SpudFiles

I was thinking that maybe if you were to take a compressor and pump up a reservoir to the highest pressure that the compressor could go to. Then that reservoir contained another air compressor that in turned filled a relatively small pneumatic gun. Do you think that this is possible, there could probably be some major flaw that I’m not thinking of. I think that this could work if the gun was also filled to the same pressure as the reservoir, then when the second compressor was turned on there would not be a new atmospheric pressure around the compressor, so it would pressurize the chamber to much higher pressure because it is pumping in more air than usual. I’m thinking that this process could be repeated to reach very high pressures with a regular air compressor.

I do know that it would not be the fastest and best way to do it but if you just feel the need to shoot something with a very powerful punch it could work.

I’m asking this because I am working on my design for my hybrid that includes an outer chamber filled with compressed gas, and I need very high pressures, high enough at which no air compressor could provide ( at a reasonable price).

If you think this could work please tell me, if it will not work please tell me why, I will say that I may not be seeing any obvious flaws that it might have so be nice!

You might run into issues relating to the compression ratio of those pumps; that is, your pressure chamber in which the second compressor is located is at 10 atmospheres, so that compressor would reach maybe 90 atmospheres (gauge) at the bottom of it's cycle.

That would require more torque than your compressor can deliver, so it'll stall.

How about taking a segment of metal pipe, installing a 300 psi (or so) pop-off valve, and filling it with dry ice? Such a device wouldn't be very expensive and would reliably - and wirelessly - deliver high pressures.

What if you were to get a pretty acurate digital scale and then weigh a certain amount of dry ice out then put it into the cannon, Id have to do some calculation for the size of the chamber and how much psi I want, but it would be possible would it not to control the maximum pressure that is attained.

It would mess up PVC and you'd kill yourself if you tryed to shoot the gun...

COLD TEMPERATURE + PVC = BRITTLE PVC

ya, just use a metal pipe and run a hose to ur cannon

You don't need a fancy, highly accurate scale; pressurizing a 1L chamber to ~260 psi (22.4 atm) requires 44g of dry ice, so errors as big as several grams don't make much difference.

If you chose to pursue that route - using water as a temperature moderator, of course, I suggest trying a scale like <a href="http://images.google.com/imgres?imgurl= ... G">this</a>.
They go for really low prices, and a similar model has served me well in my pyrotecnic endevors.
You'll want to debur the indicating needle, though. As provided, it has some stamping artifacts which cause it to be pretty much useless as a measuring device. Once you do this, you should be able to get at least +- 2 gram accuracy.