SpudFiles

At last ive finished my 22mm coax It took awhile waiting for all the parts but i finally made it. I need to fiddle with the piston a bit because it's still not perfect but getting close.
Secifications:
Piston: hot glue, rubber washer, and a bike innertube on top
Chamber: About 40cm of 22mm copper pipe
Barrel: 70cm of 10mm alluminuim tubing
fill valve: Good old schrader
Pilot: blowgun (but im thinking of putting a pushbutton valve on it)
Thats it Theres a sneek peek of my 22mm tee piston but its not finished yet. Damage pictures will come soon. BTW do you think i could do with a bigger pilot?


The gun itself without the stock (and some toes)


Thats not the actual piston but it looks a bit like it.


With the stock on.


And theres the half done 22mm tee piston

Constructive critisism welcome

Do you think you got enough recoil pad on there lol ! I like the way you mounted this in the stock. Turned out nice. Shooting pics and vids in the making?

it looks pretty good... I hope you've got some source of high pressure

BTW
nice feet...

now that I think of it it's good that you put feet in your pics.... it could have been worse

That looks so good on the stock that I'll ignore the toes well worth perfecting the piston in my book, though it does need a heavier barrel aesthetically... you could add a barrel shroud what would act as an integral suppressor too, and agreed with POLAND_SPUD, this wants at least 300 psi

Well i can pump this up with the shocky but my piston is still opening slow

qwerty wrote:BTW do you think i could do with a bigger pilot?

A blowgun should be more than adequate, is your piston too tight/too loose?

it could use a better pilot valve... but push button valves are not ideal

small direct acting spool/poppet valves (5M - 1/8") might offer too little flow for 1/2" QEV if not opened fast enough... but this is true of other valves as well...


of course the best idea would be to use a push button valve and a small QEV to help piloting

is your piston too tight/too loose?

It dosent feel to loose or tight i think when i cast the piston the bit of pipe was slightly squeezed so im casting another at the moment.

but push button valves are not ideal

but people say homemade pushbutton valves open faster than blowgun and have a higher flow.

At last ive finished my 22mm coax It took awhile waiting for all the parts but i finally made it. I need to fiddle with the piston a bit because it's still not perfect but getting close.
Secifications:
Piston: hot glue, rubber washer, and a bike innertube on top
Chamber: About 40cm of 22mm copper pipe
Barrel: 70cm of 10mm alluminuim tubing
fill valve: Good old schrader
Pilot: blowgun (but im thinking of putting a pushbutton valve on it)
Thats it Theres a sneek peek of my 22mm tee piston but its not finished yet. Damage pictures will come soon. BTW do you think i could do with a bigger pilot?

Constructive critisism welcome

Somebody likes smilies 8) ! ! lol
Very nice looking gun. Did you make that stock yourself? It looks almost storebought, but I could be wrong. Very nice, I look forward to seeing damage pics!

The stock is a logun PCP airgun stock that i got for £16 from an auction
And unfortunatly there wont be any damage pics until i can get a good, effective piston.

Do you think i could o ring a hot glue piston with a poor mans lathe? i might try this to improve performance because at the moment it has the power of a spring loaded BV (I dont normally use so many smilleys )

You can make a o-ring groove in a hot glue piston with a soldering iron, home made lathe, drill press, just about any way you want. attack of the smilys

Looking very nice. Like JSR said, a blowgun will do, but if you're reaching for that little bit extra, perhaps even 50fps or more, a 1/4" ball valve or a well design push-button valve will work great.

Like on my co-axial, the difference between a blowgun and a push-button was being able to shoot through a piece of wood with the push-button, but only being able to get the metal BB stuck in the wood with the blowgun.

edit: Of course this heavily depends on your piston, if you build pistons like JSR does, you could pilot it through a pin hole.

Spring loaded 1/4" BV as a pilot? Combined with an optimum piston I cant see what would be wrong with that. I'm looking forward to some damage pics; what are you planning to use as ammunition?

Absolutely love the stock too . I would suggest a scope but even iron sights would make this aesthetically brilliant.

Thanks guys, i might order a cheap scope of ebay and i allready have ordered 200 9.5mm ball bearings for ammo but my piston still opens very slowly so don't expext them anytime soon. BTW can hobby WOOD lathes cut nylon plastic?

In case others are interested, reposting the reply to your PM here:

Have a look at my tutorial

As long as your piston is reasonably light, tight fitting yet friction free, you can get away with a small pilot valve. Have a look at this project, a 1" piston piloted by a simple schrader valve. Your blowgun trigger is enough, you just need to optimise your piston setup.