When starting the boiler of the Jukliet loco I tried various sources of heat withour success. Two proffesional boiler makers told me they use acetylene.
This is very expensive for the occasional user but then I found a source which supplied me with Map/Pro gas and a large (about 2 foot tall) oxy bottle. The kit comes with everything including a trolley but you need to buy a No 28 nozzle as well as the ones supplied are too small
Now no problems silver soldering the boiler.
Tel: +44 (0)1291 431373
They are based at Caldicot, Gwent a stones throw from the Severn Bridge.