The Essential Beginners Guide to Live Steam Models:
This guide is a short edited extract from
"The Complete guide to Miniature Steam" which is now available on CDrom or Internet download.
Filling Gas Tanks Used In Model Steam Boats
Many people seem to have difficulty in filling their gas tanks in model steam boats successfully. Assuming that you have the correct adaptor, fitted to a Butane/Propane mix blowlamp canister, it is a simple job, but getting sufficient liquid gas into the gas tank can be tricky.
Here's how to do it:
Never fill the gas tank whilst it is still in the boat.
The gas is heavier than air & will accumulate in the bottom of the boat.
This is not good when you come to light the burner!
It is very important that the gas tank used in the boat is at a lower temperature than the Butane/Propane canister, so make sure that the boat's gas tank is not being held in your hand, which will warm it up.
If it is not possible to fill the tank with the tank on the bench, then hold it with a cloth to insulate it from your body heat. You do not need to insulate the Butane/Propane canister from the warmth of your hand, in fact it is the temperature differential that causes the liquid to flow from the canister into the tank. After a run, the tank will be cool anyway owing to evaporation of the liquid gas, but before the first run of the day, the tank will probably be warm if it has been in your car, workshop or out in the heat of the sun.
If the tank is warm, it can be chilled with some of the liquid gas by letting some liquid gas escape onto the surface of the gas tank.
Needless to say, filling of the gas tank must be done outside, and also well away from naked flames!
Definitely No Smoking!
Occasionally lift the filler valve to let the tank valve ventilate. Shaking the gas tank & listening to the liquid gas sloshing about inside is a good indicator of how much liquid gas is in there, also the weight of a full tank is a good indicator too. The Butane'Propane canister of course will become lighter in weight as the gas travels down into the gas tank.
Caution:
You must not fill the gas tank right up to the top, that is a bad idea, because liquid gas could spill into the burner feed pipe with dire results! So to sum up, keep the tank to be filled cool & the filler canister warm & you will have no problems. However, a little patience is required, as it takes a few minutes to fill a large gas tank.