This guide is an edited extract from MAINSTEAM MODELS "The Complete guide to Miniature Steam" which is now available on CDrom. It is written with the beginner in mind and covers many essential principles for sucessful running of miniature steam engines, locomotives, traction engines & steam boats.
The most common problem with gas fired model boilers is maintaining a consistent gas pressure to feed the burner. Using commercial 70/30 butane/propane canisters has its drawbacks, whether you use them in your model or use them to fill an onboard gas tank.
Even with a small gas regulator fitted, chilling of the gas & subsequent pressure drop will occur.
It is not a good idea to use neat propane on your models, it is at high pressure & can be very dangerous indeed.
Using the commercial mix canisters, I find that it is a good idea to route the engine's steam exhaust pipe under the gas canister, then finally to the chimney. The convected heat from the hot pipe underneath the gas tank will keep the gas tank "aired" & prevent chilling. This is the method that I normally use with great success.
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