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spud guns I've made

Posted: Wed Apr 16, 2008 10:27 am
by Stephen Holliday
These are spud guns I've made. Nothing elaborate, but all shoot great.
The first on is a breech loading rifle with a 1 in. barrel about 40 in. long with a 2 in. air chamber. The ball valve open back so I can hold on target.
The second one is basic spud gun with a 1 1/2 in. barrel that is 4 ft. long. with a 2 in. air chamber.
The 3rd on is a piston valve made from a soup can with a toilet flapper as a seal and a rubber bumper on the end of the can. The barrel is 1 1/2 in. with a 3 in. air chamber. The exhaust valve and fill valve are built in the screw on cap.
The last one is the first gun I ever built. It has a 2 in. barrel and a 2 in. air chamber. The valve is a 3/4 in gas valve. The gas valve inner threads were notched out on 2 sides and the stem threads were filed down on 2 sides. A spring is between the valve and the handle. When you pull back the lever handle the stem lines up with the notches in the valve and moves stem out for a quick release of air.
Push the handle in and forward for the next shot.

Posted: Wed Apr 16, 2008 11:14 am
by sniper hero
nothing special but a nice collection
but on the 1st is the last part of the stock that goes I think on your shoulder (most left) part of were the air goes through?
because if so the flow is reduced

and I love the paint jobs from the lower 3

Posted: Wed Apr 16, 2008 11:44 am
by Stephen Holliday
The air goes through the tees nearest the valve. The stock part is plugged.

Posted: Wed Apr 16, 2008 12:06 pm
by biggsauce
Nice lookin stuff ya got there! :wink:

Where did you find the vavle on the bottom cannon? I like how it works...

Posted: Wed Apr 16, 2008 12:59 pm
by Stephen Holliday
It's a 3/4 gas valve that has a brass stem and seat, not rubber like a water valve. It screwed down like a regular water valve. The end of the valve stem is tapered and the seat is countersunk so it doesn't leak. You shoud find them at any home improvement place. the handle is from a electric switch that you turn on & off.

Posted: Thu Apr 17, 2008 1:18 am
by XxtriviumxX
Thats a nice collection you have there, I like the camo paint jobs. :D

Posted: Thu Apr 17, 2008 7:32 pm
by e1337
Nice I also love the paint jobs but you have DWV fittings on your third one, the bell reducer and the clean out cap are not pressure rated.


-e1337

Posted: Thu Apr 17, 2008 7:37 pm
by STHORNE
nice job.... i love the paint jobs...

Posted: Thu Apr 17, 2008 8:18 pm
by Stephen Holliday
I don't go over 100 psi in any of them. I thought all schedule 40 fitting were the same.

Posted: Thu Apr 17, 2008 8:51 pm
by DYI
As you probably know, SCH 40 is a thickness rating, not a pressure rating. The problem here is that DWV PVC fittings don't have incredibly high quality control, as they are only meant to be used at the maximum pressure that might develop in a drain system - likely no more than 10 psig or so. They seem to have shorter sockets and all around less satisfactory construction than PW PVC fittings.

This knowledge is only from observation of other people's catastrophes. I've never used PVC myself, as I'd like to keep all of my body's systems functioning as long as possible, and PVC shrapnel doesn't help that cause.