Model Engineer and EIM have carried numerous designs for boilers over the years, and the KN Harris book is also excellent. The Martin Evans designed 5" (I think) test boiler is one of the best. Someone else, (was it Tubal Cain) also designed a test boiler. Reeves list, or used to list, one in their catalogue. To make life really easy, there was one design that used a domestic immersion heater as a heat source. As far as I recall, the most complicated parts were for ensuring the water level was sufficient, and the control of the heater. A boiler of this type is not complicated, and is good exercise in brazing etc. without being too daunting. It is worth remembering that apart from the actual boiler, there are, water level gauge, safety valve(s), drain cock(s), and some form of steam regulator, plus, the water supply, either by pump (manual or automatic, or both) or by injector. Well worth making your own, and making as many of the fittings as you can manage too. Alan Stepney http://www.alanstepney.info Model Engineering & steam engine information pages MODEL ENGINEERING DISCUSSION LIST. To UNSUBSCRIBE from this list, send a blank email to, modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.