Spuddy Junior Unleashed! (accidentally)

[frozebyte]

Hello all! This is my first piston cannon that works, and it is a coaxial mini! First up, the dimensions of this mini.

Dimensions
Barrel: 7" of 15mm
Chamber: 8" of 22mm
Piston: 0.7" (approx)
Pilot Valve: 1/2" ball valve (has a springy feeling to it when opening, good)
Fill Valve: Shrader

Parts used(all in SGD):
-22mm to 15mm male-male reducer $3.50
-Ball Valve $3
-Steel Pipes $3.80

I designed this while i was racking my brains to make my over-under spuddy to work.


Valve area(big and bulky )




Barrel inside the chamber (i know the barrel is not in the center. Inexperienced :X)


(SORRY FOR THE HUGE PICTURES)
The piston design is special in the sense that it is a regular piston coupled with three pieces of inner tubing that rests on the barrel inside. The inner tubing is used to make the seal as the gasket is too hard.

It was supposed to be a test that shouldn't work, but it did, and it took me by surprise. I happily pumped it up with a regular bicycle pump when i realised it was making a seal, and when i stopped pumping, it triggered about half a second later. The pop was really loud. 5 houses away could probably hear it loud and clear and thank goodness the barrel was facing the wall, firing a blank.

This sounds really great to me, anyone would care to estimate how good it is by sound? The sound really rings in your ear and temporarily impairs it slightly with a blank. I don't think i can fire it here, and more than one shot might alert the cops.

Cheers!
Frozebyte.

I love critics :]
Small is powerful!

EDIT:
-Nobody noticed i have two same pictures here, my bad. Replaced it.
-Epoxy cured, i know the material now.
-Those odd shaped neoprenes work once only(i think, they warped).
-Caliber included

[jonnyboy]

白钢Pipes $3.80 (sorry for Chinese but the shopkeeper gave me this name, supposed to be same as copper but different colour? need confirmation on this)

Ok your talking about your chamber correct? I would guess steel of some sort. I can't see what your barrel is made out of, or the color so if it looks silverish then its probably steel and if its brownish its brass or copper.

Nicely constructed mini. Because of the small chamber size if you double the length with a detachable silencer then it would be pretty close to silent. How to make a silencer

[frozebyte]

Quick reply! Both are the same material, silverish colour. I guessed it would be steel at first, but afraid it was aluminium. Shouldn't steel be more expensive than copper?

Sorry but double the length of the barrel or the chamber? Im guessing its the barrel. Thanks, will need a silencer if im testing it :]

Cheers,
Frozebyte

[inonickname]

Nope, copper is much more expensive than iron. Looking good, lets see sum damage!!!

[maverik94]

looks nice, have you chot anything with it yet? Damage Shots?

[jonnyboy]

Quick reply! Both are the same material, silverish colour. I guessed it would be steel at first, but afraid it was aluminium. Shouldn't steel be more expensive than copper?

Sorry but double the length of the barrel or the chamber? Im guessing its the barrel. Thanks, will need a silencer if im testing it :]

Cheers,
Frozebyte

Aluminum tubing is very light by your pictures it doesn't look like aluminum. What I'm saying about the silencer is one that is the same volume as the chamber and had lots of pockets to slow the air down should theoretically reduce noise 100% but it never does. Essentially the silencer is just a decompression chamber so all of the left over gas slows down to atmospheric pressure.

[frozebyte]

@maverik94
Not atm, its abit loud to be firing in this bustling city of Singapore, and the houses are so compact in a tiny area. Will try to shoot some fat bolts when i have the chance at a teeny grass patch nearby.

@jonnyboy
I see, but i have already epoxied my barrel into the chamber so silencer probably on my next gun. Coaxials are so much easier to build and small ones like these are cheap.

Cheers.

[jonnyboy]

I can't tell from your picture but if you have even 1 cm of barrel showing you can epoxy on threads for a silencer.

[Technician1002]

Sweet mini coax.. Major praise. :wav:

[frozebyte]

@jonnyboy
Sorry for the quality, i wasn't sure how to epoxy an extra inch of barrel sticking out so i was forced to incorporate the barrel into the chamber in the end. Will use a silencer for future designs.

@Technician1002
Thanks alot! Its my first working full metal and piston spudgun so far, hopefully i can modify the ball valve trigger. Can't find any blowgun valves, people don't even know their existence here.

By the way, im using a regular pump that's pretty small, and i don't have a pressure gauge so im not sure how safe it is to fire this thing yet. Will try to get a pressure gauge asap to test out this mini. Go Junior!

Cheers.

[qwerty]

That looks like a realy nice gun but what did you use to connect the schrader to the fitting BTW if you say its to loud why dont you shoot it indoors and also what caliber is the barrel

[maverik94]

ohhhh, that really sucks that you have no good place to fire it. Could you maybe fire it in a basement at your or a friend's house? Then noone would hear it.

[Mr.Sandman]

Im not sure i understand how this works. Do you unscrew the schrader after filling? or is it a 3 way valve?

[frozebyte]

what did you use to connect the schrader to the fitting BTW if you say its to loud why dont you shoot it indoors and also what caliber is the barrel

I left a circular shape of the hard rubber around the shrader, stuffed it into a 15mm male to female in that manner(it gets blocked in the middle of fitting), and epoxied the space on top, i used hot glue before, real good and easy don't you think? The blank was shot in a closed room, still loud as ever. Included it, its 15mm.

ohhhh, that really sucks that you have no good place to fire it. Could you maybe fire it in a basement at your or a friend's house? Then noone would hear it.

Yeah it sucks, Singapore's just too small. There are houses with basements here, but i don't know the owners. Will try to find a way to test it.

Do you unscrew the schrader after filling? or is it a 3 way valve?

I unscrew the shrader, i like it that way cause the shrader is a tight fit even without teflon. Teflon wears easily, not good to keep replacing the shrader. A three-way-valve is like twice the price so i thought it wasnt worth the deal. Might use it next time.


By the way, i have been testing it carefully at lower pressures, and it keeps firing blanks at extremely low pressures(like a puff of air escaping) I unscrewed it and found those neoprene pieces all warped into a conical shape, they probably work once only, will find an alternative.

Cheers.

[inonickname]

To fix your schrader problem just unscrew the core (middle) of the schrader. Open the BV to fill, close it before you remove the pump and no problems.