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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: Gaderelguitarist » Fri Jun 12, 2009 8:41 pm

Oh Sorry. I guess i got a little confused.

I don't know what you could use for a bolt in 1/2" PVC.

As for the bushings. Theres not really much to explain. All i meant was to do a bolt in the style of Clide's bolt, you could use a piece of 1/2" PVC between two bushings as the chunk of the housing that plugs up the vent holes in the bolt.
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Unread postAuthor: MountainousDew » Fri Jun 12, 2009 9:24 pm

Does anyone know the OD of a 1/2 inch PVC coupler?
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Unread postAuthor: THUNDERLORD » Fri Jun 12, 2009 11:23 pm

pHEw!!! My brains are scrambled...
Must've been the coffee...spent well over an hour in home depot looking at possibilities today.

Looks like if at all possible, copper pipe and fittings would work better for the barrel and bolt.
I came up with a few PVC possibilities.
Problem is they will be hard to explain. :(
And require sanding off some rings and some sanding for fit.

I am thinking the 1" pipe bolt should move inside a 1.25" pipe.
The mag could be constructed from a 1.25" "T".
1" has a gap in 1.25", so some sort of short sleeve would be needed.
The 1.25" pipe does not need to run the full length of the barrel, just a transition from the bolt to the barrel.
The best/simplest possibility I noticed involved :
---a 2" coupling(Body),
---a 2"-1" reducer bushing (1"hole sanded to fit 1" bolt pipe smoothly)This will be the blocker tube, blocking the holes in the bolt sides,
--- a 1.25" coupling and a 1.25"-1" bushing.(these would be cut shorter, fitted on bolt and used to retain the spring)
A 1" pipe and a female/male 1" connector would be glued opposite side of 1"-2" reducer bushing for valve attachment.
Dang, they only had 2" DWV couplings and IIRC, the 1.25" coupling fit inside 2" pipe,(IIRC) so I was thinking of a short piece of 2" pipe for the body, with 2 DWV couplings back to back PVC glued on the 2" pipe for the body.
I might as well give up on sizes here,
i got 4 possibilities, but you'll really need to go and look to visualize everything.

Well, since they only had 2" DWV couplings but pressure rated end caps in 2",
I had one involving using a 1 1/2"-1 1/4" "Trap adapter"(also DWV) the 1" bolt could be sanded down until it slides through the ID.
A 2" end cap would be modified by cutting a hole to accomodate the threaded side of trap adapter, and there is a plastic nut that could be epoxied on the inside of the end cap, to strengthen it (DWV :evil: .
The 1.25" PVC could be PVC glued in for the bolt to move inside ,
1.25" mag."T" and the 1"OD barrel would be sleeved inside, with a taper (for smooth loading), And a hop-up(to keep gumballs from rolling out).
The body would be short 2" pipe, with a modded end cap on each end.

I came up with two more that would be pretty simple, but that would be too long, and they involved combining bushings with rings grinded off, with couplings fitted together to form components.

Dang! this always happens, I get there, design something that will work then have to go back and re-engineer it again when I buy stuff.
(I even took notes which are now pretty incomprehindable) :(
In this case I have no plans to do that, since a more efficient one could be made from copper, and I'm working on a high pressure brass bolt/design similar.

Hope any of this is helpful, I will try to organize the info I got better, or help out/go back if I can.

IDK the OD of 1/2" coupling. will be getting my digital calipers back soon though (very useful spudding tool)...IIRC (from today's adventure) a 1.25 coupling fits in sch 40 2" though... :roll: 8)

BTW, I got the feeling If there were any spudders working there, wondering if I'm one too, now they have no doubts...(and not even my project)....SF's is fun!
I recommend you spend atleast an hour in the PVC or copper section... :P :D

EDIT: If they had a 2" coupling in NSF, more than likely, you could simply use that and a 2"-1" reducer bushing, and a 2"- 1.25" reducer bushing (They didn't have either) Hence, my whacky confusing combination of parts). Your bolt will only travel slightly over .5" and need some space to accomodate the spring.
It's probably a good idea to draw the components to scale on paper or cardboard first....Dang this reply is long... :P 8)
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Unread postAuthor: MountainousDew » Sat Jun 13, 2009 5:42 pm

Okay guys, I have been working as hard as a 13 year old can (Child Labor Laws) and I still can't really figure out a way in which I can make a mini HEAR valve, so I was wondering if I could use something like a QEV+Pop off combo with a Blow Forward Bolt.

Actually, I know it could work but how could I make a trigger?
Because I don't want it to start firing like crazy when I attach the continuous air. The first thing that came to mind, was a blowgun which would work for a bb gun, but not for something with a moderately big bore.

Can someone help me in my time of need?
I said earlier, I can pay you in cookies...
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Unread postAuthor: Moonbogg » Sun Jun 14, 2009 12:12 am

If you want me to I will work with you. PM me the specs of the cannon you want, your existing materials you will be using, your budget and any other details and I will help you design it. I will model it and make you an assembly drawing with assembly details and manufacturer's part numbers.
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