This guide is a short edited extract from MAINSTEAM MODELS "The Complete guide to Miniature Steam" which is now available on CDrom or Internet download. 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.
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.
To successfully run a miniature steam engine, the steam supply must be taken into consideration. BE VERY, VERY CAREFUL when buying secondhand steam boilers from Ebay or anywhere else for that matter. If they are old ones, ie: from vintage pond launches where they were once fired with ferocious paraffin or petrol blowlamps, it is highly probable that they have been seriously overheated in the past. It is recommended that you have the boiler checked out professionally, as you won't know anything about it until the boiler explodes. A current valid boiler certificate is highly desirable with any boiler.
Model boilers are split into many categories & types - here are a few:
Copper boilers - the most common & best to use for general locomotive & marine use
Brass boilers - not recommended for anything other than very small low pressure toy steam boilers
Steel boilers - ok for larger models if certified & tested
Soft soldered simple"Pot" boilers in copper or brass
Old riveted & soft soldered copper boilers - not recommended for any other purpose than nostalgic shelf display
Other types include:
Brazed or silver soldered boilers with soft solder caulking
Silver soldered "Babcock" type boilers with water tubes underneath (like Stuart Turner 500, 501, 504 type, these can be spirit or gas fired)
Brazed or silver soldered horizontal "Yarrow" type multi water tube boilers - very efficient, but usually have small water capacity
Brazed or silver soldered horizontal & vertical single centre fire tube type
Brazed or silver soldered horizontal & vertical cross water tube type
Brazed or silver soldered horizontal & vertical multi fire tube type
Brazed or silver soldered return flue type
Flash steam boilers - very specialist, basically a copper tube that has an absolute inferno blowing at it, water is pumped into the tube by the engine's pump, where it flashes to very high pressure, high temperature steam.
Firing of the above types of boiler (except flash steam) could be meths on the smaller ones, gas or coal on the larger ones. If the boiler is of the type which doesn't hold much volume of water, either a steam, electric or crankshaft driven pump is essential for any duration of running.
Whichever type of model steam boiler that you use - remember - ALWAYS WATCH THE WATER LEVEL. A boiler will be seriously damaged if all the water within it evaporates - the burner will make the flue tube glow red & start to unsolder it quite quickly. Also any outer wood lagging will soon turn to charcoal.
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