sodastream cylinders are, IIRC, TP 3600psi.

I suspect he's talking about using a modified ballvalve, presumably with an external pivot, as the break barrel mechanism.

Rather than doing that, I'd personally drill into the ballvalve at 90° and use the ball itself as the loading port.

You might want to take a closer look at your trigger mechanism. The trigger / sear doesn't appear to be holding the hammer in any way. The least painful way to put images up (without having to bother with resizing etc) is to use a host like tinypic.com, and put the image url inside [img] tags. Hell,...

The 250 bars is maximum *input* pressure, as a welding regulator it's not expected to put out more than 5 or 6 bars; I'd be surprised if it can put out the sort of pressure you want for an air gun.

Also, negatives, although on less than 1% of transactions...

As you build up pressure on the output side, you eventually get to the point where your compressor can't compress the air on its output side any more. It will keep trying, but it won't generate any more pressure - you can't go higher than its maximum pressure*. The compressor itself won't stop when ...

Looking at the patents might be of use; it certainly seems that the idea should work.

For example, http://www.google.com/patents/US4685236 "Graphite/metal matrix gun barrel", and the various referenced patents.

I've not found anything with a *single* layer of helically wound reinforcement, though.

Planning to run all the filaments around the circumference? How are you handling longitudinal stress in the barrel? Will be a pressure (stress) wave moving the length of the barrel along with the projectile. I'd suggest a layer of unidirectional carbon fibre tow (or similar) running longitudinally,...

I wonder if you would get an air spring effect reducing the valves power when the vent reseals as the piston begins to move back? (between 2nd and 3rd diagrams) I think the answer to that is "yes", but I'm not sure how bad (or, indeed, good) it will be - it's gonna depend on how much air gets vente...

So, been toying with this idea for a while. Elements of the balanced spool quick-dump valve with a QEV-style piston, incorporating a trigger mechanism. Should autocock (and, if you hold the sear away, go full-auto ratatatatatatatata). Here it is cocked and ready to go. The spring exerts pressure on ...

Not sure where wood glue fits into that, all i know is that one takes a while because it requires interaction with the molecules that make it hard, i did say i was using wood glue right? Yeah, wood glue is kinda implied given that you were talking about gluing wood together. If you reread what I wr...

Just remember the more area being held together the longer the glue takes to dry because there is more glue to oxidize, making it dry from outside to inside. after a few days to 2 weeks depending on the glue and surface area being glued. *Ahem* bullhockey. The amount of time you need to leave is ve...