SpudFiles

poor smileys

right now I am pretty much anoyed... I've spent a couple of hours trying to build a T with no success...
I think It might be a good idea to build a custom T using epoxy...
probably I could build it completely from metal pipe fittings - but I don't have the right parts now and I could reduce dead volume so I am ready to try new things

anyway this is what I want to built... the only question is whether it will be strong enough to handle 500 - 700 psi ??

how thick would it have to be to be safe??

ps sorry for low quality of the pic.... uhmm I've been using cheap batteries, you know...

potatoflinger wrote:Why didn't you epoxy the aluminum plate to the box?

Check out the difference in tape between the first and second videos It's down to the heavier, slower projectiles deforming the plate as opposed to punching straight through like my smaller calibre efforts.

Pressure buildup? Hmm. You could always try, right?
Well anyway I think you'll have to use a tubemag.

While testing at first I hadn't put thread tape on one of the connectors and it was leaking ever so slightly, the thing never fired because it has to reach a minimum pressure in the chamber before the BB can be pushed out. Even with the detent fully loosened there's still two fairly tight BBs to contend with.

anyway this is what I want to built... the only question is whether it will be strong enough to handle 500 - 700 psi ??

how thick would it have to be to be safe??

First of all it would need to be proper epoxy as per PM, 5-10 millimetres thickness should suffice. You should however add reinforcement to be extra safe, one thing I like to do is wrap the piping in wire first, or add stiff longitudinal members (decapitated nails for example) along the pipe. I've used this stuff up to 850 psi in my HPA Rattlesnake, nothing blew up yet

ps sorry for low quality of the pic.... uhmm I've been using cheap batteries, you know...

MrC, whereforth art thou?

MrC, whereforth art thou?

I saw that before, decided not to comment
Though I did buy some better batteries, expect some medium quality damage pics!

MrCrowley wrote:expect some medium quality damage pics!

lolol excellent

because JSR posted his update I feel obliged to do the same
even if I don't have anything worth showing and my cheap batteries are almost dead


I planned to use epoxy but I couldn't find it in my town so I bought a 3/8" T that I needed to build the loading mech completely out of fittings (I am sure I had one somewhere in my basement anyway but I couldn't find it... my father must have borrowed it or something)


the design of loading mech is basically the same as the one used on the previous (16mm cal.) version of this gun...

this time I decided not to cut ports in the barrel but to use a small plastic T (exactly the same as the one presented in my previous post...) and hot glue it inside a 1/2" iron T... thx to this the barrel is now removable

but don't worry hot clue and the plastic T don't handle pressure... the idea is that the iron T is sealed upon firing by the bolt attached to the air cylinder so there is no pressure differential acting there...

those parts are there only to guide the ammo (the plastic T), to reduce dead space and keep everything in place (hot glue)


becasue it's late now I could only fire 10 or so shots at 100 psi to test the loading mech.. so far it looks promising


ohh.. until my shipment of fittings arrives I use the gun as a high pressure single shot gun with interchangeable barrels...
that's why there is a BV as the pilot valve and the 5 way spool valve to test the loading mech....

on the final version there will be a 3 way manually operated spool valve to operate teh air cylinder and pilot the QEV

ohh threads on 88g cartridges are very close to 3/8"... size isn't a problem but different twist rate of the threads is... you can only screw it in full 3 turns, which makes it pretty tough to both seal the cartridge perfectly and pierce it... so I might need to buy a proper NPT-to-metric threads adapter

Looking good, but as always videos would be appreciated

I just bought a couple of 1/8" fittings and attached the manual valve... I was afraid that the valve might be too small to pilot the QEV but it works fine... so far I tested it to 200 psi only and I fired a couple of single shots (muzzle velocity seems to be pretty impressive - no video yet - sorry)

now I just have to build a spring loaded mag and use the other side of the air cylinder as an air spring (I can't use a normal spring as that would shorten the stroke)

so far it looks good but normally problems start when you have to transfer from single shots to reliable feeding...

POLAND_SPUD wrote:so far it looks good but normally problems start when you have to transfer from single shots to reliable feeding...

Don't I know it

Still racking my brains over a reliable feed mechanism for a high pressure 4.5mm launcher. I'm considering combining a form of blow-forward bolt with the detent system to make a powerful portable semi-auto.

The forced blowback seemed promising..

The blocker bolt I made would also be able to handle it, as long as the mag is spring fed.
Just a little complicated to make..
Maybe it should be combined with a T bolt and the forced blowback...

IF you get it right it will work very well for this purpose..

Can't wait to see this new version in action...