more rather distinctly defined flames. The inner one at the torch tip is
very small, and the intermediate one is long and pointed. The oxygen should
be turned on until the two inner flames unite into one blue-white cone from
one-fourth to one-half inch long and one-eighth to one-fourth inch in
diameter. If this single, clearly defined cone does not appear when the
oxygen torch cock has been fully opened, turn off some of the acetylene
until it does appear.

If too much oxygen is added to the flame, there will still be the central
blue-white cone, but it will be smaller and more or less ragged around the
edges (Figure 39). When there is just enough oxygen to make the single
cone, and when, by turning on more acetylene or by turning off oxygen, two
cones are caused to appear, the flame is neutral (Figure 40), and the small
blue-white cone is called the welding flame.

[Illustration: Figure 39.--Oxidizing Flame--Too Much Oxygen]

[Illustration: Figure 40.--Neutral Flame]

[Illustration: Figure 41.--Reducing Flame--Showing an Excess of Acetylene]

While welding, test the correctness of the flame adjustment occasionally by
turning on more acetylene or by turning off some oxygen until two flames or
cones appear. Then regulate as before to secure the single distinct cone.
Too much oxygen is not usually so harmful as too much acetylene, except
with aluminum. (See Figure 41.) An excessive amount of sparks coming from
the weld denotes that there is too much oxygen in the flame. Should the
opening in the tip become partly clogged, it will be difficult to secure a
neutral flame and the tip should be cleaned with a brass or copper
wire--never with iron or steel tools or wire of any kind. While the torch