Acetylene
Hydrogen
LPG
Methane
L mm
L + 2 mm
L + 4 mm
L + 6 mm
oxidizing flame
neutral flame
carburizing flame
slightly carburizing flame
almost touch the work
be 10 mm away from the work
be 2 mm away from the work
be 5 mm away from the work
be more
of correct size
be less
not be affected