

The 1 inch screw in elbow fitting on the input of the valve.
( it looks like it has a crack in it but it is just a shadow from the flash)
Image

After all this..the biggest tap is not big enough for the pressure gauge threads so I'll have to go back and get some adapters. I also plan to pick up some mod parts for the cp-100's so i can use them blowgun actuated instead of electric.
I'm not set on two guns...just got two sets because the 1inch valves are hard to get here. Ideas for one gun with two valves are very welcome
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Unread postAuthor: jackssmirkingrevenge » Sat Jan 16, 2010 2:02 am

bullrees wrote:Ideas for one gun with two valves are very welcome


There's quite a few dual valved cannons for inspiration if you look around the pneumatic cannon showcase, like this one.
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Unread postAuthor: jhalek90 » Sun Jan 17, 2010 11:41 am

I like the duct tape?? or not... idk... i can never decide with duct tape. hahaha
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Unread postAuthor: bullrees » Mon Jan 18, 2010 12:04 am

OK last set of questions in this topic..I promise :wink:

I've made my first spudgun since joining spudfiles. It's a simple over/under sprinkler valve. I want to mod the valve for blowgun. The vids and tuts I've looked at have the bleed valve in the center but the valve I have has it off center. I'm not sure if I should drill out the bleed hole or just make a new one in the center.

OUTSIDE
Image

INSIDE
Image

Fitting I plan to use if center is best

Image

Sorry no gun pics but I'll open a new topic in the "cannons" section soon as I get it painted up and the mods done.Right now there is electrical tape and blocks of wood everywhere...lol

but for now...here is the first test. I know it is nothing special but it was fun.


[youtube]http://www.youtube.com/watch?v=E4t2Crd4ibY[/youtube]
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Unread postAuthor: MrCrowley » Mon Jan 18, 2010 12:17 am

I'd drill a new hole in the centre, remove the bleed valve and epoxy up the hole when you epoxy the solenoid valve hole as well.
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Unread postAuthor: jackssmirkingrevenge » Mon Jan 18, 2010 12:50 am

hahaha! Mom must be so proud :D

Definitely mod the blowgun, you'll be impressed by the difference. Also, 60 psi is a tad low, if you're using pressure rated fittings there should be no safety issues with cranking it up to 150 ;) except your your target of course, the c-cell should go straight through the monitor :D
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