A small LPG torch will do what you need in 18ct, even melt 3 or 4
gms of scrap gold or silver into a blob on your soldering pad.
The main items to get are a torch handle with tap, a flexible tube
with screw fittings, and a nozzle (small will do what micro does and
is more versatile) - all available in hardware shops. With these you
can attach a small or large refillable LPG cylinder available in
hardware and camping shops.
A torch mounted directly on a disposable cylinder should do the
same, but last time I looked there is no choice in nozzle size.
I use a LPG torch with a small nozzle for the bulk of my work. I
change to a large nozzle occasionally for large silverware items, and
use an oxy-acetylene torch for melting in a crucible or for welding
and special tasks.