58
12.7.5 Types of flame
Types of flame change based on the proportion of propane and oxygen.
[Neutral Flame]
Perform brazing with this flame
(This is a flame when oxygen and propane are mixed at proper proportion, and has lesser effect on the brazed
metals)
White core flame
10 ~ 15 mm
Outer flame (Light orange color)
[Carbide Flame]
When propane is excessive, the flame has white color flame in between the white core flame and outer flame.
(This is due to the lack of oxygen and the proportion of unburned propane is excessive.
The black carbon created during the brazing work may contaminate the surface of the brazed metal).
White core flame
Pale white
Outer flame (Blue color)
[Oxidizing Flame]
Oxygen is more compared to the neutral flame. Although the flame size is small, this has the highest flame heat.
However, due to the excessive oxygen contained in the flame, the brazing point gets oxidized. (This flame may cause
holes, due to the high heat. The pipe may get melt
）
White core flame
Outer flame (Blue orange color)
12.7.6 Closing the flame
[In case of short break]
1. Close the “propane valve” of the torch.
2. Close the “oxygen valve” of the torch.
[In case of finishing work]
1. As above, close the flame following the procedure of “In case of short break”
2. Completely close the valves of oxygen and propane cylinders
3. Release the remaining gas inside the hose by opening the “oxygen valve” and “propane valve” of the torch.
4. Confirm the 1
st
and 2
nd
side gauge pressures of “oxygen” and “propane” cylinder pressure adopter are “zero”.
