Crosman 10oz cylinder

[Jerry Cornelius]

Any thoughts what’s gone on here?





I picked this up at Kempton with a nice 115. I can fill the gun directly from an extinguisher so I don’t need to use the cylinder, but it might be nice. Normally I believe they have a burst disc at the end away from the fill valve. But this one seems to have been modified with what looks like another valve for filling the cylinder

Any idea why anyone would do that? Am I missing something here? The thread in the addition is not 1/8 npt, but it would surely be easier to make an adaptor for the “normal “ valve if the issue was not having 1/8 npt on your master tank.

As for safety, hey ho, yes I’ll be careful and weigh it before and after a fill.

[Leonardj]

Appears that someone has modified the burst disc nut to use it as a filling system.
Would be a good idea to remove the assembly and give it a good inspection. If it has been adapted to use as a fill port, you will no longer have the protection of a burst disc.
As well, it appears that the adapter has been soldered to the nut. If this is just "soft" solder, it could pose a potential safety hazard, unless there is a mechanical connection in addition to the solder.

[Jerry Cornelius]

Yeah, I didn’t like the look of that solder either, although if I don’t use that valve for filling I don’t think it will ever be subject to pressure. But I’m going to take the fitting off to investigate

As for no burst disc, I can manage that by always underfilling.

[eyebull]

Yeah, I didn’t like the look of that solder either, although if I don’t use that valve for filling I don’t think it will ever be subject to pressure. But I’m going to take the fitting off to investigate

As for no burst disc, I can manage that by always underfilling.

Doesn't CO2 act a bit differently to compressed air, in that it's always at the same pressure if in liquid form?

[Jerry Cornelius]

Doesn't CO2 act a bit differently to compressed air, in that it's always at the same pressure if in liquid form?

Indeed. At a constant temperature the liquid and gas are in equilibrium at a constant pressure. The danger comes if you overfill a cylinder and then the temperature increases. If there is not the space for liquid to evaporate to gas, pressure can rise drastically. Also the increase in pressure of CO2 with temperature is much greater than with HPA

In that sense CO2 is potentially more dangerous than HPA, despite the lower pressures overall

Or that’s my understanding