Cummins Drift Truck a la Dum-Dum

[Dave]

For the love of god, please fill this with water.

This is standard practice when doing anything with a gas cylinder (or as paul says n² purging it). You will be suprised how much residual gas is in the bottle even with no tap on sat upside down, it can create a vacuum inside and get held up. Fill it with water after this you'll smell how much it displaces even, and be aware of the blanket of gas sat in your yard afterwards (mine set alight, experienced first hand!!)

The worst worst worst thing you can do is leave it so it is 10% empty and 90% gas, or even 2% gas. Bottle full UEL (upper explosive limit) is 10%, and bottle empty lower explosive limit for propane is 2%.

Its not you i'de be worried about though its the poor bastard who receives your 35kg rocket through their bedroom wall.

It would be pure stupidty to cut into this without properly ensuring gas is gone.