Actually the pressure in a gasoline tank is exactly the same whether the can is almost full or almost empty or half full, in exactly the same way as the pressure inside a propane tank stays constant right up until the last drop has evaporated. Pressure varies only with temperature.

Worst thing you can do is to leave the lid a little loose because you get a constant flow of vapour out of the top - where it can be ignited - until the can is completely empty.

The wisdom of buying cheap gas cans is for you to decide, but if it is truly meeting the specs, it is designed to hold the pressure up to a certain content temperature without leaking. If you can't stand the sight of a bulging can then either don't ever look at it in the hot part of the day, of else put it in the shade with a wet cloth over it.

My clear preference is to buy a quality plastic gas container - Rheem or similar - because it is totally immune to the flexing and crinkling that results in minute pinholes and cracks that make metal cans so dangerous. However, on a stinking hot day they end up looking like footballs, but the factor of safety is more than adequate. But yes, coke bottles are pretty strong but the opening is surely too small to take a standard fuel nozzle? and it is usually illegal to fill them.

As for static - not as likely as you think provided you are not doing the quickstep wearing nylon underwear while undoing the can - and even then .... A metal can will cause any charge to collect on the outside and just placing it on the ground will immediately dissipate all charge. Decent plastic cans will also have compounds to leak away any static.

What is a big no no is to fill a can or the vehicle fuel taank when it is insulated from the ground by being in a vehicle, or you holding the bike upright in insulating shoes, opening the tank and then your mate bring the earthed fuel nozzle to the tank opening. TCan should be sitting on the ground, or bike on the stand and even then touch the fuel nozzle away from the opening before filling and hold the nozzle against the side of the filler neck while fuel is flowing. Can't get a spark across a short circuit.

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Tony
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