SpudFiles

I have been working on this bad boy for about 2 months now. This is my first co-axial as the names suggests. I definatly reccomend building one of these as your first piston because it was so easy .

The Specs:
Chamber: 420mm of 50mm PVC (Grade F in NZ it is 3mm thick)
Barrel: 490mm of 25mm PVC (Grade E in NZ it is 2.5mm thick)
Valve: Piston Valve made of a deoderant can lid and has a inner tube sealing face (soon to be replaced with neoprene)
Pilot: 1/2 inch ball valve
Fill: Car tubeless tyre valve from Repco
Special Features:

• *Openable piston houseing
  *Light weight
  *Easy to reproduce

Pictures a soon to come this afternoon.
Hope you like the sounds of this one!

EDIT:- Here are the newest photos. I have been working on thi s for a VERY long time (funding is a problem for a person with no job in NZ)



Rest of the pictures uploaded here http://s72.photobucket.com/albums/i177/ ... Bazookair/

Yes I know that the Pilot and Fill Setup is not perpendictular... I dont know how but it got threaded wrong.

Sounds killer! Some pictures would be nice though....

'Bout time another Kiwi jumped in on the Piston Valve concept

Sounds great, hurry up with the pics

I have had a bit of a problem with everything (leaks) so the pics may be a little while. I'll try to get them today finished or not.

What do you think of the name?

microman171 wrote:What do you think of the name?

Pretty original

No the best pic ill admit but the camera card was full. Better pics ASAP. Im still trying to fix leaks and such.

Without futher ado:


The gun without the end cap

The pilot valve with the rest of the gun

The piston it self with the neoprene sealing face

Have you got this gun working before?

What's supporting the sealing face?

You should probably reinforce the piston too, having it empty adds to the pilot volume.

Also that reducer doesn't look pressure rated. Correct me if i'm wrong, but i've never seen one of those pressure rated though they kind of do look it.

Can you tell me what markings are on the fitting?

It is definatly pressure rated. the plastic is 6mm thick in the tinnest place The other reducer (you cant see it but it is inside the big one looks like a bushing and it is 8mm thick. On the big one it says: IPLEX pipelines 823.50.40 P0085040 50x40mm uPVC AS/NZS1477 PN18, and the other one says: IPLEX pipelines 824.40.25 P0054025 40x25mm PVC AS/NZS1477 PN18

I got these from a plumber who got them in from somewhere. I asked for pressure and they definatly look the part. The plumber knew it was for a pnuematic spud gun.

Yes I used to have this fireing all the time. What do you mean? The deoderant lid (BRUT brand) is the piston all on it's own and the sealing face is made of pencil case (I think it is neoprene). That may be why it isnt working currently, the piston used to occupy less space but I increased this siz incase something happened. I will try filling the piston when I get some more hot glue. Dont know why but some of the fittings are starting to leak It may be because they were glued with super glue then I took them off and re-glued.

Here are the latest pics. Still no glue so I dont have a video yet.



























Hope you like them!

Sorry about the blury pics, I didnt have a flash diffuser so I couldnt take macro phtos inside.

Okay they appear to be pressure rated. Did you use primer when gluing the fittings on?

Ha, it appears your piston is backwards...the sealing face goes on the otherside. And a plastic cap will need to be reinforced.

No I cant really afford it. I know that it isnt a good thing not to use the PVC glue but at like 15 - 20 for a small amount of glue, super glue is so much cheaper and as I have seen the fitting breaks before the glue does (I have had PRESSURE fittings and PRESSURE pipe snap when trying to remove the parts before the joint fails. This is ver re asuring to me. Is the piston backwards a bad thing? I have it working now . The hot glue makes an excellent seal with the PVC with the super glue holding the part on. I only go up to around 100 PSI even though I know the fittings and piep are rated for a minimum of 213 PSI. Finding neoprene is so hard for some reason, what are the washers called? When I went into my mitre 10's plumbing section the staff had no idea what it was (the lady I spoke to has been working there for a very long time and is a gold mine of plumbing information)

Please do not use this cannon if you haven't used primer and/or you have used superglue.

I know it seems it will explode etc but the pipe it self breaks before the glue does.

Seriously, do not use the gun without the proper primer/pvc glue combination. Chances are, it might work for a while and then unexpectedly fail, injuring you or others. Super glue may seem strong, but it is not worth the risk. My guess is that the fittings/pipe broke is that you were twisting, squeezing and otherwise maltreating the pipe and fittings. There are many stories on this site where people have used the proper construction methods/materials and have been injured or at least scared very badly.

I know the feeling of having wanting something that shoots, and wanting to skip some building steps to get there, but do it the right way and it is much more satisfying. I know I may sound like a party pooper (great term) but air pressure is scary. You have the right idea, just do it again the right way.

microman171 wrote:I know it seems it will explode etc but the pipe it self breaks before the glue does.

Ah I seriously doubt that.

I know it seems like everything is expensive, but that's the way it is. I've spent over $2000 on this hobby in less then two years. If it's too expensive for you, move to America or get out. DON'T CUT CORNERS!

Mate, I've had 270psi, that's right PN18(same as your fittings) pipe and fittings blow up on me at 110psi and that's when I used the proper glue and primer solvent welding techniques.

You're not even using the right glue. Which even if you were doesn't bond correctly without primer.

Sorry but i'm not going to help you with this cannon anymore, i'm just helping you making it work better, which will be far more deadly if the sh|t hits the fan. Not worth the risk.