Hi Paul,
There are several solutions to this problem, but the simplest
(cheapest) one is to talk to suppliers (such as Brandbright in the UK)
who either directly support G3 products, or who support similar
materials for other 'gauges' in roughly the same scale (1:22'ish). If
you need specifc things made, then I would advise you to try and hook-
up with a local model-engineering society (or live-steamers in the
US) and you may well find someone willing to help you out if the job
is simple and relatively quick.
My best advice though, would be to obtain a small lathe and learn to
use it. I believe that you will never regret the investment in time
and money, and that you will find this side of the hobby just as
engrossing - and it makes everything associated with live steam so
much easier (and cheaper).
With regards 'running' a live-steamer, the G3 Society have a leaflet
written by Alan Headech (one of the founding fathers) that covers
this area for this size of locomotive. See www.gauge3.co.uk. There is
nothing to fear from live steam operation provided common sense is
applied, and that you have a properly constructed boiler which has
been correctly tested. Again the G3 society have boiler test
standards that they will supply - they meet/exceed similar standards
operated by the main model-engineering societies over here.
Live Steam in G3 is a great size to work with - enjoy.
Regards, Ian.