NITROUS OXIDE ( nos / n2o ) advice forum

Put the big supply bottle in a warm place to heat it up to at least normal room temp or higher for a few hours.

Put the bottle to be filled somewhere cold for approx 1hr.

When the bottle to be filled is cold and supply bottle is warm continue as follows;

If the supply bottle has a dip tube fitted (usually indicated by a white line down the length of the bottle) it should be stood upright with the valve upper most.

If the supply bottle does NOT have a dip tube, it should be turned upside down (with the valve at the bottom) and raised approx. a foot or so off the ground.

If the bottle to be filled has some content or you have not cooled the bottle adequately, position it so the valve is pointing at the ground and purge off some of the nitrous "GAS" then close valve - this step is not required if the bottle is completely empty.

Lay the bottle to be filled flat on the floor, preferably on scales to measure the weight.

Now connect the supply bottle to the bottle to be filled using the nylon pipe supplied. Open the large bottle valve and CAREFULLY slacken off the pipe securing nut where it connects to the small bottle. To avoid any risk of freeze burns wear a protective glove for this job. When you see WHITE vapour escaping from the pipe joint, nip up the securing nut until it is sealed then finally open the small bottle valve.

Due to the contents of the supply bottle being above the bottle to be filled and the differential in pressure, nitrous liquid will fill the small bottle.

If the bottle does not reach the full weight after approx. 15 mins lift the bottle being filled a couple of inches off the floor and gently rock it from end to end, then place it back down for a further 5 to 10 mins or until it is filled.

When finished close both valves and then carefully release the pipe retaining nut at the bottle being filled (avoid the escaping nitrous) and then check the weight. If the total weight is higher than the gross weight stamped in the neck of the bottle, any surplus should be vented off.

NEVER LEAVE A BOTTLE THAT'S OVER FILLED FOR ANY TIME, as the pressure will eventually and suddenly rise excessively, causing the SPRV to vent off gas.

For best results warm the bottle back up to at least ambient temperature before fitting and using.

The Warm place, can be at garden with sun?
The Cold place can be in a freezer or cold storage room?

The best way to cool the car bottle is in a freezer and lots of people do this way
if you live in a climate which can heat a bottle in sunlight its a great free method to heat the big bottle

I've found the big bottle takes plenty of heat input to warm it above stone cold in the British summer

Portuguese sun should be fine but can you send me a pic of the bottle valve to make sure it doesn't have a blow disc in it, because if it gets too hot with a disc it would rupture.

Ideally you should have a pressure gauge connected and get the pressure up to approx. 1,000 psi

As Moo stated, nitrous wont congeal and I think you've probably got the wrong word there but if you cool it for too long, it could lead to the bottle getting over filled and that IS TO BE AVOIDED.
Ideally you fill the bottle whilst it's sat on scales and ONLY fill it to the weight shown as GROSS on the neck of the bottle.

So big bottle in sun is ok...
And 11lbs bottle is freeze 1 hour! (Freeze is maybe between -10º and -5ºC) in 1 hour bottle not congeal and I can't do transfer? I not understand very well your explanation, because some explanation you use I not understand it very well (I'm not English)...

Trevor, I not have the big bottle yet (it's very dificult buy it here in Portugal ), if I not can buy 1, i will send my 11lbs car bottle to fill in a Car Office (it's too expensive, but maybe not have another solution)