NITROUS OXIDE ( nos / n2o ) advice forum

Allright guys,
Just a quick question regarding a big bottle of medical nitrous i finally managed to bag to fill my smaller WON bottle.
When plumbed into my car's system the mechanical pressure gauge fitted into the dash only went up to a scarce 600psi with the bottle connected directly, the bottle was brand new and sealed. Anyone know what pressure a filling tank must be in order to transfer 1 bottle's nitrous to the slave bottle?
No chance of heating the main bottle 'cos the bugger's too big! I'm thinking that the pressure is way too low...but why?

Pressure is entirely dependent on temperature, so when a bottle is cold the pressure will be lower than when it's hot.

You NEED a pressure DIFFERENTIAL between the 2 bottles and there is only 2 ways to achieve that;

1) Get the temperature of main bottle higher than the bottle being filled - this can be achieved by cooling the small bottle (in a freezer) or heating the large bottle and if you don't have access to a heater, you'll have to wait until the sun shines and put the bottle out for some sun bathing when it does.
2) Get the height of the main bottle much higher than the bottle being filled.

Thanks Trevor, I think it's the only way as filling the won bottle here in Rome is impossible so i'll have to do it all my self.
Certainly no problem regarding the bottle heatin, It's gonna be pushing 40 degrees here soon..!

You need to keep the vehicle bottle cool and the best way to do that (apart from the obvious), is to vent off the dregs of the gas/vapour in the vehicle bottle JUST BEFORE you're ready to fill it, as that cools the bottle.