There has been a lot of discussion on torches and gasses which
is best or safest, insurance problems and so on. One option
that may be considered is the Aqua torch which can used indoors
and is considered very safe or lets say non explosive. The
chemicals are slightly toxic on the other hand.
The flame is produced by the decomposition of water forming
Hydrogen which is then dried and mixed with alcohol and flux to
produce a very hot flame which can be used for soldering. Some
models can handle 2 torches and one can be used un-fluxed for
use with Platinum soldering and welding.
The torch does not produce enough heat to cast with but you can
melt about an ounce of metal for milling out. There are several
manufactures that market these torches.
I myself have never had a problem with my Oxy/propane tanks that
I have been using for the last 20 years but in the case of
having a torch set up in a house or apartment this would be a
safe alternative. Jurgen has one and he may be able to give a
more accurate view of the use of this torch.
Edward J. Friedman